Solar Energy Attic Air Heat Reservoir System
A solar energy attic air heat reservoir system including methods for selecting, installing and operating air movers coupled with HVAC components, air filters, and thermostatic control devices operating systematically for space heating. Solar insolation conducted through building roof materials heats the large volume of attic airspace sealed from normal ventilation during heating season to preserve heat energy, with heat transfer coefficient of convection contributing to and sustaining heating of attic air. Thermostatic digital temperature control devices communicate in series between the building attic and interior for optimum used of heated air supply for environmental control. Methods include computer program applications for feasibility, apparatus selection, operation, and energy cost accountability to enable optimizing space heating using the limited daily solar induced heat. Methods include advantageous containment of thermal energy stored in building interior materials as gathered from attic-heated air for later release through diurnal temperature variation to augment space heating.
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FIELD OF THE INVENTIONThe present disclosure generally relates to a building structure heating system in particular to methods and apparatus employing heating and air conditioning (HVAC) components to transport heated attic air derived from solar insolation conducting through roofing materials into attic air space, with such attic-heated air used for space heating. Heat energy, generally described as Btu (British Thermal Units) hereinafter expressed as Btu/h (Btu per hour) and Btu (Btu is both singular and plural), is the primary heat measurement method used in the United States HVAC industry. Traditional HVAC systems generally produce sufficient Btu measure for economical and efficient space heating by design. However, continued improvements of HVAC systems are being encouraged through government mandate to promote energy efficiency. Common heating fuels used in traditional space heating systems are natural gas, propane, coal, electricity, steam, and wood, each of which have known Btu measure output. Natural heat produced by the sun, with its Btu also measurable, is suitable as a fuel source for space heating. The technology for methods and apparatus of the present invention disclosure employs heated air in an attic that is of sufficient temperature for space heating with such heated air supplied through HVAC ducts to the building interior. Prior art uses of solar energy as a fuel for space heating has been developed over many years within a variety of apparatus and methods that include passive use of solar energy incorporated in building architectural features, and active use of solar energy employed in manufactured solar heat collection apparatus.
HVAC industry principles are widely known as a vital contribution to human comfort. A building structure utilizes heating, ventilating, and air conditioning (A/C cooling) HVAC systems for environmental comfort. HVAC systems comprise air conditioners, coolers, furnaces, air filters, and heat exchangers to gather outside air for heating or cooling using such system components that include HVAC ducts and diffusers (register vents). Various HVAC technologies include air movers that operate by methods of constant velocity, velocity reduction and equal friction. Artificial means of producing heat energy is the major method used in HVAC space heating systems.
Use of solar heat energy has yielded to that of artificial heating devices due to the sporadic nature and uncertainty of the sun's energy to provide a consistent and useful amount of heat. Sufficient solar energy for heating purposes is available only in certain geographic regions. It is therefore necessary to isolate solar energy as a source of heat using solar mapping for specific geographic locations (solar zones) that can best take advantage of such heat for space heating to the fullest extent possible. Solar maps illustrating solar energy potential by geographic region are available from a variety of publishing sources including that of the U.S. Department of Energy (1 U.S. Department of Energy [DOE], 2015), Solar maps derive from solar energy measurements recorded over many years to illustrate suitability for space heating at precise locations of earth's longitude and latitude.
Solar energy for heating, referred to as solar insolation, has for many years been measured by instruments in various geographic locations on earth with the intent to promote such solar energy as a source for optimum use primarily to heat domestic water and swimming pools. Solar energy is also widely used in generating electric power by employing photovoltaic apparatus. Use of solar heated air contained within a building attic has been the subject of a number of U.S. patents referenced in present art, as discussed herein, with a variety of apparatus and methods proposed for space heating using novel building structural designs or unique apparatus design concepts. Solar energy makes contact with building structural materials through the process described as solar insolation (solar heat absorption), resulting in significant heat measured as Btu per square foot of roof surface generally measured over an hour of time. The solar insolation is measurable for its intensity as determined by the angle at which the solar rays land on the surface of the earth and building structures. Solar insolation contributes to thermodynamics of heat transfer, which includes the principles of conduction and convection. Solar heat conducting through the roofing material into the attic or upper crawl space reaches the air to start convection causing heat to spread throughout the molecules of such air contained therein. The attic air in communication with the attic ceiling and adjacent material surfaces results in transfer of such solar heat as Btu measure that can vary with a building's elevation, location, weather conditions, and solar exposure. The attic air temperature, influenced by thermodynamic activity of the sun, must be high enough that when transported through an HVAC duct network is able to increase temperature in the habitable or working interior of a building structure as space heating.
Attic heated air, influenced by solar radiation differentiates from an HVAC system that generally utilizes fossil fuels, wood, or electricity. Solar radiation classifies as a passive source of heat having significant Btu content that can be absorbed into a building structure's roofing materials. Passive solar radiation also enters through windows to heat building interior air and its material contents. Solar insolation is enormous heat energy described as “solar cooking” by the United States National Aeronautics and Space Administration (NASA), applying this term to solar heating devices. NASA has conducted solar monitoring studies over many years to measure solar energy for all types of solar applications. NASA retains solar insolation historical data that is easily accessible on the internet covering most regions of the United States (2 National Aeronautics and Space Administration [NASA], 2015). Solar energy by sunlight from space in raw form is termed ‘solar constant’ when recorded at high altitude above the earth's surface. However, the solar energy constant loses much of its power after traveling through earth's atmosphere then landing on the surface at the geographic location of a particular building structure. NASA, and other monitoring agencies collecting solar insolation data, provides illustrated maps that help visualize solar energy intensity for locations in the U.S. where a heating system that relies on the sun would perform well.
Devices and methods for use of solar energy that have been invented over many years are typically placed external to (rooftops, walls, etc.), or incorporated within building structure assemblies. There are many U.S. patents relating to this technical field that apply solar energy for space heating using very diverse modes and applications. Examples of such applications in this field are those that incorporate solar collectors filled with water or other liquid to capture solar heat; water is a very good retainer of heat. Other examples incorporate structural designs within buildings to gather solar heat contained in receptacles or materials for later use. Other example applications include unique apparatus designed to exchange heat by employing materials and methods that concentrate the solar heat for use in space heating of a building. The diversity of apparatus and methods within this technical field appears in the related art discussion that follows.
BACKGROUND OF THE INVENTIONMany U.S. and foreign patents within the related art referenced herein propose the use of solar energy to heat swimming pools or to heat domestic water; some employ apparatus within the attic while others use external heat collection apparatus. Many patents of the related art disclose systems and methods incorporated within a building architectural design to include certain novel approaches for circulating solar heated air through apparatus or assemblies within the building structure. Other examples of systems and methods use solar heat transported within their proposed apparatus through built-in structural elements that require modifications to an existing building structure or that would become attached to an existing building structure. Some patent designs disclose apparatus to collect and contain the heat transferred through heat exchangers incorporated within the apparatus. Two heat exchange examples are: (1) a solar heating method known as a “recuperator” that makes use of a counterflow method to recover normally wasted heat, and (2) a solar heat exchanger for heating building structures termed “transpired solar air collectors” (TSAC), a system of unglazed solar collectors made of perforated metal or composite through which ambient air passes to becomes preheated for mixing with artificially heated air for transport into an HVAC supply duct.
Related art patents, listed chronologically as to approval dates, are discussed below. The list includes patent claims that use solar radiation for both water heating and space heating, while other patents focus only on space heating as the primary objective. The related art referenced herein includes those that employ attics as well as those that use exterior or interior mounted apparatus to capture solar radiation. Solar heating of water is also mentioned for purpose of describing a method that operates like a steam or hot water radiator, as a space-heating appliance, using a radiator coil or grid to radiate heat obtained from the attic. The related art so cited indicates somewhat slow improvement in technological advances. Many related art solar heating apparatus as cited herein are not widely marketed beyond those most commonly used for solar water heating. The references made herein are necessary to bring into focus the viability of the present invention's economic benefit of use compared to other present art apparatus and methods, as particular to solar space heating.
Pyle, U.S. Pat. No. 3,902,474 (September 1975) discloses a thermal glass covered box used for collecting and converting solar heat contained within a series of airways located inside the box. The airways contain conductive material colored black, able to hold heat better than other colors of material. The heat so contained in the airways moves by fan or pump for end use in building space heating, or for other heating uses.
Heilemann, U.S. Pat. No. 4,000,851 (January 1977) discloses an exterior mounted collector plate filled with domestic water located above an insulated ceiling for conducting heat into a layer of rocks located underneath the building structure. Such rocks are the heat energy reservoir facilitating transfer to a heat exchanger for building space heating or for domestic hot water needs.
Granger et al., U.S. Pat. No. 4,051,999 (October 1977) discloses a translucent roofing material used to allow solar radiation to be intercepted by a black in color solar thermal collector mounted inside the attic of the building for heating air. The heated air is transported by means of ducts to a thermal storage chamber located below the bottom floor, or underground, with such heated air used for space heating of the building interior.
Zornig, U.S. Pat. No. 4,103,825 (August 1978) discloses a solar heated and cooled dwelling employing plenums to gather heated air from an attic divided into upper and lower cavities. The upper attic cavity contains the stored heat as the lower attic cavity transitions the air exchange into the upper cavity. This system enables space heating during cold weather while gathering cooler air for reentry to the attic for reheating. Additionally, the system enables cooler air to enter the lower attic cavity to reduce heat in the immediate ceiling area of the building for a cooling effect during hot weather.
DiPeri, U.S. Pat. No. 4,122,828 (October 1978) discloses a solar energy heat collector for holding heated air in columns incorporated within building structure joists and wall assemblies. The system makes use of materials inside the collector that exhibit the ability to retain high specific heat in such materials for effectiveness in heating air for interior space heating and clothes drying.
Johnson, U.S. Pat. No. 4,173,304 (November 1979) discloses a double-walled structure that collects solar heat with air being the heat transfer medium to be stored in a subterranean gravel pit. This patent expresses the advantages of the system for space heating while noting that energy costs of pumping air is very small compared to the value of heat saved. The claims of this patent discuss the storage of heat underground that requires trenches to be prepared with sufficient protective measure to ensure containment of heat from the outside elements including rain and snow conditions. Additionally, the disclosure notes that preparation requires trenching to incorporate a concrete protective perimeter built in place for the gravel pit.
Awalt, Jr., U.S. Pat. No. 4,143,705 (March 1979) discloses solar collector panels filled with domestic water to gather radiant heat for transfer to a storage system. The storage system is able to contain heat and/or cold liquid for transfer through a network of coils with such heat or cold meeting with air for supply into the building interior. Such storage system requires a cooling tower and auxiliary boiler to supplement cooling and heating of a building structure.
McCullough et al., U.S. Pat. No. 4,262,657 (April 1981) discloses a solar air heater with a transparent front wall containing an inlet and outlet to move air that is heated through a porous radiation absorbent collector plate of a honeycomb shaped cellular structure for capturing the solar heated air.
Zebuhr, U.S. Pat. No. 4,263,894 (April 1981) discloses a solar collector comprising a glazed roof with light pervious surface directed southerly (in northern hemisphere) for application during the heating season. Such collector gathers sunlight focused on its light impervious surface inside the attic with the resulting focused heat rays of the sun directed to an HVAC duct pair also inside the attic. The HVAC duct pair contains air starting at ambient temperature until the sun's presence causes heat to focus on such ducts with the resulting heated air transferred by blower to a heat exchanger. The heat exchanger then becomes the heat medium to be used for space heating. The invention addresses summer time conditions utilizing the HVAC duct pair for ventilation of the building attic.
Hummel, U.S. Pat. No. 4,323,054 (April 1982) discloses a solar energy collection system for a building employing a solar absorbent surface exposed to the sun through a glass exterior surface. The glass exterior surface covers sheet metal to contain heat in passageways with solar heated air circulating to cause convection of heat in an air-liquid heat exchanger. This system resides on a south facing wall of a building to capture maximum wintertime solar rays. A conventional hot water radiator system couples to the heat exchanger, which in turn connects to the solar energy collection system by ductwork.
Misrahi et al., Canadian Pat. No. CA 1,179,565 (December 1984) discloses a solar heating system including a radiant heat collector of glazed panels mounted upstanding along a building wall (south facing in northern hemisphere and north facing in southern hemisphere). The heat collector contains a heat storage metal core painted black with such paint being a mixture to include sand that roughens the core surface to enable the multiple facets on the sand to increase absorption of solar heat energy with greater efficiency. The system collects fresh air for heating using a heat storage core, which results in heated air transporting upwards to ducts used for building space heating. This patent is the reference for the SolarWall® product discussed below.
Fleishmann et al., U.S. Pat. No. 4,378,785 (April 1983) discloses a solar heating system used for water heating as well as for space heating and cooling. The system utilizes the attic to supply heat through a glass window of the building roof to admit the high grade of sunlight heat for movement to a remote heat reservoir used for heat transfer. A heat pump is employed with refrigerant coils and piping to extract low grade heat from the air spaces available including that of the building interior and the attic.
Smith, U.S. Pat. No. 4,502,467 (March 1985 re. 32,607—February 1988) discloses a mounted solar heating pack assembly for installation inside an attic to gather solar heated air for delivery through a plenum supplying a plurality of flexible ducts with the heated air exiting at ceiling mounted diffusers. A cooling only ventilator thermostat in the attic and a heating only thermostat in the building interior manage operating control.
Schmitz, U.S. Pat. No. 4,741,391 (May 1988) discloses a method and apparatus for recovering transmitted heat. This system uses a wall structure of two hollow spaces in parallel to each other in which the outside ambient air is gathered. Air pressure within the system allows heating or cooling of the air with the inner hollow space used to retain the resulting air mass. The system is connected either to a heating system of a building, a heat storage unit, or directed to the atmosphere.
Palmer, U.S. Pat. No. 5,014,770 (May 1991) discloses an attic based air to liquid forced air heat exchanger for use in heating swimming pools and domestic water. The exchanger mounted internally inside an attic, promotes its novelty as being an improvement over externally mounted solar collectors.
Christensen et al., U.S. Pat. No. 5,692,491 (December 1997) discloses an unglazed transpired solar collector (UTC) using solar radiation to heat incoming air for distribution, comprising an unglazed absorber of low thermal-conductance material to receive incoming ambient air for heating as it passes over the absorber surface. The heated air moves by suction through the perforated absorber material fabricated with tightly spaced holes for the particular air heating use.
Noah, U.S. Pat. No. 6,533,026 (March 2003) discloses a heat removing system utilizing the roof of a building as a solar collector. A heat barrier material is secured to the inside of the attic ceiling in an isolated form on the free edges of roof rafters to reflect radiant heat into air flow passageways formed between the rafters. This system uses two blower coil units to harness the solar heat absorbed by the roof material. The system retrofits to an existing heat pump for normal operation to heat domestic water. This system promotes the novelty of using the attic as the solar collector compared to disadvantages of externally mounted solar collectors.
McClendon, U.S. Pat. No. 7,677,243 B2 (March 2010) discloses a solar heating system for buildings to include solar collector panels bounding a plenum enclosed in a structural container to collect solar radiation for space heating. The system architectural structure bears similarity to an attic containing a plurality of metal sheets formed into a panel structure to collect the solar heat with such structure placement being on a building roof, at ground level, or independently elevated.
Hamby, U.S. Pat. No. 8,152,608 B1 (April 2012) discloses a solar energy intercept and waste heat recovery system design to be incorporated in new or retrofit building construction. The objective of the design is to incorporate natural ventilation including use of heated attic air to reduce the high cost of artificial heating and cooling. The natural ventilation design intercepts unwanted heat and diverts it to the outside before entering the building interior thus aiding cooling in hot weather. The design further addresses utilizing trapped heat during cold weather for heating a building.
Roseberry, U.S. Pat. No. 8,776,780 B2 (July 2014) discloses an attic ventilation and heat recovery device for warming swimming pool water and can be made to work as a domestic water heater. This device employs an air to water heat exchanger that also performs attic ventilation in order to reduce the cooling load during summer. This system uses heated air from within the attic space gained by solar insolation on the roof surface. The system incorporates a blower that sends a stream of hot air from the attic through the heat exchanger mounted on the roof to heat the water supply for transport downward to the swimming pool.
Hagg, U.S. Pat. No. 8,833,362 B2 (September 2014) discloses a heat recovery installation using solar energy collected in a three-channel plate mounted on a roof. The three-channel plate performs heat exchange by using fresh air that becomes heated to very high temperature captured between the plates for heat storage during winter. The recovery installation is also able to collect and store cool air for summer use. The recovery installation relies on a storage medium of water to be contained under the building with cold water stored for summer and hot water stored for winter. The patent claims the system to be much more efficient than that of current solar collectors. The collector modules may use varying design features to include fins, perforated segments, and moveable elements in axis to the solar radiation.
MacKay et al., U.S. Pat. No. 8,863,741 B2 (October 2014) discloses a solar air heating module using conical solar collectors protected by a film cover on the front and back sides to prevent air from escaping from entrance to exit, thereby enabling solar heat to be retained therein to avoid negative effect of wind. The solar collectors are adjustable to follow the sun's seasonal angle path movement, or fixed into position. This solar heating module may also be used to transport liquids for heating.
Researching related art patents and their applicability in commerce, as of this writing, reveals a low number of apparatus offered in commerce. Some of the currently marketed apparatus employ embodiments as originally claimed while some show modifications to their original patent claimed features. Many related art patent apparatus referenced herein have no apparent adoption, or have shown limited marketing in commerce. Many of the patents are beyond their term of protection. The significance of this research is to illustrate marketability of patented related art products offered in commerce. The marketability of such related art inventions should also include a respectable economic payback for the consumer who would use these solar heating applications for long-term energy cost savings. The following discussion include some of the above referenced patents currently engaged in commerce by citing apparatus highlights and performance characteristics along with detail specifications and relevant information, labeled as Item 1 through Item 6 next.
Item 1. Canadian patent CA 1179565, the Misrahi and Deschenes patent of 1984, a solar air collector, acquired by Conserval Engineering, Inc. of Toronto Ontario Canada which introduced its first installation in 1990. This air collector apparatus is marketed as ‘SolarWall®’ defined in marketing literature to be a “transpired solar air collector” (TSAC) which makes use of unglazed solar collectors, a departure from the original patent which used glazed solar collectors (3 SolarWall®—January, 2015). The SolarWall® collector contains a perforated metal core through which ambient air is heated by solar radiation with such heated air passing into an existing HVAC network that is used predominately for industrial and commercial building heating and pre-heating applications. The TSAC SolarWall® product, successfully implemented in a variety of industries and building types around the world, has attracted major corporations able to afford the cost of such installation while such corporations focus on reduction of greenhouse gases. According to the company, the unglazed SolarWall® product performs as well as a glazed collector because of the method for capturing solar generated heat inside the metal perforated core to prevent thermal loss as ambient air flows past, however wind does affect its efficiency to cause some thermal loss. A great deal of planning is required to install a system such as SolarWall®, or that of other similar vendor products, and to do so involves much detail engineering or modeling prior to implementation. Cost of installation indicates economic payback can be up to 20 years, depending on location, although some studies have shown reasonably good payback time. Economic payback time differs for originally installed or retrofitted installations, with retrofits generally more expensive by nature. The TSAC concept is suitable to northerly climates outside of more favorable solar geographic zones. SolarWall® has introduced a 2-Stage collector system, tested in 2012, constructed with the bottom portion unglazed and the top portion glazed to help reduce the effect that wind has on the collector performance. SolarWall® claims the 2-Stage collector achieves 25% or more efficiency than the completely unglazed version according to product literature (4 SolarWall®—February, 2015). SolarWall® product studies and performance results appear in the following five paragraphs labeled Item 1-A through Item 1-E.
Item 1-A. A study of the SolarWall® product was commissioned by Minnesota State University, Mankato, and The Office of Energy Security, Minnesota Department of Commerce, as amended Sep. 27, 2011, entitled ‘FINAL PROJECT REPORT Performance Analysis of Solar Walls in Minnesota’ (5 Tebbe, Moaveni, and Schwarzkopf, 2011). The study analyzed unglazed TSAC perforated collector performance at several installations in Minnesota during the 2008-2009 heating season. The study of vertically placed solar collector installations used a wide array of very sophisticated scientific measurement and testing devices. The study shows example findings as follows: (a) Economic results of performance in the northern climate location, having nearly 7,000 heating degree days (HDD) per year, would achieve between 9.2% and 19.0% energy savings for the tested buildings (5 Tebbe et al., 2011, pp. 15, 81, 86, 90). (b) The collector solar efficiencies are 30 to 55%, with the higher value occurring during cooler months (5 Tebbe et al., 2011, pp. 1, 15). (c) The collector efficiency is difficult to assess as indicated in this quote: “Studies from the National Renewable Energy Laboratory (NREL) predict overall efficiencies of 50% or higher, but only with careful design and operation.” (5 Tebbe et al., 2011, p. 5). (d) The issue of airflow through the collector appears in this quote: “The DOE spreadsheet assumes an ideal efficiency based on a 4 CFM/ft2 approach velocity. Therefore in most cases it will overestimate the potential energy savings (as noted in the Break and 3rd Precinct results.)” (5 Tebbe et al., 2011, p. 10). (e) The collector output at the test locations ranged from 30.1 Btu/h/ft2 to 65.0 Btu/h/ft2 against a best case value normally expected of 160 Btu/h/ft2 (a general rule used by manufacturers), with this statement made in the study regarding the actual output: “160 Btu/h/ft2 value should be viewed as a “best case” savings which is unlikely to be achieved.” (5 Tebbe et al., 2011, p. 16). However, one test site performance varied as in this quote: “This value was computed based on a partial heating season which was considered abnormally low” (5 Tebbe et al., 2011, p. 16 footnote 4); [End of items (a) through (e)]. Thus, from statements made from such study findings of the vertically mounted SolarWall® TSAC solar collector, performance of such collector degrades when placed in a fixed position as the sun's azimuth changes throughout the heating season. Further, the TSAC collector heated air can only be sucked in by the related HVAC fan in low volume due to the slow heat processing of ambient air coming in contact with the perforated core solar heat absorbing surface of the collector (SolarWall® literature claims 70% up to 90% efficiency with optimum conditions). Other findings indicate that solar efficiency measure of approximately 50%, as indicated in (c) above, would be the heat produced within the interior of the TSAC collector, however efficiency within the collector does not result in a 50% energy production delivered by the collector after it leaves the TSAC collector interior surfaces due to other thermal losses. The study findings also indicate a lower heat energy production is the result, as heated air sucked by the HVAC air mover moderates in temperature from wind velocity and any variation in effective solar insolation bearing on the surface of the collector during operation.
Item 1-B. The International Energy Agency (IEA) study entitled low Cost, High Performance Solar Air-Heating Systems Using Perforated Absorbers [Final Report of Task 14] September 1999’ (6 Cali et al., 1999), shows performance results of several SolarWall® projects, using the generic term “solar wall”. Installation of such solar walls occurred during the early 1990's at various commercial business, industrial, agricultural and utility facilities around the world using unglazed perforated collectors (TSAC). The study, involving a variety of collector configurations, shows mixed performance results. Tested installations were located in Canada and Germany, both countries challenged for adequate solar insolation. Some pertinent results of the study show the following: (a) the economic payback was disclosed for the General Motors assembly plant at Oshawa Canada to be 3.6 years compared to natural gas cost, and 1.0 to 1.3 years compared to cost using steam heat (6 Cali et al., 1999, p. 7); (b) the installation at the Ford of Canada plant, Oakville Canada declared all ventilation air is drawn through the collector with solar energy providing between 5% and 20% of the energy required to heat such ventilation air (6 Cali et al., 1999, p. 10).
Item 1-C. The Oregon Office of Energy reported on transpired solar collectors in central Oregon with an example 1,800 sq. ft. collector costing $19,800 and producing 150,000 Btu/ft2 for a heating season output of 270 million Btu, or about 2,700 therms. The collectors produce energy cost savings of $2,880 per year for an eastern Oregon location. The payback without tax credits would be 7 years. The report shows adding tax credits and accelerated depreciation for businesses would result in a net 4 years payback. The reported data to support these results obtained from Conserval Inc., and the US DOE as cited in the report (7 Oregon Office of Energy, 2014).
Item 1-D. The city of Halifax in Nova Scotia Canada installed a SolarWall® comprising collector surface of approximately 3,000 sq. ft. for a retrofit project at the Dartmouth Sportsplex in 2014. The cost of this project, $104,285.96, required an additional $20,000 for modifications to HVAC duct and automation equipment (8 Halifax Regional Council, 2014). The projected annual savings was determined to be about $10,000 using the then current rate for natural gas. The payback for this municipal project would be about 12 years. This project demonstrates total materials and installation cost, as a retrofit using the SolarWall® system, to be approximately $35 per sq. ft. of collector area, without adding the cost of necessary modifications.
Item 1-E. A Journal Of Solar Radiation Energy [JOSRE] study report entitled ‘Solar Air Collectors: An Energy Efficient Technology for Commercial Buildings’, interviewed Mr. M. Maher, representative of SolarWall® products on Apr. 30, 2013, who disclosed that cost of installing SolarWall® for retrofit is approximately $25 to $30 per sq. foot, while a new installation cost is approximately $20 per square foot (9 Sewalk, Liston, and Maher, 2013).
In review of Items 1-A through 1-E above regarding solar wall modality, the efficiency of TSAC solar wall collectors is shown to be affected by wind speed, physical location of the solar wall, impediments to the solar sunlight, and inherent thermal heat losses. These performance issues determine the actual amount of heated air supplied by the collector system, including performance associated with suction of the heated air when drawn through the tiny holes in the perforated membrane of the TSAC collector. SolarWall® or similar collector products installed in fixed vertical position have limits as to solar efficiency when the sun's azimuth angle changes, which influences energy cost savings even in high solar insolation regions; a roof mounting method may improve results, but such mounting method is costly. The SolarWall® product potential to serve a large consumer market for a residential application involves costly installation, and the necessity of finding suitable building site locations for placement of the collectors. The heating performance from suction of heated air through the collector shows inherent thermal losses occurring within the perforated surface of the collector, including the wind effect. Performance data is demonstrated in a 2012 solar product certification test by “Solar Rating & Certification Corporation (SRCC)”, as substantiated in SolarWall® literature on a Temperature Performance chart, which concluded that a 2 stage high performance collector, with the top half 2nd stage incorporating polymer glazing and the lower half 1st stage being unglazed, will produce 289 Btu/ft2 of collector area operating at 1 CFM/ft2 rate of suction in a medium wind condition at temperature rise of 42.2° C. (76° F.) from ambient (10 SolarWall®—March, 2012). The TSAC testing by SRCC includes airflow measured at 1 CFM, 2 CFM, and 4 CFM per sq. ft. of collector surface area under conditions of low, medium and high wind situations. This 289 Btu/ft2 would be under ideal conditions using 1 CFM/ft2 rate of suction, with usable heat flowing through the collector affected by the solar azimuth throughout a heating season when vertically installed. In the example testing, at 42.2° C. (76° F.) temperature ‘rise’ at 50% efficiency, results in a net 145 Btu/ft2 at 2 CFM/ft2 airflow delivery in a medium wind condition thereby producing approximately 29,000 Btu/h from the 200 sq. ft. collector, even at this fairly high temperature rise. If temperature ‘rise’ is 25.0° C. (45° F.) as a realistic value, at the same medium wind condition operating at 1 CFM/ft2 airflow delivery, the result would be approximately 87 Btu/ft2 producing 17,400 Btu/h for the same 200 sq. ft. of wall area. Efficiency of the SolarWall® product using 2 CFM/ft2 of collector airflow rate and a lower temperature ‘rise’ of 25.0° C. (45° F.) in the collector internals [considered to be more efficient in harmony with the statement in the University of Minnesota study (5 Tebbe et al., 2011, p. 1 para. 4)], of the TSAC 2-stage high performance collector system is analyzed in the following paragraph.
This Inventor analyzed the SolarWall® 2-stage TSAC collector using a measure of 200 sq. ft. containing approximately 100 cubic feet of internal air volume. With optimum solar insolation the interior collector area of the panel might heat to approximately 93.3° C. (200° F.) temperature level, which would be 12 Btu/ft3 in air volume (based on enthalpy calculation at sea level using an example 30% relative humidity) within such interior air space of the collector. An airflow suction of 2 CFM/ft2 rate for the TSAC selected for this analysis has its basis in the SolarWall performance graphs. The 200 sq. ft. collector, sucking 2 CFM/ft2 at near peak efficiency, would draw 400 cubic feet of air multiplied times 12 Btu/ft3, resulting in 259,200 Btu/h assuming 90% solar efficiency within the collector. The calculation would be 400 cu. ft.×12 Btu/ft3=4,800×60 min×90%=259,200 Btu/h based on cubic foot volume of heated air gathered by suction (this is the volume of air sucked out over 60 minutes through the 200 sq. ft. collector). The collector would, at this high temperature be sucking 1,296 Btu/ft2 from the collector area (259,200 Btu/h÷200 sq. ft.=1,296 Btu/ft2). However, reduction of solar efficiency, due to thermal losses, fixed vertical placement, and solar insolation variation, affects efficiency by as much as 50% as stated previously. At an assumed net efficiency of 50%, the temperature would then become 37.8° C. (100° F.) with enthalpy calculated to be 2.6 Btu/ft3 volume of air with 30% relative humidity at sea level. At such assumed net efficiency of 50% with the resulting lower temperature, the collector would then provide 400 cu. ft. of heated air at 2.6 Btu/ft3 operating 60 minutes, which equals 62,400 Btu/h for the 200 sq. ft. collector or 312 Btu/h/ft2 of collector area. The testing results of the TSAC collector mentioned above demonstrate modest temperature rise with actual operating results more likely to be lower. Assuming a more realistic average of 26.7° C. (80° F.) collector internal temperature during the entire heating season, in an example computation for a building located 2,500 feet in altitude, at 30% relative humidity, a heat energy yield would be 1.794 Btu/ft3 in the volume of heated air using enthalpy calculation. Such heat content at 1.794 Btu/ft3 further assumes that an internal temperature rise would be a nominal but realistic 25.0° C. (45° F.) within the collector. Using 1.794 Btu/ft3 of heated air sucked through the collector at 2 CFM over 60 minutes, the resulting output is 215.28 Btu/ft2 or 43,056 Btu/h for the 200 sq. ft. area of the SolarWall® TSAC collector. With heat rising 25.0° C. (45° F.) to about 26.7° C. (80° F.) from an ambient of 1.7° C. (35° F.) in the above example, the temperature would be near that of an attic heated air space, thus resulting in performance of a TSAC collector and the attic air heat reservoir being somewhat equal. However, the cost of the installation is much higher for the SolarWall® product than for an attic oriented space-heating device such as the present invention. The example Btu calculations are derived from the Conserval Engineering, Inc. graph dated 2012 entitled “Temperature Performance for SolarWall 2-Stage with Wind Variance” converted from Watt/m2 to Btu/ft2 (10 SolarWall®—March, 2014). Certification No. 10001759 issued Oct. 22, 2012 supporting this graph data was performed by the Solar Rating & Certification Corporation (11 Solar Rating & Certification Corporation [SRCC], 2011). The SolarWall® product compares with other present art devices in Table 2 below using 1.794 Btu/ft3 from the collector internal temperature 26.7° C. (80° F.) as a standard for the comparison, with the main objectives of Table 2 to show ‘cost to performance and economic payback’ for all devices being so compared.
Item 2. U.S. Pat. No. 4,502,667, the Smith patent of 1985 (re 1988), a mounted solar heating pack located in the attic, is presently owned by SolarAttic Corporation. The patented apparatus marketed by SolarAttic as model BD465 performs space heating during autumn through spring months, and attic ventilation in very cold climates to reduce the ice dam effect on roof surfaces. The apparatus operates by using a blower to move heated attic air into an HVAC plenum distributing such heated air through four outlets attached to flexible ducts leading to ceiling diffusers that enter the building interior. The device scalability offers variations of three blower/fan options labeled with a different model number. The installation instructions for the device, as found on the company website, indicate a substantial number of steps are required to complete an installation. The device has certain exclusive product features promoted as a turnkey system approach with somewhat complex operating procedures indicated within the literature. The HVAC components used by SolarAttic include flexible ducts and small diameter orifices that are of the type that can lower performance due to airflow friction and air pressure when delivering heated air to the desired location; this is important when considering the restricted daily attic heated air available. Researching the product for commercial success indicates that there is limited acceptance in the marketplace for this device currently. The device was recently discontinued for sale per the SolarAttic website (12 SolarAttic Corporation, model BD465, 2015).
Item 3. U.S. Pat. No. 5,014,770, the Palmer patent of 1991, is an attic-based air to liquid forced air heat exchanger used for heating swimming pools and domestic water. SolarAttic Corporation promotes and actively markets this heat exchanger under the designation model PCS3, as of 2015. The company claims solar heating of swimming pools save expensive heating costs by using non-polluting solar heated air from the attic rather than making use of liquid filled rooftop mounted solar panels. SolarAttic promotes the device as able to heat the swimming pool as it cools the attic thereby also reducing air conditioning costs in the process. This design specification indicates 20,000 to 150,000 Btu per hour of heat transfer. The device weighs 163 pounds dry and requires 20 pounds of water when operating; such weight acceptable in most engineered building attic structures. This device typically operates at 40 to 50 gallons per minute of water flow (13 SolarAttic Corporation, model PCS3, 2015). This device meets with challenge in the Roseberry patent (item 4 below) indicating certain deficiencies and problems, such as potential for water leaks in the attic area.
Item 4. U.S. Pat. No. 8,776,780, the Roseberry patent of 2003, is an attic located ventilation and heat recovery device for warming swimming pools or for heating domestic water. This patent claim references the Palmer U.S. Pat. No. 5,014,770 (May 1991) as discussed above noting deficiencies of the Palmer system to that of the Roseberry patent citing claims of a less troublesome installation and the elimination of any potential major water leaks that could occur inside the attic. The Roseberry apparatus mounts at a rooftop opening to pull attic-heated air through the device, while offering better control of temperature at the supply side of the system. This patented device is currently offered in commerce designated as WarmSpring™ attic heat recovery system. Heated attic air drawn through the opening of the building roof structure crosses over a water-filled copper pipe coil heat exchanger to heat water for domestic use or for swimming pools. The WarmSpring™ vendor claims 250,000 Btu/day can be available from this system, primarily used as an auxiliary heat source. The claimed Btu/day output seems reasonable for certain warm climate locations by using a large ventilator fan to blow hot air across the heat exchanger assembly to heat swimming pool water. A ventilator fan that produces 400 CFM airflow, as an example, would result in about two Btu per cu. ft. of air, on average, in warmer climates throughout the heating season and much greater in cooling season. At 2 (two) Btu/ft3 in the airflow the 400 CFM fan would transport 48,000 Btu/h across the coil assembly producing the claimed 250,000 Btu over 5¼ hours in strong sunlight, assuming the Btu measure can be contained long enough as it moves over the coil assembly. Heated air passing quickly by the copper coil assembly may be subject to thermal losses into the atmosphere thereby reducing efficiency. The WarmSpring™ device is suitable for warmer climates where swimming pools are common. A typical residential attic containing 5,000 cubic feet of airspace, would likely hold sufficient heat during the early to late afternoon to perform the claimed heat output. Research of the WarmSpring™ product does not indicate any major market distribution channels at present (14 WarmSpring Pool Heating, 2015).
Item 5. U.S. Pat. No. 8,833,362 B2, the Hagg patent of 2014, is a heat recovery installation using solar energy collected in a three-channel plate mounted on a roof Innovy-Energy Innovations of the Netherlands presently markets the apparatus as Recusol™ (15 Innovy-Energy Innovations, 2015). Water is the heat storage medium in the Recusol™ apparatus. The Recusol™ apparatus was extensively tested in housing units in the Netherlands over a 6 years period (2001-2007) using 214 sq. ft. of collector costing approximately $15,000 per each standard family house as tested. Recusol™ is an HVAC recuperator, defined as a device that can process waste heat for reuse in a heating system at a high efficiency of heat retention while also gathering heat from sunlight. The collector design is a counterflow principle device. The test buildings are located in De Bilt the Netherlands at 13 ft. above sea level and 58° N,5° E (latitude, longitude) equivalent to Juneau Ak., USA latitude with de Bilt experiencing 221 days in a typical heating season at the location. There is about 4,500 heating degree days during a heating season with average high temperature of 22.2° C. (72° F.) and average low temperature about 0.0° C. (32° F.) at the test location. The Recusol™ product indicates 50% solar efficiency of the collector with 40% coming from solar and 10% from waste heat recovery. Overall heat collected by the product is made from assumptions and predictions using a 1/65 scale model for testing by Hagg (16 GreenIdeaLive, 2009). There is no current distribution of the Recusol™ product in commerce as of this writing.
Item 6. U.S. Pat. No. 8,863,741 B2, the MacKay patent of 2014, is a solar air-heating device using solar energy similar in manner to the SolarWall® TSAC design. However, the MacKay patent cites a number of features as improvements over a TSAC design, including a plurality of sections chained together to enable the collector to be rolled into itself for storage. The collector internals handle both fluids and air (or gasses). Individual collector sections can be adjustable (automatically or manually) to follow the sun's season and latitude angle path to increase solar heat gathering efficiency. The MacKay patent claims superior performance to prior art and exhibits a number of heat capturing design elements including tapered fins on cylinders that are efficient for solar heat collection. This U.S. patent is presently the basis for products offered by Solar-Infra Systems International Ltd. of Surrey BC Canada (Solar-Infra), which markets a solar window mounted panel. Solar-Infra Model SIS C59M 2448, measuring 22″×48″×2″, is glazed with thick clear polycarbonate having potential heat energy output of 950 Btu/h/sf collector area. The space heating output is approximately 7,600 Btu/h or about 6.33 Btu/h/ft3 in an area of 150 sq. ft. With 8′ ceilings assumed, for a 150 sq. ft. area or 1200/ft3 of building interior air volume served, such output is equivalent of a small electric heater. Such apparatus is placed vertically on the inside of a window to capture sun from due south in the northern hemisphere and from due north in the southern hemisphere. Company literature claims 5.11 million Btu over 9 months of use with the panel tilted vertically facing a southerly direction (northern hemisphere). This collector claims to absorb 80% solar radiation using a polycarbonate panel with 16 solar collector cells per panel. An integrated PV panel producing 20 watts at 18Vdc drives a speed control fan at 50-87 CFM. The device construction method makes use of UL94V-0 plastic on the panel weighing 24.7 pounds to enable hanging the device over an interior window on the inside. Solar radiation data per the specifications is from RETScreen.net calculator at location 49N latitude, 123.1E longitude employing NASA solar insolation data using 80% of solar insolation at 32.2° C. (90° F.) vertically installed behind a window over 9 months (September through May). The Underwriter Laboratories certified the collector for fire safety as self-extinguishing conforming to window and wall covering building standards. The system requires a converter (110Vac to 18Vdc) to switch power for the fan when the sun is not sufficient for PV cell charging. Solar-Infra currently markets the collector on the internet as of this writing. The Solar-Infra literature indicates this panel would serve an interior area of 150 sq. ft., about the size of a small bedroom (17 Home Depot—January, 2015). The Solar-Infra collector was recently priced at $316 indicating dimensions of 47.75″×23.75″×2.375″ for the product (18 Home Depot—February, 2015). The cost of $316 for one collector panel (8 sq. ft.) would translate to $3,160 assuming 10 collectors are required for a standard home of 1,500 sq. ft., depending on sufficient southerly window exposure of at least 800 sq. ft. of glass area.
Non Patented Item 1, the U.S. Solar Heating model SH27 mounted solar air heating panel is designed to produce 4,500 Btu/h by small fan blowing from the panel into a room through an HVAC duct. The solar air-heating panel is an 8′×3′ rectangle 5″ thick weighing 70 pounds, containing a fan producing 90 CFM. The heated air in this panel would rise to 54.4° C. (130° F.) in temperature. Approximate cost is $2,014 for a 24 square foot panel (19 U.S. Solar Heating, 2015).
Non Patented Item 2, the SunMate™ hot air solar panel, is manufactured by Environmental Solar Systems, Inc., Methuen Mass. USA. The SunMate™ model SM-14 uses a heat absorber plate accessed by fan when reaching 43.3° C. (110° F.), shutting off at 32.0° C. (90° F.) internal temperature. This apparatus measures 77″×35″×4″ weighing 90 pounds and is to be mounted on a roof or exterior wall. This unit contains a 100 CFM 12Vdc 7-watt fan. The SunMate™ panel has a corrugated aluminum heat exchanger with black coating to collect the solar rays. The device uses polyisocyanurate foam board insulation (commonly referred to as polyiso) to retain the heat. Polyiso is a rigid foam product, with an R-value of about 6.0 for each inch of thickness, commonly used as insulation in many solar heating collectors. Solar Rating & Certification Corporation (SRCC) certified model SM-14 as an OG-100 certified solar collector, and the model has received an Energy Star® rating to validate its ability to qualify for solar tax credits. The SunMate™ uses a step down transformer from 120Vac 60 Hz to a 12Vdc 7-watt operation when a discrete 12Vdc source is unavailable. The SunMate™ panel can heat about 750 sq. ft. of area (20 Environmental Solar Systems Inc., 2015). The product was offered at $1,495 for the 4″×35″×77″ panel marketed on the internet at altestore.com as of this writing (21 AltE Store®, 2015).
In summary, the various marketed devices described above require substantial investment cost to obtain adequate energy cost savings when comparing such referenced solar collector devices to that of the present invention attic placed apparatus. Comparison of the above devices appears in the Advantageous Effects of Invention section herein on Table 2, with such comparison focused on investment cost relative to energy cost savings performance. The comparison made in Table 2 includes specifications and data as published by each of the device manufacturers referenced. The comparison does not challenge solar energy performances of each product, expecting that each device can stand on its own merits for being acceptable in the marketplace. The principal objective of Table 2 is to determine affordability and energy cost savings as the primary concern for marketability. Comparison of the devices on Table 2 assumes internal temperature constant of 26.7° C. (80° F.) at 30% relative humidity located at 2,500 feet altitude for all devices. Table 2 assumptions fairly compare Btu output computed from data specifications as provided by the device manufacturers. The above apparatus and methods marketed to consumers illustrate the variety of solar space heating products or attic oriented heating appliances offered. The performance of the solar collectors and space heating modalities described above offer support for the present invention apparatus and methods to serve as a viable and credible alternative for solar space heating in locations where suitable. The present invention is able to utilize the significant volume of heated air contained within an attic space efficiently when employing methods discussed in the SUMMARY OF THE INVENTION section under Advantageous Effects of Invention.
Technical ProblemsTechnical problems associated with present art normally focus on the physical and operational methods directly attributed to the apparatus. However, there are other important technical problems occurring outside the realm of physical and operational attributes for consideration when addressing a solar energy system. Some very important problems to address in present art apparatus are the attributes of efficiency, cost effectiveness, complexity, and ease of use. The aforementioned attributes also relate to physical or technical problems when addressing utility of the apparatus and its methods of operation to achieve a necessary energy cost savings benefit for the user. Utility patents apparatus and methods should provide economic benefit for the user and profitability for the manufacturer or vendor for product success in commerce. However, many of the prior solar energy patents issued have had limited success following many years since their invention, which is a manifestation of the technical problems mentioned herein: efficiency, cost effectiveness, complexity or utility, and ease of use. The various patents referenced above demonstrate that even excellent well developed apparatus lack acceptance in the marketplace either for being too complicated or too expensive without providing substantial investment payback; this applies to even recently approved patents. Failure of an apparatus or system to offer perceptible enablement and utility is a problem in related art just as much as its scientific or technical shortcomings. The effective utility of present art patented devices are generally superseded by later technology with better designs, but even newer designs show lack of acceptance in commerce. Current solar energy systems have economic advantages and disadvantages whether it is a system's cost to performance or the length of time required to recover the investment cost. Solutions to technical shortcomings mentioned require devices of related art to be truly superior at gathering heat energy. To measure the effectiveness of an invention is to examine its acceptance as a readily marketable and viable concept for adoption within the economy and to overcome enablement problems discussed herein.
Technical problems of a physical or mechanical nature, typically encountered in solar energy systems, involve employment of complex scientific principles coupled with unique apparatus and operational parameters for harnessing solar energy for its most efficient use in comparison to other energy producing devices. Much effort by inventors has been to increase the yield of heat or electricity gathered from solar energy through their creations in comparison to prior art, facing obstacles in their endeavors. The selection of materials to retain heat continues to be a priority, which is a major technical issue, especially since many materials that exhibit the potential to improve the art are in short supply or have become very expensive such as rare earth substances that contain important molecular properties necessary for technology improvements.
Technical problems evident within the solar energy development field have amplified in recent years by the quest for “green energy” which has become a mission for inventors who desire to accelerate the technology and increase productivity of solar energy devices in order to replace the use of existing carbon and greenhouse gas polluting fuel sources with clean energy sources. Improvements in solar energy performance are slow to develop as witnessed with the currently available commercial solar products offered. Many of the “green energy” applications have not substantially improved solar energy technology or efficiency beyond prior art due to limitations of the science and the type of materials available. As witness to such limitations, solar electric generation has achieved only modest gains from chemistries and methods necessary to improve output of electricity in kilowatts per square foot of a panel area, while improvement in solar heating methods and technologies are also quite modest. However, as more attention focuses on “green energy”, solar applications have become more widely accepted, and desired by consumers. Further, the spirit of green energy applications helps to promote protection of the earth's fragile ecosystem while reducing ‘carbon footprint’ or greenhouse gasses (GHG). Additionally, it is important to consider that green energy applications such as PV panels will be in competition for available solar insolation when there is a desire to install other rooftop collectors used for solar water heating and/or for solar space heating.
Along with increasing interest in the use of solar energy, the acquisition cost of the various apparatus used in solar applications must deal with blending of new advances in technologies to that of existing technologies that have proven to work reasonably well. The technical problem here is to avoid new inventions detracting from or making obsolete a present art device, prohibiting employment beyond the present art device expected useful life before realizing full economic value. Green energy improvements in technologies should consider the existing performance of a currently installed apparatus that still achieves good economic payback as older technology continues to offer value for the user without additional investment. A solar device may be a superior investment in the long term once fully realized for its investment savings payback as the device continues to produce long-term savings benefits until faced with major maintenance or renovation. Of course, the decision to make a changeover to newer technology will rest with the consumer's wants, needs and their available finances.
It is important to recognize economies of scale using solar energy devices to meet user affordability as well as to help increase adoption of the technology. Cost of solar equipment becomes a major issue when engaging with consumers, be they individuals or businesses, when affordability is a key issue. The apparatus design and operation must be of a concept that creates interest and can demonstrate methods that would convincingly deliver good results while being readily adoptable and affordable in commerce. To promote an apparatus design as affordable necessitates modern manufacturing methods to produce the device cost efficiently. The device manufacturer should be able to produce a high volume of the apparatus to meet an economic price point that would be affordable for most consumers. Even with relatively long-term payback of investment in a solar device, the adoption of such device can have varying degrees of acceptance due to its perception of initial affordability. The actual cost to the performance of such device influences a decision to go forward with purchase and installation. The affordability of such a device should influence the buyer even while other traditional sources are equally economical and fall within the given budgetary constraints of the prospective end user.
A technical problem that requires analysis beyond the studies referenced herein involves management of multiple ‘state of the art’ apparatus where a good magnitude of solar energy is available; it therefore being advantageous to have more than one solar modality placed on a building roof structure. A roof covered with solar panels used for heating a swimming pool usually cannot accept a photovoltaic (PV) electricity generating system simultaneously, unless integrated into the system. However, where there is a desire to employ other solar energy modality on the same roof structure, while using attic air space for heating for example, one must expect some degradation of performance caused by such other type solar device placed on the rooftop. Some recent solar energy studies have focused on PV installations that inhibit transmission of the solar radiation long waves, the primary source for solar heating. Such long wave radiation is important if inhibited from absorption by roofing materials for adequate conduction of heat into the attic ceiling resulting in insufficient heat for space heating. The following paragraph discusses a study of this type of technical problem.
A recent study in 2009 conducted at the University of California San Diego, San Diego Calif. USA, analyzed solar heat entering through a building ceiling. The study focused on sunlight blocked by PV panels mounted either flat or angular to the roof. The study entitled “Effects of Solar Photovoltaic Panels on Roof Heat Transfer” involved PV equipment installed on the flat roof of a warehouse building (described as a hollow cube building) located at the University (22 Dominquez, Kleissl, & Luvall, 2011). The study summary discusses the effect of PV panels covering the rooftop resulting in lower solar heat absorption through the building ceiling, depending on placement of the panels as either flat or angular to the building roof plane. The study cites elemental thermodynamic influenced heat retained under the surface of the PV panels with such heat remaining after sundown, which can then contribute to the slowing of the building heating load during the heating season. Upon review, the study documentation focuses on how heat load in heating season months becomes less affected than in cooling season months due to the sun's azimuth as directed toward the solar collectors. Table 1 below is an excerpt from the study to show the amount of heat, in watts per square meter, as measured on the flat roof area just below the PV panels as well as the same measurement of heat on the exposed (uncovered) flat rooftop, during the entire 12 months period of 2009. Table 1 illustrates the heating load during heating season months as having only modest reduction with PV panels in place versus cooling season months. The last column in Table 1, inserted by This Inventor, shows the variance between the heating load on the covered roof and uncovered roof during the 12 months. The study highlights that heat energy can be adequate for heat transfer through the roof during heating season, demonstrated by low variability of heat loss between the exposed roof and the PV covered roof. This study yields information that should encourage the implementation of the present invention use of attic heat for space heating regardless of PV panels employed on a rooftop. This referenced study and its analysis shows feasibility of a partnership between solar electric applications and attic solar heating applications, although this may result in some sacrifice of performance of the secondary attic solar heating apparatus.
In conclusion, the collaboration of a plurality of solar energy modes would require a balanced approach to optimize every possible component of solar radiation energy at its fullest shared potential, thereby avoiding conflicts from such sharing when employing the present invention apparatus for use of attic heated air.
Technical problems associated with solar heat energy are also evident in the selection of suitable roofing material types and their colors that would increase potential for conduction of the solar heat entering directly through such materials into the attic structure, even with PV panels mounted on the rooftop. However, water heating solar collectors located on rooftops are likely to present more of a challenge for conduction of heat to the attic regardless of the type of roofing materials in place. Heated water moving through the solar collectors to a swimming pool or domestic water heater will reduce the rate at which heat transfers into the roofing materials from the underside of the collectors. However, if the water flow slows or stops during the heating season, a portion of the remaining heat adhering near or on the roofing material will conduct into the attic at varying levels to the benefit of attic space heating modality, providing sufficient heat for conduction and convection into the attic air space. Swimming pool solar collectors are considered low temperature collectors with high thermal losses according to the North American Board of Certified Energy Practitioners Certified Solar Heating Installer Study and Resource Guide; stating in their Section 4.1.1: “Therefore, they aren't capable of producing usable heat for pools during the winter in moderate or cold climates.” (23 North American Board of Certified Energy Practitioners [NABCEP], 2013). It is therefore likely that during the heating season the roof will be aggregating some of the cast off heat from the pool collector to benefit the attic as a solar heat collector and source of heat for the present invention.
Technical problems occur with present art solar heat collectors such as SolarWall® perforated TSAC panels when measuring efficiency for space heating. The SolarWall® TSAC panel is stated to reach 93.3° C. (200° F.) or above while attaining solar efficiency of approximately 50% according to test documentation. SolarWall® claims 70% up to 90% solar efficiency of the collector as stated in the SolarWall® literature as mentioned above. Even with the significant heat on the surface of the collector, it does not realize its full potential for the intended purpose. The TSAC solar panel net yield of usable heat is compromised by a number of factors: (1) ambient air temperature, (2) wind conditions, (3) sun's azimuth (time of year) relative to panel placement, (4) velocity of the air moving through the porous heated surface, (4) fixed position of the panels, (5) airflow rate during suction of heated air through the porous heated surface for transport to the task area, (6) type of materials selected for heat gathering, and (7) insulation material heat resistance rating suitable to retain such heat. Use of fresh ambient air or even waste heat flowing by suction of the TSAC moves through in a matter of seconds. The blower/fan leaves much of the heat inside the TSAC panel because it is subject to thermal losses as the cooler ambient air passes through quickly. The ambient air would not have time for the solar energy to heat the molecules of air sufficiently by convection because of the fast airflow thereby resulting in performance efficiency degradation within the collector's heating chamber. The aforementioned heat transfer problem is an issue with the TSAC collector products and other external mounted solar collectors compounded by wind conditions. Window mounted solar collectors can experience the same problem of heat transfer within the collector surface. It is important to note that good solar conditions govern delivery of usable heated air for any solar heating system along with suitability of the building and attic structure, and the actual day and month of the heating season.
A technical problem is evident with heat exchanger modality when using solar heated air. Molecules of solar heated air have much lower Btu content per cubic foot compared to water, thus limiting a heat exchanger's ability to hold heat for very long during the convection process. The heat level in the solar heated air also depends upon relative humidity level since dry air will have less Btu than moist air. In addition, the ambient air going through the HVAC system, drawn in by a blower/fan, is moving quickly through the heat exchanger with the lower ambient air temperature and the air velocity influencing thermal losses within the exchanger during this process prior to entering the HVAC supply duct. By comparison, a heat exchanger in an older natural gas furnace operates at about 79.4° C. (175° F.) or more, but the temperature of the heated air drops to about 32.2-37.8° C. (90-100° F.) by the time it gets to the building interior diffuser outlet which is manifested partially as duct heat loss and mostly as flue heat loss. A natural gas furnace efficiency can be as low as 60%, which is apparent in the aforementioned temperature drop; this is a common problem with older furnaces. A typical residential gas furnace provides about 1,100 cubic feet per minute of airflow with much of the heat wasted in the process by going directly up the flue resulting in 10% to 40% of the heat being lost, depending on the age and design of the furnace. It is important to emphasize that the burner box in a furnace is actually even hotter than 79.4° C. (175° F.) before the thermal losses within the metal structure of the heat exchanger. Regardless, any heat exchange meets with large thermal losses in a typical furnace. Meanwhile, a good percentage of artificially produced Btu measure escapes from the building interior upward into the attic. A portion of such heat loss is occurring through ceiling soffits and light fixtures built into the ceiling along with natural conduction through the ceiling materials.
A technical problem is associated with methods for transporting heated air due to the variety of thermodynamic variables at work in a natural environment including the position and intensity of the sun and related weather patterns. Weather and sun position make it difficult to compare results specifically to that of heating a building structure by artificial means using fuel sources such as natural gas or electricity. Present art methods that concentrate solar rays using specialized collectors, heat exchangers, or heat compression devices, fail to optimize use of available solar heated air efficiently as discussed above. This problem also associates with the size and mass of the equipment installed and the inability of fixed installations to track the sun.
Other technical issues involve the altitude (elevation) of a subject building structure location using a solar air-heating device. Altitude affects density of air molecules within the space heating system blower/fan, as it must move more air molecules at lower altitudes and less air molecules at higher altitude. A constant velocity blower moves a specific volume of air at a constant rate, but air molecule density will change based on temperature and air pressure; this also changes Btu measure. This circumstance does not affect the inherent static pressure and velocity pressure as much within HVAC components in place, but this can result in lower Btu measure output at a higher altitude due to density of air decreasing as altitude increases. Thus, lower air density provides more heat Btu per cubic foot in a building structure located at lower altitude such as at sea level. Recognition of air pressure relating to thermodynamics of natural gas supplied by utility companies requires an adjustment to the natural gas billing rate based on altitude location of the customer. Natural gas net heat content changes based on air pressure therefore requiring a billing factor by the utility company when invoicing the end user; the billing rate reduces as altitude increases to recognize such heat content variation. This heat content in air, given the altitude, causes efficiency and performance variations when using solar air heating devices in a manner similar to that of traditional heating appliances. Such heat content can be determined based on psychrometric variables including altitude that will allow for heating cost comparison.
Static air pressure as well as dynamic (velocity) air pressure within the AAHR system HVAC components can inhibit the blower airflow performance. HVAC duct material interior surfaces can cause friction of air molecules that affects the volume of heated air supply. Even rigid duct surfaces may look smooth, but have small imperfections and roughness causing airflow friction. Flexible ducts that have very visible ridges can create even more airflow friction. Airflow volume is constricted when the HVAC duct opening or orifice area, be it round, square, or rectangular, is not large enough to permit an optimum throughput of air. The amount of air delivered by the blower depends on the blower CFM airflow specification based on static pressure, which is important in any HVAC installation requiring detailed calculations of the airflow required to fit the supply duct dimensions. A constant flowing blower cannot move more air since the velocity is constant or at a fixed rate. The operation of an air handler moving the limited resource of heated air from the attic over a daily short time frame makes this a very sensitive issue when dealing with such static pressure and velocity pressure to overcome cost and efficiency challenges when gathering attic heated air, especially on cooler days. To address this problem, the present invention apparatus and methods advises use of short length rigid wall HVAC ducts with minimum duct turns to avoid airflow friction as much as possible for optimized operation.
An important technical problem associated with solar heat collectors is the difficulty in obtaining Btu measure to calculate energy cost savings without real time monitoring for measurement of temperature, relative humidity, and airflow volume. Solar heat collector economic savings is determined generally by measuring seasonal cost compared to the historical cost of a traditional heating method using rough calculations. A typical user cannot afford expensive data gathering equipment similar to the highly sophisticated data collection devices used by Minnesota State University study, for example; which made this point: “However, most buildings do not have a temperature sensor installed to measure the air temperature exiting their solar walls. This would be required (5 Tebbe et al., 2011, p. 4, para 3).” Present art apparatus and methodology should require some form of real time or incremental monitoring of heat, however, any monitoring method must be affordable for the ordinary consumer. Solar space heating Btu measurement results from temperature and humidity data logging becomes a good benefit to the consumer for purpose of making adjustments to manage operation of the space heating system in place.
There is a related technical problem with passive solar heating applications encouraged in modern architectural residential building design. Passive solar designs can be difficult to employ because building contractors often opt for construction of two story homes on smaller lot sizes making south facing glass marginally productive for passive exposure during the heating season due to building density. Many passive designs encourage roof slopes with windows placed in a high south facing position (in northern hemisphere), or skylights to gather wintertime sun in order to provide good passive solar heating; this is not easily done when remodeling a building structure. This problem limits the use of passive solar heating to being a very small contribution in energy savings for consumers.
Solution to the ProblemThe present invention referred to as the attic air heat reservoir system (‘AAHR system’) is designed to solve many of the technical problems discussed by providing simplicity of structure, use of readily available components, ease of installation, ease in enablement, and a method to measure energy savings. The present invention solution uses a comprehensive systematic approach including collecting data for calculations using a computer or by manual method in order to determine feasibility as well as to plan for appropriate configuration of the apparatus for installation by the user. A key to the solution and enablement is the use of “off the shelf” readily available HVAC parts, materials, air movers, electrical supplies and thermostatic devices coupled with the present invention's specialized attic/interior matching temperature controller for temperature management allowing for design and installation of a space heating appliance that is affordable. While solar energy optimization is most desirable, there is an undeniable concern of having a consistent supply of the basic resource, sunshine, that limits such optimization. The present invention enables the user to have the ability to maximize use of solar energy by providing a set of instructions within its methods for determining feasibility prior to purchase and installation of the AAHR system components. A systematic and comprehensive approach of the present invention involves understanding variations in the solar heat source using key mathematic formulas to select necessary apparatus and to facilitate efficient operation. Such key mathematical formulas provide guidance in dealing with operational issues, thereby enhancing user knowledge required for determining feasibility in use of the present invention.
The present invention methods include instructions for calculating Btu measure contained in an attic, based on its varying temperature and relative humidity levels. Calculation methods of the present invention help understanding of how to control and manage the AAHR system to optimize retention of the solar heat resource in the attic air for space heating. The apparatus and methods employed along with the simplicity of the AAHR system demonstrates effectiveness for space heating compared to that of more costly apparatus. The present invention is expected to perform at a level that is equal to or better than many of the existing solar heating applications presently available in commerce when measuring cost to performance while producing space heating savings for buildings, with attics and upper crawl spaces, located in suitable solar insolation zones.
Determining a geographic location's feasibility for a successful solar energy installation requires research of heating season solar insolation levels necessary for heat energy, specifically for space heating. Solar insolation maps illustrate solar ‘zones’ that are graded as to the solar insolation level measurement. Once a determination of good solar insolation is made, methods for establishing feasibility of the present invention as a comprehensive space heating system can be accomplished using the AAHR system methods of feasibility analysis prior to installation. Computer programmed formulas within the present invention methods determines desired solar heated attic air temperature on sampled days of the heating season in order to calculate the capacity required of a blower (air mover) to deliver adequate heat. The computer program calculates the level of sufficient airflow required of the blower/fan for most optimum drawdown of heat stored within the attic air heat reservoir. The computer program application of the present invention accounts for total Btu measure drawn through the AAHR system given optimum conditions that will contribute to increasing temperature within the interior air space while also accounting for heat that is absorbed into the building structure interior air, ceilings, walls and contents. An important aspect of the present invention methods is to provide computations that account for heat energy available from within the attic air heat reservoir throughout the daytime sunlight hours. Use of an inexpensive data logger to record temperature and relative humidity in the attic is required to make such computations. Utilizing the present invention analytical formulas enables the selection process for economic purchase of the AAHR system components, and facilitates on-going operation and management.
The attic air heat reservoir system (AAHR system) is a modality that emulates methods similar to apparatus of some present art by using an existing building structure's attic air space as a reservoir to store plentiful heated air for access in daytime during the heating season, with such heat generated by solar insolation normally available in many geographic solar zones. The AAHR system will be limited to locations where temperature measurements are consistently high enough in the attic for use as a building heating source. With sufficient quantity of heat stored in the attic air heat reservoir, there is an important benefit when attic heated air is supplied into the building interior to become also stored therein, for continued use of such heat during the nighttime. Heat storage within a building interior becomes most recognizable after sundown, when there is a gradual release of the retained heat residing within the interior materials. Release of heat from materials occurs through a fundamental of thermal energy called ‘diurnal temperature variation’. The ‘diurnal temperature variation’ results from conduction and convection of solar induced attic heat supplied into the building interior with such heat adhering to interior materials having been procured during sunlight hours by operation of the present invention. Such heat adhering in the materials releases into the interior air at night acting to slow normal heat loss from the building. The release of heat from materials during nighttime is an evidentiary contributor to the effectiveness of the present invention for space heating.
Heated air contained in the attic airspace is required to reside at a temperature greater than the building interior temperature desired by the occupants for effective space heating when employing the present invention. In this regard the American Society of Heating, Refrigeration, and Air-Conditioning Engineers (ASHRAE) published an ASHRAE STANDARD in 1995 (Addendum to Thermal Environmental Conditions for Human Occupancy, ANSI/ASHRAE 55-a 1995) which indicates the heating season's approximate temperature level for comfort of humans ranges from 19.4-24.4° C. (67-76° F.). The high temperature normally endured comfortably is about 23.3° C. (74° F.) at 60% relative humidity and 24.4° C. (76° F.) at 20% relative humidity as pronounced in the ASHRAE Standard. The comfortable temperature level range of 19.4-24.4° C. (67-76° F.) is for humans performing light primarily sedentary activity and wearing ordinary comfortable clothing. Comfort level range does increase slightly during cooling season as it allows for the body to adjust to heat through perspiration (24 American Society of Heating, Refrigeration, and Air-Conditioning Engineers [ASHRAE], 1995). During heating season, the temperature range to satisfy comfortable occupancy is important to the comprehensive methodology of the present invention (AAHR system). The present invention method is to allow solar heated air to raise interior temperature to such maximum comfort level (23.3-24.4° C.) (74-76° F.), depending on relative humidity, to stimulate more effective use of the short lived solar excursion of daytime sunlight hours so as to garner a maximum amount of heat energy for space heating cost savings. Additionally, the user can manage use of the attic-heated air by selective interior zone control to allow the heated air to accumulate in certain interior areas of the building for later dispersal throughout the interior by convection.
The AAHR system gathers and supplies the solar heated air through an independent and dedicated (closed loop) HVAC duct network or through an existing HVAC duct network for preheating or supplemental space heating. The present invention helps increase temperature inside the building even allowing for normal air exchange and typical heat loss. However, the effectiveness of the system depends on the severity of low outside temperature that can affect the building's attic air temperature required for suitable space heating. The AAHR system design allows for a variety of HVAC component installation options either small or robust in size to accomplish operation while the system, by its design, is also naturally scalable. Scalability of the AAHR system allows for unrestricted design options of the HVAC network and air handler(s) to enable sufficient airflow capacity as required, therefore addressing small to large building structures that have attics/upper crawl spaces suitable for the system application. Multi-story buildings of three or more stories may not have sufficient attic air space to serve all areas adequately using the AAHR system based on floor layout; however, solar heat would still be available for use to some measure. An example multi-story building situation is a top floor or penthouse having limited attic or upper crawl space that can still offer supplemental heating through building transfer passageways or HVAC ducts leading to lower levels. Multi-story buildings with acceptable roof design will use the AAHR system successfully in partnership with engineered heat recovery systems as well as with possible use of aforementioned TSAC solar collectors or other solar heat collector types mounted on the rooftop or an exterior wall.
The AAHR system HVAC related components are system operational devices (bimetal thermostats or digital thermostatic temperature control devices) to control its efficiency. The AAHR system makes use of solid-state temperature controllers to perform specific temperature measurement for the management of a single blower (air mover) or a plurality of blowers for space heating as necessary for environmental comfort inside a building structure.
Ordinary artificial heating HVAC systems cause interior air temperature to elevate when supplied by heating methods using direct flame, electric heating elements, or radiant heat (including steam heat) with most methods processing heated air through a heat exchanger. Current traditional HVAC technology uses expensive fuel sources to generate heat necessary to increase air temperature within the building structure. Supply and demand of such expensive fuels has required advances in existing and newer technologies to conserve their use. Conversely, the AAHR system utilizes the sun as its fuel source with the sun's energy having no direct cost associated with its heat content in the air, while such heated air is able to hold Btu measure for space heating. Btu content in heated attic air, created by the sun's energy, has an economic value placed thereon, using current market price of the heating fuel Btu measure replaced by such solar generated heat. Comparing the heat energy gathered for use by the AAHR system to that of a currently used fuel source determines the savings contribution of the present invention system that is accomplished with use of its apparatus and methods. Cost comparison between solar heated attic air, versus the artificial fuel source replaced when using the AAHR system apparatus and methods, demonstrates energy cost savings benefit for the user. Table 5 below illustrates data gathering of heat energy available in the attic to make such cost comparison.
Heated air in the attic or upper crawl space must be at a usable temperature for space heating when mixed with the colder interior air. The Btu measure in the heated air of the attic or upper crawl space of a building structure can be determined using the thermodynamic variable ‘enthalpy’. Enthalpy is the heat measurement expressed as Btu per pound of air taking into account the altitude, relative humidity, and temperature based on air density at the location. The science of thermodynamics associates with principles of psychrometrics relative to heat influencing water vapor and air as illustrated in a psychrometric chart. The psychrometric chart is a significant tool used by HVAC engineering professionals, studied for its methodology on the website ASHRAE.org and other HVAC industry related websites. The psychrometric chart provides data used to obtain Btu content within the air delivered by the HVAC system, of which enthalpy is the primary and most important variable to the present invention. The psychrometric chart display uses imperial units of measure ‘IP’ or international standard units of measure ‘SI’. The psychrometric chart comprises multiple mathematical formulas using thermodynamic principles relating to specific variables of: (1) dry bulb temperature, (2) relative humidity level, (3) enthalpy (Btu per pound of dry air), (4) water expressed in the measure “grains” included in air, (5) wet bulb temperature, (6) sensible heat ratio, (7) vapor pressure (inches of mercury), (8) dew point temperature, and (9) saturation temperature. A separate psychrometric chart must be prepared for each specific altitude (elevation) due to air pressure effect on such variables, with the base psychrometric chart normally computed for sea level. Computer programmed psychrometric charts are available that show results for altitude's effect on all the variables of the chart. Computer programmed psychrometric charts and psychrometric calculators are readily available on the internet for both novice users and HVAC professionals. The psychrometric chart provides a visual depiction of the variables of air molecules including vapor (moist air) illustrating all variable relationships with easy to understand plotted data. The psychrometric chart is a tool for quickly calculating any changes having an effect on the AAHR system performance during optimum daytime hours when solar energy supplies the required heat. Knowledge of psychrometric calculations using computer programs is an integral part of the methods of the present invention for an understanding of its space heating performance capability and energy cost savings for the user. Even though attic heat is measurable through use of the AAHR system, the system cannot however provide a steady Btu content, day to day, from solar generated heat because of the natural changes in climatic conditions occurring outside the building structure.
With knowledge of the psychrometric chart and its variables, the AAHR system heating performance is measurable for Btu content in the attic air supplied by the system. The most important thermodynamic variables discussed above are air temperature, relative humidity and altitude to arrive at enthalpy (Btu measure). Additionally, an estimate of efficiency of the HVAC duct system should be determined to consider friction (resistance) of airflow expected within the duct components. The AAHR system employs rigid wall HVAC ducts for efficient delivery of the heated air supply. With knowledge of the Btu/h/ft3 of air volume passing through the AAHR system at the blower capacity (CFM) and the HVAC network estimated percentage of efficiency, the total Btu/hr contribution to space heating can be measured.
The AAHR system employs specialized calculation methods to determine the airflow capacity of the blower/fan for use in the HVAC system operation, as shown in Table 6. Once the airflow capacity is determined, the required duct size can be accomplished using basic duct sizing charts for such purpose. Such calculations require some knowledge of static and velocity pressure in the HVAC ducts within a building that could affect overall performance of the AAHR system. An assumption estimate of 80% efficiency of system performance appears in Table 6. Table 6 calculations take a general approach in determining the AAHR system space heating capability. Table 6 formulas represent the methodology of selecting HVAC components for the AAHR system thus enabling planning by the prospective consumer. Table 6 formulas estimate performance and effectiveness of the apparatus size to be installed, and can provide an answer as to whether to go forward with an installation. An ordinary lay consumer can determine if a building site is suitable for the AAHR system application and methods through simple temperature and relative humidity data logging and use of Table 6 computations. The consumer must examine their own building design heat loss calculation prior to performing the computational process to determine the sizing of the HVAC air mover and component(s) required.
The present invention design, methods and installation can avoid technical problems when planning for multiple solar modalities by providing necessary information for integration with other such modalities already installed on a building rooftop. The AAHR system allows for utilization of a primary solar apparatus to be placed anywhere on the building rooftop or exterior wall even if the building is of minimal height. With the present invention located inside the attic, the studies previously mentioned would support reasonable performance from the AAHR system regardless of competition for the solar energy alighting on the rooftop during the heating season. Optionally, secondary solar energy apparatus can become independent of the primary building by placement on readily contiguous land or erected on outbuildings at the subject property.
The AAHR system accommodates regulating environmental conditions within a building structure suitable for human, plant and animal life, or for such building contents. Most building structures are ready candidates for the AAHR system that would include categories such as residential, commercial, industrial, agricultural, medical, schools, and government as examples, where the interior environment requires heating and ventilation during heating season suitable to conduct designated activities and tasks. The environmental conditions as managed in all these building structure types will include accommodation for the control of relative humidity, temperature, airflow, and the quality of air when using the AAHR system solar generated space heating modality.
Present art patents do not make the present invention less relevant when considering affordability and ease of use. Methods for selecting the AAHR system apparatus enables the consumer to use such methods to determine if the system can be a good investment rather than a poor investment prior to making a purchase decision. The economic advantage of a solar heating device is an important issue highlighted in Table 2 by illustrating the performance of several example present art devices in a comparative analysis. Table 2 demonstrates comparison of the present invention versus example products currently marketed to illustrate how well each device will perform during operation along with calculation of the projected economic payback to be expected. Table 2 includes various patented products and some non-patented products to illustrate such product application claims while tabulating the results of their performance and usefulness. The selected devices in this comparison also include apparatus that use attic heated air for space heating or for water heating. Table 2 demonstrates how investment cost versus solar heating performance of the referenced devices compare to the energy cost savings of the present invention. The devices selected by This Inventor represent a composite of marketed products drawing from a limited number of successful solar heating devices identified during research. In reviewing patent history of prior and present art in this category, it is apparent that such solar heating devices as researched follow along similar historical experience that befalls many patented apparatus by having limited success in commerce.
In summary, the present invention enablement features include specialized methodology that can easily incorporate into computerized digital devices, computer program applications (apps), and worksheet (spreadsheet) formulas, or can even be processed using manual math computation methods. Such methodology can instruct and facilitate the consumer in gathering of important and necessary data prior to implementation. The methods applied use the consumer's known and/or logged attic temperature data, for evaluation throughout the selection process to aid implementation of the present invention apparatus. Additionally, the present invention, as an attic based solar collector system for space heating, can be readily contained inside an existing building structure attic. This method for attic air space heat containment requires only reasonable incremental cost for the apparatus, including thermostatic controls, electric power wiring, air mover(s) and HVAC networking components, as described in the present invention, without the need for specialized or custom manufactured solar energy collector apparatus.
SUMMARY OF THE INVENTION Advantageous Effects of InventionAdvantages of the present invention (AAHR system) apparatus, its methods, disclosures and claims must first take into account the variability of solar performance for the given geographic location of the building structure. The Btu measure within solar heated attic air is not consistent day to day based on weather variations and location. Measuring of the AAHR system performance cannot be of an exact or finite manner compared to measuring performance of traditional heating appliances. The AAHR system utilizes the solar generated heat, when it is available, managing use of such heat with the thermostatic controls of the system causing shut down when temperature level in the attic is not suitable. Regardless of variation in solar energy available, the performance advantages of the AAHR system are apparent as enumerated point by point in the following paragraphs.
The AAHR system can overcome disadvantages of present art apparatus when accounting for space heating energy cost savings by using the attic air heat reservoir methodology. The present invention employs methods to help determine actual monetary value of the heating source in a novel and innovative approach that can easily aid in adaptation by consumers. To this end, the present invention makes use of components that are readily available through retail hardware outlets, jobbers, and distributors of HVAC equipment and supplies for purchase by the average consumer as well as professional installers and industrial users.
The present invention embodiments and methods provide for the selection of HVAC components and air handlers (blowers/fans) for optimum productivity to gather heated air from the attic, for space heating use. The AAHR system is not a discrete system of specialty configuration, and does not tether to custom manufactured components. Having flexibility in the selection of components overcomes issues that are evident with some current art devices that rely on inefficient plenum distribution systems or proprietary air movers and specialized thermostatic controls exclusive only to such devices. Installation of the present invention would be in any particular attic location for configuration using efficient and well-proven HVAC components.
The AAHR system is compatible with existing or future planned roof mounted solar systems. Solar infrared heat radiation can spread broadly over roofing material allowing for conduction and convection into the attic space even when existing solar systems are on the rooftop. As previously discussed, solar radiation can divert underneath a solar roof mounted apparatus where an air space resides between the apparatus and the rooftop, particularly in heating season when the sun's azimuth is lower on the horizon. Existing rooftop-mounted solar systems may include solar plastic piping or rubber bags used to heat water that will still permit conduction of heat into the roofing material during heating season.
With attic air vents sealed or partially sealed, the attic air heat reservoir has sufficient air exchange to provide a ready supply of air for heat processing by conduction and convection when coupled with air circulation caused by the blower as it sucks in the heated air for supply to the interior. Building codes in the United States generally require ventilating standards expressed as net free vent area based on the square feet of attic floor area. Net free area of attic air vents is the vent open space, thus excluding materials that obstruct airflow such as vanes and any supporting structure. However, a case study by Shimin Wang and Zhigang Shen suggests that attic ventilation should be a design option instead of a universal requirement to reduce heat load. Such case study appears as a research report “Effects of Roof Pitch on Air Flow and Heating Load of Sealed and Vented Attics for Gable-Roof Residential Building” also disclosing influences that can reduce building heating load by sealing the attic (25 Wang and Shen, 2009). Further consideration for the method of the present invention requiring sealing of attic air vents, appears in an important principle within thermodynamics called “coefficient of convection”, a contributing factor to the success of the AAHR system when the blower causes circulation of heated air contained in the attic. Convection of heat can increase with a modest increase in airflow caused turbulence that amplifies heat transfer to the attic air from the attic peak area during the blower intake process. Normally the attic air exchange involves ambient air of lower temperature moving through structural ventilation openings (vents) by normal outside forces with such exchange occurring up to four (4) times per hour depending on vent configuration. Air exchange would be much lower when air vents are partially covered which is recommended for the present invention (assuming the AAHR system is quiet), but this is overtaken when the system becomes operational. An example air exchange results with a 400 CFM blower operating for 60 minutes that can suck 24,000 cubic feet of air through the AAHR system located in a 6,000 cubic feet attic (about 2,000 sq. ft of floor area gabled attic), thereby experiencing four (4) air exchanges. The AAHR system will emulate an attic ventilator by causing a higher multiple of air exchanges during operation while drawing air from the roof structural openings such as chimneys, plumbing or septic vent openings, waste heated air escaping from the building interior, and any partially opened attic air vents. Such operation increases the air exchange to provide the necessary air supply required for the space heating operation, while also contributing to the coefficient of convection.
The AAHR system space heating performance benefits from a building's diurnal heat variation with the incident of thermal mass residing in such building's materials contained in the working or living interior. Diurnal temperature variation is a thermodynamic process where heat from the sun is absorbed into the building's interior materials (historically considered a passive solar occurrence) by effect of thermal mass. Thermal mass is a material's capacity to absorb heat depending on its molecular structure or mass. The diurnal temperature variation occurs usually over a single 24-hour day when heat is gathering inside such materials in daytime until the sun recedes with heat released back into the interior air from such materials during the nighttime. Passive solar applications and architectural designs to capture the sun's rays for its heat as it enters a building through glass windows is well known for the diurnal temperature variation. The diurnal temperature variation works well in warm climates and not so well in cold climates. Martin Holladay, a contributor to Green Building Advisors in his article entitled, “All About Thermal Mass—Interior thermal mass can sometimes help lower energy costs—but in cold climates, it's won't help much”, has included this statement by Mr. Alex Wilson as follows: “In northern climates, when the temperature during a 24-hour period in winter is always well below the indoor temperature, the mass effect offers almost no benefit, and the mass-enhanced R-value is nearly identical to the steady-state R-value.” (26 Holladay, 2013). The AAHR system on the other hand, can overcome this problem in colder climates when heated air in the attic from solar insolation resides at a temperature above the indoor temperature thus becoming useful for space heating. The AAHR system effectively moves the sun's “passive heat” energy into the building interior with such heat subsequently being absorbed into the interior materials through action by the present invention as though collected in a “passive” manner through a window, therefore able to take advantage of the diurnal heat variation even in a colder climate.
The AAHR system can take advantage of any heat energy from attic air appropriately high enough in temperature for space heating that otherwise would be wasted, even if the attic temperature were not warm enough or acceptable for human comfort. The heated attic air can still benefit a building that is unoccupied, albeit the temperature may be lower than the normal minimum for human comfort. Controlling use of any available heat in a colder attic can be of benefit using the following scenario of an unoccupied building: (a) An unoccupied building interior temperature has dropped below 10.0° C. (50° F.) while the AAHR system attic temperature controller is set to turn on at 10.0° C. (50° F.), with the building's existing heating system turned off. (b) Assume the sun is shining and the outside temperature is cold with the AAHR system interior thermostat set higher than 10.0° C. (50° F.) or as dictated by the user. (c) With the attic temperature controller set to turn on at a temperature of 10.0° C. (50° F.) the AAHR system will begin operation to supply heated air sufficient to preheat the building with air that is warmer than 10.0° C. (50° F.) prior to resumption of normal activity, thereby preventing the building interior temperature from falling even further. This above scenario illustrates flexibility with the AAHR system to utilize any available attic heat that is useful for contributing energy cost savings with less artificial heat being necessary.
The AAHR system being robust and scalable makes collaboration possible with mechanical HVAC devices such as heat exchangers or heat pump systems for extracting additional heat from the attic air heat reservoir for other duty such as heating domestic water. Additionally, the use of solar collectors, including transpired perforated type (TSAC) or similar apparatus, can augment or enhance the AAHR system when employing such solar heat collector mounted on a south facing wall during heating season in North America for example, to enhance space heating thus being able to use the two different modalities in partnership.
Action by the AAHR system attic temperature controller ensures continuous use of available heat when made ready by the solar insolation affecting the attic air space. If solar insolation were intermittent due to weather, the attic temperature controller would stop and restart periodically as the attic temperature moves above or below the desired operating temperature setting. An ordinary bimetal thermostat or digital temperature controller for managing the interior temperature level desired by the user, set at a maximum for comfort of 24.4° C. (76° F.), will optimize use of the attic-heated air when temperature dictates. The AAHR system introduces a third specialized attic/interior matching temperature controller, an integral element of the present invention, to ensure use of all available Btu measure by allowing collection of useful heat energy as long as both the attic temperature controller status and the interior temperature controller (or bimetal thermostat) status are both on. This specialized attic/interior matching temperature controller ensures that the attic will supply as much heated air to the building interior when temperature in the attic exceeds the interior temperature, or until either the attic temperature controller or the interior temperature controller have stopped to shut down the AAHR system operation.
A unique and beneficial phenomenon of the AAHR system is demonstrated by the blower/fan causing air movement within the attic (attic airspace is sealed with vents closed or partially closed) making it possible for attic air to be continuously ‘wetted’ from substantial heat when such air comes in contact with the attic ceiling (peak area). Convection at the attic ceiling peak occurs as the attic air molecules meet with the heated attic ceiling materials when heat has conducted through the roof. Convection spreads heat throughout the attic air from the steady air movement of the blower while such blower is in operation. Such convection wetting process is a very beneficial aspect of the AAHR system operation within the sealed attic as both ambient air and waste heat air converge to the attic ceiling, enhanced by circulation of the system blower.
It is not enough just to develop a solar apparatus such as the AAHR system for space heating need, it must be of general economic benefit, in particular as to use of fossil fuels. Natural gas as a heating fuel produces about half the amount of carbon dioxide per Btu generated versus the worst offender, coal. However, realize there are still carbon dioxide emissions occurring when natural gas generates the electricity used for space heating as well. Using the AAHR system as a supplement to ordinary fossil fuel heating systems or its derivatives such as electrically produced heat is further justification for its use, regardless of how much heated air is available for space heating through the AAHR system.
Supply of attic-heated air from the AAHR system to the interior using thermostatic temperature control enables a steady and continuous stream of such heated air throughout the sunlight hours. Attic temperature increases substantially when solar heat is available usually over several hours, allowing consumption of the heat energy available from within the attic to occur in a continuous manner by such thermostatic control. The AAHR system temperature controllers, setup in series, manage supply of heated attic air to increase and maintain an interior temperature level that avoids any discomfort to occupants or animals. Adhering to a thermostatic temperature setting that allows air temperature within the building interior to rise substantially will enable maximizing the Btu measure for later release into the interior as any residual heat adhering to interior's material surfaces is released during the aforementioned diurnal temperature variation effect occurring at nighttime. This release of heat through diurnal temperature variation thereby reduces use of traditional heating fuels from a gas furnace or other heating appliance, made possible by allowing the AAHR system to operate continuously to heat the interior air above that considered a normal interior temperature settings during the sunlight hours, perhaps as high as 24.4° C. (76° F.). Meanwhile, replenishment of heat in the attic by the conduction effect of solar radiation permeating the building roof material and other surfaces continues even while the blower draws the heated air through the AAHR system for use. Further, the remote sensor of the attic temperature controller placed within the attic/crawl space transmits real time temperature readings to help avoid supplying cooler air that is not conducive for the building interior heating needs. The heated air supply from the attic may be controlled (a) through use of a building interior thermostat to avoid overheating, or (b) by regulating the upper limit temperature setting of the attic temperature controller to stop the AAHR system, or (c) by a method using the attic/interior matching temperature controller of the AAHR system for sensing the attic supplied air temperature that has dropped below the present interior temperature level in late afternoon.
Commonly used measure of heat energy as applied to HVAC systems are methods of the present invention to quantify the Btu measure available in the attic air. The Btu measure can be reasonably determined from variables of temperature, relative humidity and altitude (air pressure effect) to compute the enthalpy variable value (heat energy as Btu per pound of air). Enthalpy is the resultant thermodynamic variable that determines Btu of moist air measured in cubic feet flowing through the AAHR system; the enthalpy value is divided by the specific volume of air (the cubic feet of air volume in a pound of air) to determine the Btu content in such volume of air. Altitude affects the value of the specific volume of air due to air pressure change. The AAHR system methodology for determining Btu/h/ft3 measure in the air during operation is obtained by recording the temperature and relative humidity with a specialized data logger in 30 minute intervals posted to its storage memory (30 minute intervals is preferred for reasonable accuracy). Download of resulting data periodically, or at the end of the heating season, provides for processing through the present invention's computer spreadsheet application. Such computer application calculates the total Btu measure residing in the attic air during the AAHR system hours of operation, which results in total heat energy value as Btu measure used for space heating. The computer application uses the air mover CFM rating to determine heated air volume gathered during daily operation, for calculating the grand total of Btu collected in such air volume based on selected start and stop thermostatic temperature settings for the AAHR system operation. The computer worksheet application so devised for the present invention facilitates counting total Btu measure supplied during the AAHR system operation, including the ability to calculate the total Btu for any period of days, or weeks, or for the entire heating season.
The AAHR system also operates with use of a fan associated with cooling electronic computer equipment, with rotational speed upwards of 3,400 rpm, in a 6″ or 7″ form diameter, to move a large volume of air within a small HVAC duct of 6″ or 8″ diameter. Such computer fan replaces the traditional blower/air handler of the HVAC duct. Such fan is very low cost, while able to cope with humidity, condensation, and temperature extremes like traditional HVAC apparatus. Computer fans use ball bearing axles for long operating life, using minimal electricity consumption. Computer fans can also be of a type to operate on direct current low voltage delivering 300 CFM using 54 watts on 12Vdc which is ideally suited for remote locations and applications where solar PV panels may be installed and available to produce low voltage electricity of direct current type (DC) in closed loop systems. Even a building without electric power could accommodate this type fan powered by battery recharged with a PV powered electric battery charger. Computer fans using alternating current 120Vac can also deliver 300 CFM on only 27 watts at rotational speed of 3,200 rpm. Sound levels are higher in the computer type fans necessitating installation of a duct muffler incorporated in the HVAC supply duct for noise reduction, depending on the fan's location.
The AAHR system performs competitively to that of present art devices currently marketed, when being compared in an analysis involving several examples of solar energy apparatus for space heating including attic based solar heating devices. Using a stratification analysis, the AAHR system is compared to related art space heating apparatus and their methods as discussed in the “FIELD OF THE INVENTION” section for their respective affordability and performance characteristics shown in Table 2. Mention has been made of solar energy devices other than those used for solar water heating and photovoltaic electricity generation experiencing low adoption rate in commerce due to high implementation cost compared to a traditional heating apparatus. The AAHR system intends to break down the cost barrier for consumers since the present invention can offer a minimally configured apparatus by using readily available components for installation at affordable cost while also offering good heating performance. The comparative value stratification analysis illustrated in Table 2 demonstrates investment payback expected of the various example solar heating systems currently offered in the consumer marketplace versus the AAHR system. Table 2 comparison of present art devices assumes all devices would be operating at 2,500 feet altitude to make a fair comparison using the published specifications and data available from each of the respective manufacturers at an average heating season's daytime temperature and humidity. Choosing the 2,500 elevation is a midpoint between sea level and 5,000 feet altitude to arrive at a general value for enthalpy. The performance of each present art device uses assumptions of a constant temperature and relative humidity level to provide a fair and balanced analysis. Cost effectiveness of the present invention for use in commerce measures up to be in good standing compared to the other devices as described therein.
The AAHR system performance for energy cost savings experienced by This Inventor resulted from data gathered from the system installed at the test property during heating season 2014/15 operation. A valuation method making use of Heating Degree Days (HDD) during the heating season can help with comparison of energy costs when using traditional heating methods. Using HDD method of cost comparison, a value of $0.30 per HDD has been placed on each HDD “Heating Degree Day” which is a selected example fuel cost of $1.20 per therm for natural gas using the historical HDD heating seasons experienced at the test property prior to the 2014/15 heating season. Such HDD rate of $0.30 is from historical heating bills at the test property taking into account about 30-45 days during each heating season when the property is vacant. A 3,000 HDD heating season would cost $900 in natural gas consumed while a 2,000 HDD heating season cost would be $600 for natural gas consumed at $0.30 per HDD (using the $1.20 per therm in both these cases). The present invention can furnish upwards of 40% of space heating required in a colder heating season and 50% of space heating required in a warmer heating season at the test property location. An example 3,000 HDD at 40% savings would be 1,200 equivalent HDD for the heating value furnished by the present invention, or $360 in savings. An example 2,000 HDD at 50% savings would be 1,000 equivalent HDD for the heating value furnished by the present invention, or $300 savings. However, the monitored results at the test building site using the AAHR system during the 2014/15 heating season (October 2014 through April 2015), based on weather data of 2,168 HDD, resulted in 53.3 M/Btu potentially usable for space heating by the attic air heat reservoir using criteria as shown in Table 5 part 3. This result was substantially more than expected. The 53.3 M/Btu (533 therms in natural gas terms) determined by the present invention formula, could not all be used for space heating as explained from deductions made as follows: (1) 2.6 M/Btu for days of excessive heat requiring the system to be manually turned off; (2) 5.3 M/Btu estimated at 10% of the attic heat caused by either exfiltration (waste heat) from the interior, some heat loss in the attic to its colder regions, or other unaccountable inefficiencies partly due to increasing the interior temperature setting as about 3.9° C. (7° F.) above the 18.3° C. (65° F.) base temperature; (3) 10.5 M/Btu for days when the property was vacant 47 days of the 2014/15 heating season. Therefore, there was a net 34.9 M/Btu or 349 therms utilized from operation of the AAHR system for space heating at the test property during the 2014/15 heating season. The AAHR system as tested has a duct muffler on one HVAC duct line causing some duct loss from static and velocity pressure in the system as evident from the monitoring shown in Table 7 below; therefore net heat entering the interior would be similar to the efficiency of a traditional modern furnace at about 80% efficiency. The 349 therms available from the operation of the AAHR system are valued at $524 using the actual current natural gas rate of $1.50 per therm in the 2014/15 heating season. This calculation of $524 in savings highlights the comparison of Btu measure (or natural gas therms equivalent) between attic produced heat and natural gas instead, when making use of attic heat from the AAHR system. Such comparison takes into account that billing of natural gas is gross usage from meter measurement before consumption by the test building's furnace, further affected by the furnace operating efficiency factor of about 65 to 75% for older furnaces and 80 to 90% for newer furnaces. The furnace in the test building is 35 years old with efficiency of approximately 65 to 70%. This compares to the efficiency of about 80% for supplied attic heated air passing through the AAHR system HVAC ducts. One important issue is that interior temperature in the test building design heat loss calculations uses 18.3° C. (65° F.) balance temperature. The normal interior temperature setting in the test residence is 22.2° C. (72° F.), as established for heating the interior, is above the design heat loss at 18.3° C. (65° F.) balance temperature causing excessive use of the heat above the normal heat loss expectation. In addition, other temperature management issues occurred on warmer days during the heating season that contributed to some waste of attic heat in addition to normal heat loss by adjustments made to the temperature controller settings during experimentation. Table 5 part 3 is actual attic heat logged data for the 2014/15 heating season October 2014, through April 2015. The total natural gas billing rate in the 2014/15 heating season increased to approximately $0.39 per HDD, a $0.09 increase over the previous year's natural gas rate. This increase results from 30% natural gas rate hike ($1.15/therm average in the 2013/14 heating season increased to $1.50/therm in the 2014/15 heating season—a 30% increase); this would have resulted in a natural gas bill for ‘heating only’ of $846 for the 2,168 HDD space heating need. The actual natural gas billings for heating use only during the 2014/15 heating season was $291 (at $1.50/therm average) resulting in a net savings in heating costs of $555 ($846−$291=$555) when using $0.39 per HDD to cover the 2,168 HDD at the property. Using the cost at $0.39 per HDD shows such $555 net savings comparing very close to the $524 calculated savings for the 349 therms used per the Table 5 part 3 data at the current natural gas rate of $1.50 per therm. Additionally, the present invention attic/interior matching temperature controller, not used during the 2014/15 heating season, would have avoided manual shutdown of the AAHR system as mentioned above. The above data indicates a successful operation of the present invention. However, the computed heat available in the attic was much more than expected due to unusually warm temperatures and drought conditions besetting California throughout the 2014/15 heating season, having had 2,168 HDD compared to the prior six (6) heating season's average of 2,878 HDD. Considering the above results, energy cost savings will vary for a user due to significant spread of cost between types of heating fuels such as electricity and natural gas as the heating fuel source. To illustrate such cost spread, the following is a calculation from estimated U.S. nationwide average heating fuel costs, based on assumption of 300 therms gathered from attic-heated air, while employing the AAHR system, with such 300 therms replacing the two types of artificial heating fuels mentioned to demonstrate cost savings during a heating season:
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- (1) Natural gas price is $1.20 per one (1) therm (at 100,000 Btu rounded).
- (2) Electricity is $0.12 per kilowatt with one (1) kilowatt equal to 3,412.14 Btu. Therefore, 100,000 Btu is equivalent to 29.3 kilowatts costing $3.51 per therm ($0.12 times 29.3 kilowatts=$3.51 per therm).
- (3) Assume the AAHR system provides 30,000,000 Btu (300 therms) total for the heating season.
- (4) The value saved if using electricity as the source for heating is $1,055 (300 therms×$3.51)
- (5) The value saved if using natural gas is $360 (300 therms×$1.20).
The present invention air mover (blower/fan) may be of a type that produces a constant volume of airflow without regard to altitude correction, although air pressure changes can affect results due to certain air friction known to HVAC science as static pressure and velocity pressure, while duct volume capacity is also a factor. Airflow volume affected by static and velocity pressures within an HVAC system results in reduction of the cubic feet volume of air flowing during and after such air passes through the blower. The constant volume of air so delivered contains less mass as altitude increases thereby affecting the Btu measure of heat available, while an increase or decrease of relative humidity in the air also affects the Btu measure depending on such altitude. The constant volume airflow describes the blower output CFM specifications as selected for optimum performance, and for adequate supply of heated air to the building structure interior. The air mover (blower) operates with sufficient airflow output by installation of a scalable HVAC network with very few limitations. The blower optimum airflow must be suitable at a given altitude accounting for changes in weather and available solar insolation to affect the quantity of adequately heated air being available for space heating throughout the heating season. Alternatively, certain manufactured blowers operate at different velocity levels by using a variable speed control activated with an independent remote digital controller; this method however would be subject to constraints of HVAC duct diameter causing velocity and air pressure changes involved thereto that can affect overall performance for space heating. Additionally, use of HVAC rigid duct components enable the AAHR system to maximize efficiency in supplying the attic-heated air for space heating regardless of the air mover capacity.
The following tables describe methods necessary for establishing feasibility and selection of apparatus required to perfect the use of the present invention, while demonstrating its advantageous operating effects.
Table 2 describes solar energy performance for several example patented and non-patented devices currently marketed in commerce comparing such apparatus cost to its energy savings performance for gathering solar heat Btu measure. Such savings performance for each apparatus, based on published specifications of each manufacturer, compares the present invention savings performance to the example related devices. The devices incorporated in this table are those from the related art discussed previously. The devices referenced as column numbers 1 through 7 are compared to the present invention (column labeled number 8) for their heat gathering performance using equal internal temperature of 26.6° C. (80° F.) at relative humidity of 30% for a location at 2,500 feet altitude. Such temperature of 26.6° C. (80° F.) of heated air available inside the inner workings of each device is for the entire heating season as might be expected from solar insolation at a moderate elevation permuted to the referenced device specifications heat output during space heating operation. Table 2 illustrates economic investment payback for each device compared with that of the present invention. The dollar value in energy cost savings is based on the performance of the device, as measured for heat output, valued at a present day natural gas rate ($1.20 per therm being a national average in 2014/15 heating season). Table 2 is an analytic presentation format to support any research made by a prospective consumer for further study and to help determine feasibility of the present invention apparatus for purchase and installation. The data in Table 2 is a best effort compilation of the technical specifications and source data offered by each referenced device's manufacturer cited in their literature in addition to assumptions made for any unknown conditions due to a lack of specific data; such assumptions being necessary to equitably compare such device to the others. Table 2 uses the measured airflow output as specified by the manufacturer of each device at its expected internal and output temperature based on typical conditions similar to that at the test location to complete the comparison. Table 2 compares the present invention performance to that of the aforementioned referenced devices showing the Btu measure per cubic feet of heated air available for space heating as produced by each device. The Btu measure as derived from said published and tested specifications for each referenced device provides the basis for the dollar value of Btu measure produced by each device which is priced by using the national average natural gas heating cost. Estimated hours of operation throughout a typical heating season as used in this comparison are 763 hours for fixed vertical devices and 900 hours for attic-based devices. The 763 hours used for fixed vertical devices comes from the Solar-Infra Systems (item label 1) device. Solar-Infra Systems estimated 5.8 million Btu over 9 months at 7,600 Btu/hr (using a 72 CFM flow rate indicated by the company) from the 8 sq. ft. collector panel. The 763 hours is a fair representation due to difficulty of discerning this value in other devices (80 CFM flow rate is included in Table 2 based on recent sales literature of the Solar-Infra Systems product). The 900 hours of operation for attic heating devices comes from the operating hours of the AAHR system at the test building during the 2013/14 heating season, which is near historic normal. Table 2 stratifies the economic cost and the related energy cost savings of the devices. Table 2 also makes comparison of costs based on the retail acquisition price known for each device. For example, included in the installation cost comparison is a cost factor of $25 per sq. ft. of collector area selected for the SolarWall® TSAC product. The $25 is a representative value determined to be the average of a retrofit cost at $30 per sq. ft. and a new installation cost at $20 per sq. ft., from the referenced citation in the Journal Of Solar Radiation Energy report (Sewalk et al., 2013). It is important to note that as a ‘Do It Yourself’ project (DIY), the investment payback can result in substantial energy cost savings and shorter investment payback time for the consumer for each of the comparison products by eliminating outside labor charges. Table 2 discloses maximum Btu/h for each of the devices compared, without regard to efficiency of the heated air delivery system involving HVAC ducts or otherwise. For example, when using a window-mounted device with the fan blowing, the heated air goes directly into the building interior without going through an HVAC duct system.
Table 3 demonstrates the attic air heat reservoir Btu measured capacity for nine examples of attic air space volume (2,000 cu. ft. to 8,500 cu. ft.) at various attic temperature levels expected. Table 3 values are the heat energy calculations (in Btu measure) that can aid in determining blower (air mover) airflow output required to satisfy the interior cubic feet requiring space heating. Outside temperature of the air, wind conditions, and solar insolation supplied by the sun, will affect increases in temperature while also causing changes to relative humidity within the attic air resulting in a change of Btu measure; Table 3 is but one example using 40% relative humidity for illustration. The Table 3 calculation of Btu measured heat in an attic, at selected temperatures encountered, uses a constant 40% relative humidity at a specified altitude location of 3,500 feet enumerated with example volumes of attic air space measured in cubic feet. The table illustrates the heat content available when the attic air has reached a minimum temperature of 18.3° C. (65° F.) that would be sufficient for transport through the AAHR system to the building interior. Table 3 includes the results of calculations using mathematical formulation for the psychrometric variable ‘enthalpy’ to yield the Btu measure per cubic feet of air within the attic space shown. The table values are for enablement of the prospective consumer in determining a blower airflow specification that would provide adequate volume of heated air for their application. Attic air exchange, depending on construction and ventilation methods, will benefit from continuous convection of air heated by solar heat energy conducting through the building roof as it reaches the attic air space. The AAHR system blower influences such air exchange as it draws the heated air for supply to the building interior. Using a 400 CFM blower in an attic of 5,000 cubic feet would result in air exchange of 4.8 times, and using a 300 CFM blower in an attic of 5,000 would be 3.6 times air exchange assuming attic air vents are closed. If air temperature average is 23.9° C. (75° F.) with a 3.6 times exchange, 31,475 Btu/h could be gathered from the 5,000 cu. ft. attic throughout the operational period of the day as the sun continues to heat the exchanged air. Temperature and relative humidity logging of data performed inside the attic is an important task for accurately determining heat level generated by the sun. The most accurate analysis method for determining how much heat is being retained in the attic necessitates withdrawing heated air during the logging process using a blower/fan rated with a CFM airflow likely suitable for the application. Validation of the Btu measure retained in the attic occurs with use of the temperature and relative humidity logging device for data download into the computer worksheet application of the present invention shown in Table 6. The temperature and relative humidity logging device as installed inside the attic, remains there over several weeks to provide data for analysis. Data logging example at the test building is illustrated and further described in Table 5 Parts 1, 2, and 3. This logged analysis would provide reasonable assurance that sufficient heated air can be available over a specified number of sunlight hours of operation by the AAHR system as a heating source for the building structure.
Table 4 is the design heat loss calculation for the test building (a 1760 sq. ft. single-family residence) as required for energy consumption and furnace sizing necessary to obtain a building permit prior to construction. Building design heat loss calculations determine the required furnace Btu/h output to heat the building during a worst case lowest outside temperature of the heating season. The calculation illustrates the ability to determine the AAHR system effectiveness in comparison to the design heat loss of the particular building for its intended purpose. This design heat loss data is integral to the calculations made in Table 4. The test building latitude and longitude along with its altitude shown in Table 4 substantiates the following data. The test building geographic region experiences heating degree days in a range of 2,450 HDD to 3,400 HDD during heating seasons over the recent past 5 years of history (2013/14 and prior) which demonstrates the varying weather conditions being encountered in the area. The 2014/15 heating season for the location was particularly warm being outside the range referenced above resulting in 2,168 HDD October 2014 through April 2015. Table 4 design heat loss is a certified calculation of the professional engineer's estimated annual heating season natural gas consumption of 58.6 million Btu in a normal 2,500 heating degree season for the test building. The 58.6 million Btu would translate to $879 annual cost at $1.50 per therm of natural gas or $703 at $1.20 per therm for the 2,500 HDD. Annual Btu consumption calculation of 58.6 million Btu results from a total 44,913 Btu/h based on maximum temperature variance of 7.8° C. (46° F.) at 2,500 HDD over a 24 hours period. This calculation for the 7.8° C. (46° F.) maximum temperature variance is (44,913×24×2,500÷46° F.=58,582,173 Btu in total). Table 4, is also a computational format recommended to a prospective user who would enter their own data to determine Btu measure required during heating season that can be partially satisfied with heated attic air using the AAHR system. Design heat loss is calculated using the heat resistance data factors (R-value) of the building structure envelope assemblies which is to be determined for all elements of the structure including the foundation, or slab perimeter that meets directly with the outside temperature. Heat resistance factors (R-value) are used to calculate the building's design heat loss in order to estimate its hourly Btu consumption measured as heat loss ‘per degree’ from the entire building which is determined from the heating season coldest outdoor temperature expected. The design heat loss data as shown in Table 4 is important to the present invention application methods by using psychrometric variables to determine the approximate blower/fan CFM rated airflow volume necessary for optimal use of the AAHR system further described for use in Table 6. A key element to the AAHR system installation is to determine the design heat loss encountered during various weather conditions while the AAHR system is in operation. The calculations for determining heat loss from a building envelope is based on outside temperature (TO) compared to the inside temperature (TI) being less than 18.3° C. (65° F.) Fahrenheit which is typically the standard “balance” temperature for most building structures located in moderate climates; the temperature difference is referred to as Delta T (TI−TO) in Table 6. A building is considered in balance when the inside temperature residing at 18.3° C. (65° F.) is equal to that of the outside temperature also residing at 18.3° C. (65° F.) which presumes that no heat loss will occur from the building interior based on typical construction standards for buildings (balance temperature can differ in various geographic regions and for specific types of buildings). The heat loss calculations for a building include integral data used in mathematical formulation methods for the present invention. Table 4 example illustrates 976 Btu/h design heat loss for each one (1) degree increase of interior temperature in the entire air volume of the building living space with such heat required to overcome the exterior cold temperature effect on the building structure to maintain the interior temperature at 18.3° C. (65° F.) in the heating season. This metric of Btu/h per degree for design heat loss of the building is an integral part of the method of the present invention for calculations in Table 6 below.
Table 5 is a computer program worksheet application that performs calculations of Btu measure obtained from digital data logger readings of temperature and relative humidity levels at the test-building site. Three parts make up Table 5, each part using the same-logged database from the test property 2014/15 heating season. The computer program uses known psychrometric formulas to determine enthalpy (heat in Btu per pound of air) measured against the known cubic feet per pound of air (at a given altitude) to arrive at Btu per cubic foot volume of heated air available in the attic air space as averaged from two successive 30 minute intervals of data logging. The altitude of the location is very important for the calculation due to air pressure at the particular elevation having an effect on the result. The temperature and relative humidity data is necessary to provide valuable and substantive information regarding the building's attic heat reservoir to contribute sufficiently heated air for space heating. A stream of logged temperature and relative humidity in intervals of 30 minutes provides data for the computer program. The computer program application is performed using parameters of: (1) the building location's altitude, (2) the starting temperature desired, (3) the stopping temperature desired, (4) the cubic feet per minute of blower airflow output, and (5) the selected date range of temperature and humidity recordings required for accumulation of the Btu measure to be calculated. The computer program processes the logged data to calculate the average value of Btu measure obtained from two successive 30-minute intervals, by applying the CFM rate of the blower during operation against the data obtained during a selected range of dates. The computer program accumulates total Btu measure supplied by the blower using such selected parameters and the dates desired, printing the report as shown in Table 5. Table 5 consists of three worksheets: Table 5 part 1 is data logged during Oct. 29, 2014 through Nov. 15, 2014. Table 5 Part 2 is data collected on Nov. 4, 2014 at the test building to show the actual 30-minute interval temperature and relative humidity levels recorded by the data logger from morning to evening. Table 5 Part 2 shows the calculation of Btu measure available within the attic at the selected blower CFM airflow for the starting temperature and stopping temperature user criteria selected. Table 5 Part 3 is a summary total of the 2014/15 (October through April) heating season data of temperature and relative humidity showing total Btu measure generated for each calendar month. The data shown for each calendar month of the heating season is: (1) the average of the high temperature recorded for all days, (2) the average temperature encountered in the attic during the actual hours of use for all days, (3) the Btu daily average for the hours of use for all days, (4) the total Btu measure generated that month, and (5) the average hours of operational use by the AAHR system for each month. Historical outside weather temperature data was collected from weather station KCAHESPE8, located within one (1) mile of the test building made available on the Weather Underground website dashboard weather station historical data referred to as the “Almanac” (28 Weather Underground, 2015). At the time all the temperature and humidity logging was being performed, during the heating season, the AAHR system was operational and sucking attic heated air for supply into the building determined by the criteria start to stop temperature settings. With the AAHR system operational, the process of rebuilding heat in the attic, while heated air is gathering through the blower at the rate of 400 CFM in the test-building attic, demonstrates how robust the heat transfer and convection activity is within the attic creating usable heat from solar insolation during sunlight hours.
Table 6 Part 1 is a worksheet of mathematical formulas to determine the blower (air mover) CFM output required to supply sufficient heated air volume, in cubic feet, into the interior of the test building structure, using the AAHR system. The data processed in the formulas is reconciled with the building design heat loss calculations made by a professional engineer (P.E.) prior to issue of the building permit as described in Table 4. The AAHR system heating performance is associated with the psychrometric variable ‘enthalpy’ (Btu measure per pound of air) requiring calculation of the blower airflow output from manufacturer's specifications. Table 6 formulations calculate the blower (air mover) volume output necessary to satisfy the interior volume of air space. Such calculations require data to include attic-heated air at certain temperature level, relative humidity and the altitude location as psychrometric variables to be input in data fields (marked as → in the table). Table 6 calculation formulas are integral to the present invention, but such formulas are foreign to normal HVAC calculation standards primarily because of the instability of the weather, the building site, and the thermal mass of building materials contained therein. Additionally, thermal mass of building materials (See Table 6 Part 2) is very important when considering how much heat energy is captured then retained based on thermal mass of the materials inside the building that can enhance the attic heat reservoir's space heating effect. Thus, the AAHR system makes use of the building interior as a supplemental heat reservoir for overall efficient operation. The thermal mass of interior building materials is generally ignored in engineering design heat loss formulas because the primary focus is on the building envelope where the bulk of heat loss occurs. Moreover, engineered calculations of building design heat loss do not account for variations in relative humidity and altitude when making such calculation. Table 6 worksheet therefore illustrates Btu measure flowing from the primary heat source attic air heat reservoir, for absorption by the building's interior materials, with such materials able to retain the heat energy in the form of the aforementioned thermal mass. Formulas in Table 6 worksheet ascertain the temperature increase within the building interior required for space heating needs based on calculated airflow. Table 6 Part 2 is the supplemental data researched from comprehensive sources for calculating specific heat on a per square foot basis of the interior materials which is more easily understood and measurable than using volume of such materials. With such specific heat calculation, Btu measure includes heat absorption of the building contents, as well as the interior airspace of the building interior during the heating season, which is an integral part of the worksheet calculation in Table 6 Part 1.
Comments for Table 6 Part 1 and Part 2:
1. Table 6 uses building design heat loss data plus interior material and contents estimates of specific heat
2. Building envelope area of the ceiling and exterior walls are included in ITEM G
3. Interior ceiling sq. ft. of materials (wood, gypsum, laminate, etc.) retains heat beyond envelope heat loss
4. ITEM P temperature heat gain from normal 68° F. to estimated high expected to be 75° F. (example=7° F.)
5. Enthalpy calculations from Psychrometric Calculator (27 The Sugar Engineers, 2015)
6. Temperature and relative humidity logged in attic to ascertain ITEM K and ITEM L for an example month
7. ITEM AE concrete specific heat Btu/sf/degree is set at 50% of value expected due to absorption time lag
8. ITEM AF Floors (NOT INCLUDED) is not applicable to test building (Test building has Slab on Grade)
Table 7 is data from attic heated air supplied into the test building interior by the AAHR system with such air supply being affected by temperature level, static air pressure, and dynamic (velocity) air pressure. The manually recorded data is from 2013/14 heating season observations of temperatures within the attic as the heated air is transported into the test building interior through two air supply diffusers, one diffuser located in the main indoor hallway leading to the bedrooms and the other diffuser located in the family room. The temperature variations between the attic temperature and the AAHR system supply temperature illustrates a reduction of Btu measure as temperature increases with a relative humidity decrease at peak daytime hours of operation while operating the AAHR system. The results also illustrate what happens when air molecules expand as the air increases in temperature from the resulting air pressure to cause airflow restriction in the duct supply system causing a perceptible drop in supply temperature relative to the attic intake temperature. This data also demonstrates Btu measure of heated air as it becomes drier and less dense during the later hours of operation resulting in a drawdown of humidity from the attic-heated air. The attic heated air humidity level becomes lower following such drawdown of the volume of warm moist air held in the attic in the earlier hours of the day's operation using the AAHR system, because overnight conditions normally result in increased relative humidity that will remain into the early morning sunlight hours. Results of AAHR system operation shown in Column P demonstrates a reduction of 10% to 15% airflow efficiency at the family (Fmly) room diffuser outlet, which is being supplied through a 20 ft. long 6″ in diameter HVAC duct incorporating a duct muffler to reduce blower noise. Such duct muffler measures 18″ long by 6″ inside diameter and 10″ outside diameter containing 2 inches thick commercial grade sound absorption foam formed inside the 6″ diameter tunnel through which air flows in the body of the muffler. It should be noted that the temperature readings in Table 7, at the outlet diffuser, are affected somewhat by the heated attic air mixing with the interior air near the diffuser; this has an effect on the actual temperature recorded by the manual readings as the temperature sensor is located about 8″ below the diffuser. Use of an infrared laser thermometer showed temperature of the metal parts of the diffuser to be near that of the attic air temperature, attributed to thermal conduction effect of temperature holding onto the galvanized metal duct. Also after 2:00 pm in the afternoon, at the highest attic temperature usually experienced, the relative humidity level will have dropped, thus resulting in lower Btu level per cubic feet in the air supplied, regardless.
Table 8 is an abbreviated schedule of measured solar insolation monitored in most USA regions during 4 years of study, illustrating example cities arranged in order of most to least amount of such solar insolation available, including some regions having marginal results for comparison (30 Solar Energy Applications Laboratory, 1978). This same data type is also readily available from the aforementioned NASA website, with various other websites having links to NASA or similar solar insolation sources. The table highlights many differences in solar radiation (insolation) by geographic area. Data in this table discloses Ely Nev., a city in a high mountainous region having significant ‘heating degree days’ (HDD) but also having strong solar insolation at the location. This data is very important to the present invention methods being necessary for research by the consumer when determining feasibility and potential for the user space heating application.
Table 9 illustrates coloration and composition of certain roofing materials measured for solar performance to demonstrate effects of such materials to attract or repel solar insolation. The source data shows the comparative insolation values of selected roofing materials. Table 9 also includes results of a study performed by Florida State Energy Center that compares solar reflectance of roofing materials based on material type, paint type and coloration. Table 9 highlights color as well as type of material with a grading system that would enable the user of a solar space heating system, such as the present invention, to determine whether the roofing material can sustain necessary solar radiation for conduction into the attic area. Regardless of the disclosed performance characteristics of such roofing materials, considered to be beneficial or not for the present invention operation, the aforementioned temperature and relative humidity logging as described in Table 5 above is encouraged as the best method for determining feasibility of the AAHR system.
Summarizing the advantageous effects of the present invention, the primary elements of utility, enablement, and industrial applicability include these main points: (1) Attic air vents closed to better retain daytime heat capture. (2) Efficient control of available attic temperature for space heating using selected thermostatic control devices with remote temperature sensing. (3) Employment of standard “off the shelf” HVAC components for robust and scalable application. (4) Use of computer assisted calculations to determine the present invention suitability for its intended use. (5) Logging of temperature and humidity in methods for determining space heating savings (6) Use of specialized attic/interior matching temperature controller to optimize gathering heated air from the attic. (7) Engaging the diurnal temperature variation as an advantage of the thermal mass effect of interior materials that adds to space heating efficiency of the present invention.
For an understanding of this disclosure and its operation, reference is made to the following descriptions of the accompanying drawings in which:
In the following, the parts of the invention are referenced by numerals applicable to
- 1 attic air heat reservoir system (AAHR system)
- 2 building attic peak area
- 3A attic area air ventilation grille opening(s)
- 3B attic air ventilation grille cover(s)
- 4 air filter material installed over air intake boot
- 5 air intake boot
- 6 intake duct components (rigid type straight duct, tees, elbows, and wyes as required)
- 7 blower/fan unit (air handler)
- 7A optional blower/fan unit (variable speed control type)
- 8 HVAC supply duct components (rigid type straight duct, tees, elbows, and wyes as required)
- 9 diffuser, vent register (with mounting box)
- 10 wiring to blower from thermostatic control devices
- 11 remote temperature sensor probe located in attic space leading to controller 12
- 12 attic temperature controller (set to cooling only mode)
- 12M temperature controller programmable memory
- 12P temperature controller solid-state processor
- 13 thermostat wiring to temperature sensor in attic space from temperature controller 12
- 14 interior temperature controller, programmable thermostat or standard line voltage bimetal thermostat
- 14M temperature controller programmable memory
- 14P temperature controller solid-state processor
- 15 temperature controller remote temperature sensor for interior use
- 16 attic/interior matching temperature controller (polls temperatures of attic versus interior)
- 16M temperature controller programmable memory
- 16P temperature controller solid-state processor
- 17 remote temperature sensor probe located near diffuser with lead wire to controller 16
- 18 wiring for joining attic temperature controller to a line voltage interior bimetal thermostat(s), or to an interior temperature controller that uses a remote sensor
- 19 fuse to protect digital temperature controller in event of main power amperage spikes main power source to the AAHR system (120Vac, 220Vac, 12Vdc or other) within sub-panel optional duct muffler
In the following, the parts of the invention are referenced by numerals in accordance with the list applicable to
- 1 temperature controller electric power port (hot) 120Vac 10 A example
- 2 temperature controller electric power port (neutral)
- 3 temperature controller electric power port (hot) in association with 1
- 4A temperature controller electric power port (hot—when relay is energized) to interior thermostat
- 4B temperature controller electric power port (hot—when relay is energized) from interior thermostat to blower
- 5/6 temperature controller ports for remote temperature sensor
- 5A/6A two lead wires for communicating sensor signal to temperature controller
- 7 temperature controller chassis rear port area
- 8 temperature controller chassis console (panel) with operating buttons and display screen.
- 9 interior thermostat (line voltage type) using bimetal temperature sensing apparatus
- 10 blower/fan (air mover)
- 11 NTC (Negative Temperature Coefficient) temperature sensor probe located in attic
- 12 main power source circuit breaker
- 13 electricity (hot)
- 14 electricity (neutral)
- 15 ground (earth)
- 16 sub panel to contain wiring connections for AAHR system operation
- 17 fuse to protect temperature controller when amperage rating dictates
In the following, the parts of the invention are referenced by numerals in accordance with the list applicable to
- 1a attic temperature controller electric power port (hot)
- 2a attic temperature controller electric power port (neutral)
- 3a attic temperature controller electric power port (hot)
- 4a attic temperature controller electric power port (hot—when relay is energized)
- 5a/6a attic temperature controller ports for remote temperature sensor
- 1b interior temperature controller electric power port (hot)
- 2b interior temperature controller electric power port (neutral)
- 3b interior temperature controller electric power port (hot)
- 4b interior temperature controller electric power port (hot—when relay is energized)
- 5b/6b interior temperature controller nodes (ports) for remote temperature sensor
- 1c attic/interior matching temperature controller electric power port (hot)
- 2c attic/interior matching temperature controller electric power port (neutral)
- 3c attic/interior matching temperature controller electric power port (hot)
- 4c attic/interior matching temperature controller electric power port (hot—when relay is energized)
- 5c/6c attic/interior matching temperature controller (ports) for remote temperature sensor used to read interior temperature
- 7c/8c attic/interior matching temperature controller (ports) for remote temperature sensor located in attic duct or at supply diffuser for attic air temperature read
- 9 attic temperature controller terminal ports (rear)
- 10 interior temperature controller terminal ports (rear) [may be substituted with interior thermostat (line voltage type) using bimetallic temperature reading apparatus]
- 11 attic/interior matching temperature controller terminal ports (rear)
- 12 main power source circuit breaker and/or sub panel with circuit breaker/fuse
- 13 electricity (Hot)
- 14 electricity (Neutral)
- 15 ground (earth)
- 16 NTC temperature probe located in attic for communicating with ports 5a/6a
- 17 NTC temperature probe located in interior communicating with attic/interior matching temperature controller ports 5c/6c
- 18 NTC temperature probe located in attic communicating with attic/interior matching temperature controller ports 7c/8c
- 19 NTC temperature probe located in interior communicating with interior temperature controller ports 5b/6b
- 20 heated air supply diffuser exiting at ceiling blower/fan (air mover)
Notes regarding descriptors on the numbering above:
-
- A. The term “port” is synonymous with terms of: wire connection, terminal, or node; as a point at which a wire makes solid connection for electrical input and output.
- B. Lead wires for communicating temperature sensor signal to the temperature controller terminal ‘ports’ relating to
FIG. 4 are: sensor 16=5a/6a, sensor 17=5c/6c, sensor 18=7c/8c and sensor 19=5b/6b. - C. The temperature controllers 10, 11, and 12 console front panel with operating buttons and display screen is not displayed in
FIG. 4 .
There are other aspects and features of the disclosure that will become more apparent upon reading the following detailed description in conjunction with the accompanying drawings. The AAHR system and methods can be availed upon with modifications and alternative constructions not limited to those detailed below, therefore the intention is to cover all modifications and alternative constructions or any similar configurations falling within the spirit and scope of the present disclosure. Referring now to the drawings, the AAHR system and related HVAC component descriptions and methods are illustrated in the Figures to include drawings as shown.
The AAHR system primary thermostatic control begins with temperature changing components 12 and 14 in communication with the indoor blower 7. Electric wiring 10 communicates hot electric power to blower 7 governed by action of the temperature changing components that include attic temperature controller 12 and interior temperature controller 14, both containing internal electric powered relay switches that are in a ‘normally off’ status. A bimetal thermostat may substitute for controller 14. Attic temperature controller 12 communicates through electric wiring 13 with attic remote temperature sensor 11. Attic temperature controller 12 operates in series with interior temperature controller (or bimetal thermostat) 14 operating in partnership to manage blower 7 to an on or off state by reacting to the temperature of attic air and the temperature of interior air. Remote temperature sensor 11, located in the attic, transmits the attic temperature value in real time in communicating with the attic temperature controller 12. A starting (turn-on) temperature parameter value, when encountered in real time, will cause the attic temperature controller 12 to activate its onboard relay switch in communication with the interior temperature controller 14 that must be in a “power on” status to begin powering blower 7 to supply heated attic air for space heating. The attic temperature controller 12 operates in “cooling mode” in the manner of an electrically operated ventilator to demand suction of available heated air from the attic air heat reservoir by communicating power to blower 7 as controller 12 reacts to increased temperature during sunlight hours. The heated attic air moves by blower 7 at a temperature above the minimum parameter set point temperature recognized by attic temperature controller 12 when attic air is suitable for space heating. Weather variability or intermittent cloud conditions that cause temperature changes would result in occasional stops and restarts of blower 7. Such intermittent conditions and subsequent fluctuations in temperature of the attic air heat reservoir may be a normal occurrence on days experiencing marginal solar radiation or fluctuating outside temperature to cause attic temperature to waver near the programmed setting of attic temperature controller 12. Solar radiation during sunlight hours promotes heat conduction and convection to increase temperature in the attic-heated airspace to become the source of natural heating fuel of the present invention. Waste heat from the building interior can also rise into the attic by natural upward momentum as it exfiltrates to mix with the attic air before being drawn into air filter 4 for transport through blower 7. Electricity powered wires 18 connect the attic temperature controller 12 to the interior bimetal thermostat or temperature controller 14 in series mode. Thermostatic controllers operate in series mode, whereas if only one thermostatic unit reaches its programmed temperature setting to an ‘off’ state, the operation of the AAHR system will shut down. Therefore, each thermostatic unit 12 and 14 must be active in an ‘on’ status simultaneously for the system to be operational.
Although, an HVAC plenum enables a plurality of supply ducts to communicate with the outlet side of blower 7, the AAHR system performs best without such plenum. Use of a plenum can result in airflow friction and air pressure with a degrading (negative) effect on the AAHR system performance. The preferred method for an efficient airflow is to incorporate a single short length of rigid HVAC intake duct components 6 while employing a minimum of the HVAC supply duct components 8 leading to the ceiling or wall mounted diffuser 9 located centrally in the building structure. The short length rigid HVAC duct network is most efficient when joined with HVAC supply duct components 8 that include a plurality of wyes or tees leading to a plurality of diffusers 9 when necessary. The intake duct 6 fluidly communicates with the inlet side of the blower 7. The HVAC supply duct components 8 extend from blower 7 communicating with the building interior diffuser 9. Diffuser 9 allows heated air supply to exit through its orifice control mechanism (vent register) used to regulate the volume of air supplied to the building interior. The preferred positioning of diffuser 9, comprised of a movable vent (vent register with control lever), is in a fully open status during the sunlight hours of use throughout the heating season. Diffuser 9, vent register may be closed if cold air is incoming, if the building is not in use, or if the attic area temperature remains at a level below that suitable for space heating for some period. Emphasis is on use of a short HVAC network of supply duct components 8 to avoid air friction on the cornered surfaces of HVAC components such as elbows and tees, or flexible duct having multiple ridges. It is important to recognize air molecules have mass and although invisible to the eye can slow down during transit when the mass of such molecules move against HVAC component surfaces that essentially bump against each other causing turbulence, thus causing inefficient airflow. Additionally, the actual surface features of many HVAC metals or plastics can result in more friction thus reducing efficient delivery of the heated attic air so supplied.
The AAHR system 1 control management mechanisms starting with attic digital temperature controller 12 physically located in the building interior for convenience of the user to make settings for operation. The attic temperature controller 12 relies on electronic input transmitted by the remote temperature sensor 11 located inside the attic area. The attic temperature controller 12 contains a solid-state electronic memory 12M supporting an onboard processor 12P capable of storing and controlling temperature parameters including hysteresis (differential temperature), start temperature and stop temperature. Additional parameters contained in memory 12M are entered in controller 12 console to include settings for lower limit temperature, upper limit temperature, and starting delay time in minutes. Interior temperature controller 14, comprised of either an interior bimetal thermostat or a temperature controller of the same type as attic temperature controller 12 set for “heating mode” communicates operatively in series with interior temperature controller 14 to maintain precise control of the attic heat transported by blower 7 to the building interior. The interior thermostat of a bimetal type 14 (with its own onboard temperature sensor) or an interior temperature controller 14 communicating with temperature sensor 15 allows the user to set a desired temperature for a particular building interior zone associated therewith. Digital interior temperature controller 14 communicates with temperature sensor 15 for temperature reading at an interior wall location to manage a specific interior zone, or for managing the entire building interior heated air supply. The interior zone may require a plurality of blowers or multiple HVAC components 8 such as tees and wyes to divert the airflow through a vane(s) to become an element within HVAC supply duct network 8 for the specific application with such vane(s) either manually or electronically controlled. The AAHR system is limited to use in the heating season, although optional use would be possible during cooling season by reversing flow of blower 7 for removal of heated air from the building interior. During cooling season, removal of heated air from the building interior to the attic area through ‘opened’ attic air ventilation grilles occurs by reversing airflow with physical rotation of the blower mounted on a rotatable table (for seasonal directional change), or by electrical motor reversal method if such motor has this capability. Such heated air removal would normally occur at nighttime, with HVAC A/C off, or may be toggled in daytime using low differential degree setting without sacrificing HVAC cooling.
Integration of an optional variable speed motor within the AAHR system configuration, involves a motor of a preferred model with a manufactured variable actuating controller operatively coupled to optional blower 7A. Use of a programmable temperature control apparatus would be required to operate such variable speed motor. The user enters a desired temperature and airflow parameter into a variant of thermostat 14, with data transmitted to a variant of system temperature controller 12 recognizing the user selected criteria for communicating with such temperature controller 12 to manage status of alternate blower 7A to an ‘on’ or ‘off’ state accordingly. The attic temperature controller 12 would communicate a control signal to the optional blower 7A via the programmable control apparatus peculiar to the variable speed motor at a desired rated rotational speed (rpm) to produce the required level of airflow volume. A desired motor speed rating for blower 7A should be of sufficient volume airflow that may be associated with a specific operating parameter, such as the differential temperature setting established to control the desired room temperature or under unusual conditions such as interior area doors opening and closing. Motor control devices include those that respond to airflow rate and motor speed to communicate with a computer memory of a digital control device based on standard airflow specifications of such motors; such motor control device operates in association with the turbine type blowers manufactured to interface with such motor control device.
An alternative duct muffler 21, within the HVAC supply duct components 8 of the AAHR system configuration, suppresses high velocity noise of a 12Vdc computer type fan, or otherwise to accommodate for occupant noise discomfort.
A pertinent item not shown in
An alternate type of electricity source can power the AAHR system installation configuration illustrated in
To conclude, the foregoing description represents elements that comprise the AAHR system operating as a solar energy space-heating device that emulates a typical HVAC system using common HVAC components. The teachings and disclosures used in conjunction with other types of HVAC systems known to those of ordinary skill in the art generally provide understanding of the methods employed for controlling the heating of a building. However, the AAHR system heating efficiency requires knowledge of environmental conditions that include solar insolation levels, outside temperature fluctuation, wind chill, relative humidity, and altitude location of the property, therefore those familiar with HVAC systems require added skill and understanding of solar energy principles in the undertaking.
Full disclosure of a product in the marketplace for patent effectiveness of the embodiments of the equipment and methods employed are tantamount to the entire set of claims and embodiments of the device. The specific disclosures herein will be apparent to those skilled in the art that allows for modifications and variations made with components and methods without departing from the scope of the disclosure.
Claims
1. Apparatus and methods for acquiring heated air from within the under roof enclosed attic airspace (or upper crawl space) of a building structure to include controlling the operation of a blower (also described as a fan, or air mover) selected for its effective output to supply such heated air contained therein for space heating. Such apparatus and methods identified as an ‘attic air heat reservoir’ system (AAHR system or present invention) is for use principally during the heating season in geographic locations having adequate solar energy. The present invention utilizes such blower(s) to transport heated attic air through a preferred closed loop network of HVAC components and supply duct terminating at a diffuser leading into a building structure interior space comprising:
- A building attic air space generally sealed from outside ambient air with attic air ventilation openings mostly closed to become a reservoir for the solar heated air thus preventing heated air from communicating with a large volume of colder ambient air through the attic air vents generally placed in the roof or the attic exterior walls. Such attic air ventilation openings being mostly covered ensures adequate heat retention within the attic air space thus allowing air temperature to rise substantially in the attic peak area, which promotes increase of Btu measure for optimum space heating performance;
- Furnace air filter(s), commonly designed for HVAC use, placed at the heated air intake for filtrating attic air to an acceptable quality prior to entering the present invention HVAC ducts for the intended space heating purpose;
- A plurality of thermostatic control devices communicating with remotely located temperature sensors to transmit real time reading of temperature within the attic as well as temperature reading within the building interior. Such thermostatic devices regulate the flow of heated attic air under management of user-controlled parameters programmed therein to maintain a desirable interior space temperature level. Remote temperature sensors communicate temperature signals to solid-state digital temperature programmable control devices set with parameters for start/stop temperatures and hysteresis (differential temperature) to manage the building interior environment suitable for humans, animals, equipment, agricultural enterprise, etc.;
- Economical and scalable HVAC network components including blower(s)/fan(s) [air mover(s)] selected to supply attic-heated air at a normally predetermined constant volume airflow. Such blower airflow volume, expressed in cubic feet per minute (CFM), is published in specifications and literature by the manufacturer to enable the user to select an appropriate blower unit. The blower regardless of the location's altitude typically moves at a constant volume during operation, with such airflow transported through an HVAC duct of suitable volume dimension for capacity to supply the heated air. The HVAC blower(s) selected is capable of supplying the heated attic air in volume sufficient for space heating during sunlight hours of the day, throughout the heating season when solar generated heat is available. Such HVAC components and air movers are readily available “off the shelf” in commonly scalable sizes up to and including industrial size air movers and components;
- Methods to include computer programs using formulas incorporated within a plurality of stepped analytical applications to determine the amount of solar heat energy available in the attic air obtained through temperature and relative humidity data logging. Such methods including computational programmed spreadsheets that can specify the required apparatus configuration of the present invention for space heating. The computer program methods provide data to determine economic accountability of energy savings when such energy is measured using thermodynamic formulas designed for analyzing space heating performance of the present invention apparatus;
- Such configuration of the apparatus, computer programmed devices, and methods operate within the comprehensive system of the present invention for enablement and maximum utilization of the sun's available heat energy to raise temperature in attic air during sunlight hours for purpose of space heating with solar energy becoming the heating fuel source, which is claimed.
2. A method to incorporate a particular component for solar energy used in space heating identified as thermal mass of structural elements within the interior building assemblies and contents. Specific heat capacity measured from thermal mass is included in a reconciliation of total heat supplied from the attic air heat reservoir, during its daily operation, as accounted for in the measured heat provided through space heating of the present invention. Accounting for total heat load within the building interior is important for optimum use of attic-heated air. Heat load (design heat loss) of a building is based on the building envelope assemblies that meet the outside air, ignoring interior assemblies and related elements such as interior wall surfaces and all interior components including décor (furniture, etc.), fixtures, interior walls and cabinets. Such interior assemblies and related elements have the ability to retain heat beyond that normally considered as heat load, but HVAC principled computations made for ‘design heat loss’ ignore thermal mass of interior assemblies. This thermal mass phenomenon manifests in the diurnal temperature effect made possible when the interior materials retain such heat. Although thermal mass for building interior elements is difficult to quantify accurately, because of enormous variance in their mass, nevertheless, such heat retention value can be determined from known data regarding thermal mass of building materials and other substances available from a wide range of sources in the fields of architecture and building science. The non-envelope interior assemblies and materials become heat storage elements during daytime operation of the present invention as it supplies the attic-heated air into the building interior. The present invention methods include calculations using specific heat capacity per square foot of area, translated into the mass volume of the building interior assemblies and contents, using values from reference sources showing specific heat value that can be stored in such material mass volume. This transfer of heat emulates a passive solar heating process when sunlight enters a window as solar radiation beams directly onto interior surfaces such as floors and walls. Btu measure as retained in the building interior materials becomes a supplemental heat reservoir for use by the present invention to offset normal heat loss through the building envelope. Such supplement heat contributes to increasing or maintaining interior air temperature when accounted for in the diurnal temperature variation, which is an important factor for efficient use of the heated attic air, for space heating, which is claimed.
3. Methods employing mathematical formulas to optimize the collection of attic heated air determined by assessing the volume of airflow through the blower, measured in cubic feet per minute (CFM), as necessary for space heating. Such methods are atypical in normal HVAC heating system sizing. The methods for employing such mathematical formulas of the present invention is facilitated through use of thermodynamic principles to determine available heat energy in the attic air at the given altitude location of the building structure. The present invention methods determine the HVAC network for best system performance by employing mathematical formulas by computer program calculations or by manual calculations. The mathematical formulas include the thermodynamic variable ‘enthalpy’, to determine Btu measure of heated air flowing through the present invention apparatus as it supplies heat to the building interior. Such formulas calculate the present invention HVAC network character to perform best within a range of attic air space temperature and humidity levels through establishment of airflow volume required of the blower (air mover) for optimum gathering of the heat energy available within the attic air. The mathematical formulas use data obtained from interval measurement logging of temperature and relative humidity levels within attic air during sunlight hours of operation to determine the Btu total of available heat energy. The present invention methods includes heat loss calculations for the given building structure, for input into such mathematical formulas. Heat absorption properties (thermal mass) of interior building materials is also integral to the mathematical modeling formulas based on the specific heat calculation of such materials. Data elements from the actual building design heat loss are also necessary in the mathematical formulas for such modeling. The mathematical modeling provides a reconciliation of heat load of the building to balance with sufficient Btu measure supplied by the present invention apparatus. The formulas determine the potential output of Btu measure of attic-heated air moving through the blower to balance with interior air volume along with heat energy stored as specific heat in each material type in a reconciliation of the total Btu required for operation during a typical day of moderate outside temperature. The formulas also include provision to require an estimate of any moderate temperature gain in the building interior as planned for by the user during the daily solar heat excursion. The calculation formulas make up a comprehensive mathematical modeling vehicle performing specific steps for the elements of discovery. The calculation formulas includes the recognition of Btu measure of the specific heat absorbed by all types of materials within the building interior which are subsequently affected by the diurnal temperature variation. The present invention apparatus operation can contribute to sufficient temperature rise within the building interior to reach levels that meet guidelines for human comfort going as high as 24.5° C. (76° F.) with relative humidity level scaling from as high as 60% down to 20%, which is tolerable for humans, animals and plants. Allowing such temperature rise to occur inside the building helps promote increasing the effect of thermal mass, which contributes to diurnal temperature variation to the benefit of the overall space heating process. Such methods of utilizing mathematical formula applications are designed to model the present invention space heating contribution to benefit the prospective user to include necessary information from known and estimated variables, including specific heat capacity of materials, blower output, and expected energy cost savings within their building prior to installation which is claimed.
4. A method employing computer programmed instructions integrated into a specialized attic/interior matching temperature controller to sense temperature of the building structure in two locations: (1) supply outlet diffuser (or attic supply duct near the diffuser), and (2) building interior living or working area, to manage the distribution of heat retained in the attic to avoid conflict of the two atmospheres' temperatures. The specialized attic/interior matching temperature controller periodically polls temperature to manage the building environment by area or zone to ensure optimum supply of heat from within the attic air heat reservoir. A temperature sensor polls attic heated air temperature as such heated air exits through the HVAC supply duct diffuser, to enable the temperature controller operatively to prohibit colder air of the attic from entering the interior when such interior air temperature (also polled by the controller using a separate temperature sensor) is higher than the attic air temperature at the end of the daily solar cycle. Determining when attic air temperature is lower than interior air temperature is required to avoid supplying the interior with colder air from the attic than that of the current interior temperature of the building. This specialized temperature controller requires minimal user intervention. The specialized attic/interior matching temperature controller permits use of the maximum amount of heat energy within the attic during the daytime operation without forcing the air in the interior to lose heat at the end of the daily operating cycle of the present invention, which is claimed.
5. A method as to claim 1 utilizing attic air space as a reservoir of heat, rather than employing a costly manufactured solar heat collector apparatus comprising specialized material or unique design form necessary to retain such solar heated air. Solar generated heat energy contained within the attic air space generally has favorable temperature excursion from early morning into the early afternoon peak when sunlight contributes adequate heat energy as it rises to maximum temperature level then lowers as the sun recedes on the horizon. Such heat captured within the attic air space, which is the attic air heat reservoir, is subject to a daily time limit during which sufficient Btu measure becomes available for space heating when location, sunlight hours and weather conditions dictate. Hours of sunlight are uncertain due to variable weather patterns that can affect the buildup of necessarily sufficient heat from solar energy for absorption into a building's roofing materials and the surrounding attic structural materials. Such uncertainty and limited hours of sunlight make it necessary to operate the present invention in an effective manner to draw as much heat energy as possible from said attic air heat reservoir for space heating. The attic air heat is isolated therefore undisturbed from influences such as wind or rain. The circulation of attic air within a sealed attic space, by suction of the blower, causes a positive physical effect of fresh ambient air and waste heat to come in contact with the heated attic ceiling as suction of the blower accelerates heat transfer to induce convection coefficient of heat energy throughout the attic air. The attic air heat reservoir therefore relies on multiple thermodynamic features for efficient capture of heat energy contained therein for space heating, which is claimed.
6. A method as to claim 1 employing a digital temperature controller set for “cooling mode” to communicate with a remote temperature sensor strategically located in the attic. The controller functions in a manner similar to an attic air ventilator, with attic-heated air transported into the building interior rather than ventilated outside the attic. The attic temperature controller stores temperature parameters to start and stop the blower operation, as established by the user, when attic air is warm enough for space heating. The attic temperature controller is a device comprising (a) a digital processor; (b) a memory operatively coupled to the processor; and (c) a remote temperature sensor. The attic temperature controller contains an electric wire coil relay switch, typically a normally open SPST type (single pole, single throw), activated by the digital temperature controller's processor responding to the parameter settings programmed into the device. A more robust relay switch is necessary when operating blowers of higher energy load. The temperature controller features a wide range for its hysteresis adjustment to compensate for cooler HVAC components in the morning enabling the blower to start at a higher temperature than the stopping temperature. The attic temperature controller set to “cooling mode” feature is ideally suited to manage the present invention for space heating while the attic temperature rises and falls during sunlight hours, which is claimed.
7. A method as to claim 1 for determining attic air temperature using a negative temperature coefficient (NTC) sensor or thermistor strategically located in the attic to enable real time communication with a digital temperature controller containing multiple variable parameter settings for the efficient operation of the present invention. With solar energy being the unique heating fuel source, the excursion of temperature within the volume of heated air, so contained in the attic space as temperature increases then lowers, offers usable heat energy for an unknown period during sunlight hours. Such remote temperature sensor in communication with the temperature controller enables placement of such temperature controller console inside the building for convenience of user thermostatic management decisions. Remote location sensing of temperature coupled with differential temperature parameter setting thereby allows the attic temperature controller to manage operation with precision, which is claimed.
8. A method as to claim 1 whereby the present invention temperature controllers manage operation with minimal user attention during an entire heating season. The thermostatic control starts when attic temperature is high enough and stops when attic temperature can no longer be useful during sunlight hours. Changes to attic thermostatic control start and stop temperature settings, throughout the course of heating season weather pattern shifts, necessitate strategy change for optimum use of the heat energy that is available within the attic air heat reservoir as well as thermal mass of interior materials. Daily operation, during absence of occupants, can prevent the building interior from cool-down. The present invention apparatus supplies heated attic air into the building interior even while occupants are away from the premises, daily or intermittently, enabling pre-heating of the interior environment when the existing traditional heating appliance is off, to ensure optimum use of available attic heat, which is claimed.
9. A method as to claim 1 of the present invention comprising versatile, robust and scalable apparatus employing commonly produced HVAC components that are affordable for the user to benefit from a respectable economic payback for their investment outlay. The present invention apparatus components are readily available as “off the shelf” in the marketplace to include common and easily understandable parts and materials for those who may desire to perform a “do it yourself (DIY)” home or business installation. Professional solar device installers, HVAC jobbers and electricians would prefer the versatility and scalability features. Such professionals are normally conversant in the present art technology with an advantage of ease in implementing present invention apparatus for their customer needs. The simplicity of the system offers potential for wide adoption where solar heating energy is practical. The versatility and affordability of the present invention shows by example using an ordinary electric timer, or even just a simple electric switch, to turn on or turn off the air supply blower, instead of using digital thermostatic devices, which may further reduce installation expense. Respectable economic payback is a benefit through the present invention novel approach in configuring components of lower cost than that suggested for most present art devices. Versatility, affordability and scalability is known in the selecting of HVAC components within the present invention, while also offering flexibility to allow for modification or enhancement of space heating apparatus, which is claimed.
10. A method as to claim 1 to reduce inherent static pressure and velocity pressure within the present invention HVAC network of components in favor of a simplified rigid duct configuration for gathering the available, but limited, heated attic air efficiently. The attic air heat reservoir has a limited time in which heat is available throughout the sunlight hours of operation. Air friction inside the air handling equipment is a critical element for efficient movement of such limited available heated air. The present invention use of low friction rigid ducts with very few duct turns reduces static pressure and velocity pressure that would cause air mover and HVAC network inefficiency. Reducing static and velocity pressure in the HVAC duct network thereby enables conserving as much heat as possible during peak hours when solar energy heating reaches its maximum level, which is claimed.
11. A method as to claim 1 to optimize containment of heated air in the attic air space whereby a majority of attic air ventilation openings are covered by shutters, panels or other suitable materials to enable solar generated heat to substantially increase attic air temperature during the hours of sunlight. Blocking the attic ventilation openings reduces outside colder ambient air from exchange within the attic air space. However, air exchange will accelerate during operation in sunlight hours when sufficient heat is available and contained to the advantage of the present invention as the blower sucks in such heated air. Therefore, when covering the ventilation opening at the perimeter of, or at the ceiling of the attic structure, the air temperature resists cooling by ambient air of a lower temperature entering through any open attic air vents. Covering air ventilation openings would also avoid any wind accelerating the cooling effect upon such cooler air entering the attic air space. The preferred method of closing attic air vents for containment of heat and humidity enables the present invention to perform adequately as a space-heating appliance during heating season, which is claimed.
12. A method as to claim 1 for employment of the attic air space under the roof structure of common architectural design and suitable roofing materials that absorb heat. Such roof structure becomes an ad hoc solar heat collector protected from outside weather conditions. Although roofing materials enable absorption of solar insolation at varying efficiencies, such materials nonetheless become a receptacle for solar heat with such heat conducted into the attic ceiling and throughout the structural elements of the voluminous attic without requiring partitioning or any major building structural changes. Roof slopes in normally colder climates are very steep and attics more voluminous, but such attics can retain necessary heat near the attic peak area. The present invention draws heated air from near the attic ceiling peak to benefit from the attic area of warmest temperature and optimum Btu measure during the sunlight hours of the day. Typical roofing materials facilitate good solar absorption and heat transfer. A preponderance of material types presently used on building structures such as asphalt shingles, concrete tile, and a number of other well-qualified roofing material types facilitate heat conduction and convection inside the attic air space; therefore, such attic air space ideally functions as the reservoir for heated air, which is claimed.
13. A method as to claim 1 to make use of relative humidity normally resident in the attic air during the nighttime, such humidity is subject to weather conditions and changing dew point during heating season. The present invention draws warm humid air contained within the attic space during its daily sunlight operation with such warm humid air having increased level of Btu measure for supply to the building interior as the day begins. The relative humidity level within the attic space gradually falls during sunlight operating hours as humidified air moves to the drier and colder interior of the building structure during action of the present invention. Removing humidity from the attic air can reduce mold, mildew and stagnation through better ventilation of the attic, when moist warmer attic air transports into the building interior while being agitated by action of the present invention blower. Intake air filters ensure cleansing the humid air in normal HVAC fashion before supply to the building interior. There is a benefit to human comfort, during heating season, as humidity mixes with drier air inside a building structure. Interior air dryness is endemic during the heating season as traditional heating appliances operate in poorly ventilated building interior conditions closed to outside fresh air and lack of natural ventilation as windows are usually closed. Closing attic air vents therefore helps to reduce humidity in the attic air as a benefit while operation of the present invention also cause some increase of humidity in the building interior by transfer of such humidity, both desirable traits in the respective atmospheres of a building attic and interior space during the heating season, which is claimed.
14. A method as to claim 1 whereby the present invention HVAC apparatus is enclosed within the attic to provide a safe haven from outside weather elements and harmful solar radiation while also eliminating the need for ordinarily costly installation methods such as those required to secure externally mounted solar collector apparatus to rooftops or other building assemblies. Housing of the present invention HVAC elements within an enclosed attic avoids the cost of significant study and planning by professional engineers to determine weight factors and stress points of a building construction including calculations of capacity to hold weight during earthquakes, high winds, or snow conditions. A typical attic is already engineered and designed to support the heavy weight of roofing material with its structural and load bearing members, while the attic floor or ceiling structure is often used to contain HVAC appliances, duct systems, and storage of personal effects that would weigh much more than present invention HVAC components. Exterior mounted solar equipment is subject to effects of outside airborne chemical contaminants and dust that can be extremely harsh on such equipment. Further, externally mounted solar energy apparatus exposed to direct solar insolation and hot and cold temperatures can limit its operating lifetime affecting the long-term economics of the equipment. The current invention employs standard HVAC components designed for temperature extremes inside an attic where cooling season temperature excursions can increase to 60.0° C. (140° F.) or more, and heating season temperatures would dip below −18.0° C. (zero ° F.). Such HVAC components generally operate in a majority of building structures that contain attics/upper crawl spaces. The present invention demonstrates utility for the user by including components of reasonable cost that can withstand extremes of temperature and humidity to reduce potential for operational problems while being sheltered inside the attic with minimal weight distributed over the building structure, which is claimed.
15. A method as to claim 1 whereby scalability of the present invention apparatus enables collaboration with other solar heating modality such as a solar heat collector device for supplemental preheating to include the glazed or unglazed perforated solar heat collector (TSAC). The user can also combine the present invention system with a surface mounted solar collector placed outside the building to intake solar heated air through a duct inserted into a building structure attic vent with such heated air then merged. Supplemental heated air in the attic from external sources comes from concentrated form when using a heat exchanger or other externally mounted solar collector. Use of heat exchangers for heated air containment may be from a variety of solar heating units available in the marketplace. The user must be aware that solar collectors may provide only minimal Btu measure based on thermodynamic conduction and convection expected from such devices. Such collectors, however, would enhance solar heat gathering in partnership with the present invention apparatus regardless. The present invention system in partnership with other modality solar heating devices can result in increased solar space heating performance, which is claimed.
16. A method as to claim 3 using present invention computer programs to account for space heating energy cost savings versus cost of heat energy consumed in the resident traditional artificial heating appliance with such heat energy replaced by solar generated heat. Energy cost savings using the present invention requires measuring the psychrometric variable enthalpy, which determines the Btu/ft3 of air gathered by the system during operation. With such method, the consumer has the ability to calculate energy cost saving from measurement of attic air temperature and relative humidity monitored at their location by making recordings over relevant monthly periods during heating season. Such measurement enables determining energy value captured throughout the sunlight hours from start time to stop time of operation using the CFM airflow rate of the HVAC blower in the calculation. Monitoring of the temperature and relative humidity employs an inexpensive remote or wireless logging device that measures temperature and relative humidity in short intervals. The temperature/humidity logging device connects to a laptop or a desktop computer USB port for download of logged data. A dollar value in savings is determined from such logged data by measuring cost of heating fuel typically used to produce the same amount of Btu measure supplied at virtually zero cost for fuel using solar energy heated air. The cost savings of the present invention is readily accounted for using methods provided within the present invention computer programs for the benefit of the consumer, which is claimed.
17. A method as to claim 1 for selection of an air mover (blower) to produce required airflow velocity change of such blower thereby modifying heated air supply volume during space heating. A changing CFM airflow results through action of a variable speed control type motor engaged inside the blower activated by an independent controller that is computer programmed with necessary parameter HVAC operational factors. Variable airflow delivery can thereby provide additional flexibility in managing withdrawal of the limited resource of solar heated air within the attic, which is claimed.
Type: Application
Filed: Aug 26, 2015
Publication Date: Mar 2, 2017
Applicant: (Hesperia, CA)
Inventor: Clyde Wesley Smith, JR. (Hesperia, CA)
Application Number: 14/836,434
