SOLAR AIR-HEATING SYSTEM
A roof-mounted solar air-heating system containing a solar absorber with at least one air manifold integrated structurally with the solar absorber to effect improved heat transfer efficiency and airspeed. The improved airspeed in combination with integrated air entrance and exit tubes improves solar-heated air displacement and temperature de-stratification in buildings without need for tie-in to other ventilation equipment.
This application claims the benefit of PPA application No. 61/021,984, filed Jan. 18, 2008 by the present inventor, which is incorporated by reference.
FEDERALLY SPONSORED RESEARCHNot Applicable
SEQUENCE LISTING OR PROGRAMNot Applicable
BACKGROUND OF THE INVENTION1. Field of the Invention
This invention generally relates to solar heating systems, specifically where heating is effected by air medium.
2. Prior Art
Glossary of Terms:
Air plenum: An air containment structure.
Building: Man-made roofed structure encompassing an open or closed space.
Collimated: Alignment of air movement in one consistent direction.
Communicating: Allowing air flow.
De-stratify: Unify air temperature at different heights in a space.
Manifold: Structure that divides and distributes airflow.
Solar absorber: Solid material that collects solar radiation and retains it as heat.
Solar heat collector: Structure that collects solar radiation and retains it as heat.
Streamlined: Quality of smooth or flowing contour designed for decreasing air resistance.
Ventilation equipment: Equipment for displacing air from one location to other locations.
Previously, advances in solar absorber materials have ensured efficient capture and retention of solar heat. These materials, usually termed “solar selective,” are commercially available for inclusion in solar-heating systems. When such material is heated by the sun, the heat can then be conducted to an air medium. Typically in this field, a stream of air impinging on the solar absorber, also variously termed “solar heat collector,” solar absorber plate,” “solar collector,” or “solar absorbing means,” carries heat to a building interior.
Previous art in this field has neglected efficiency in transfer of heat from solar absorber to the air medium. Air flow is forced through narrow openings and around sharp angles without the broadening and streamlining effect of air manifolds. This results in pressure loss, less heat exchanged, and lower heat output. Also neglected in prior art is effective air displacement into central areas of building spaces.
In U.S. Pat. No. 6,807,963 (2004) to Niedermeyer, air impinges on a solar heat collector without benefit of air manifolds. As a result, less air comes in contact with the solar heat collector during a given time interval, which reduces heat transfer efficiency. Furthermore, the solar heat collector will retain a greater amount of heat relative to ambient air temperature, an imbalance which encourages radiative heat losses. Also, the device lacks a clear means of displacing heated air into a building.
In U.S. Pat. No. 6,494,200 (2002) to Rylewski, air impinges on the solar absorber, termed “panel heated by solar radiation” without the benefit of air manifolds, which reduces heat transfer efficiency. Airflow is restricted to one side of the panel heated by solar radiation, further reducing heat transfer efficiency.
In U.S. Pat. No. 6,018,123 (2000) to Takada, Fukai, Mimura, Mori, and Shiomi, air impinges on a solar heat collector without benefit of air manifolds, which reduces heat transfer efficiency. Airflow is restricted to one side of the solar heat collector, further reducing heat transfer efficiency. Also, the suggested installation of the apparatus substantially flat on a low-sloping roof does not optimally expose the solar heat collector to low-angled winter sun.
In U.S. Pat. No. 5,596,981 (1997) to Soucy, air impinges on a solar absorber plate without benefit of air manifolds, which reduces heat transfer efficiency. Airflow is restricted to one side of the solar absorber plate, further reducing heat transfer efficiency.
In U.S. Pat. No. 5,657,745 (1997) to Damminger, airflow is restricted to one side of a solar heat absorption sheet. Also, the device lacks a clear means of displacing heated air to a building.
In U.S. Pat. No. 5,692,491 (1996) to Christensen, Kutscher, and Gawlik, an unglazed transpired solar collector lacks a clear means of displacing heated air to a building. Also, lack of glazing encourages conductive heat loss.
In U.S. Pat. No. 5,081,982 (1992) to MacKenzie, air movement depends on heat convection rather than active air impeller force. This limits the amount of air, in a given interval, impinging on a solar absorbing means. As a result, the solar absorbing means will retain a greater amount of heat relative to ambient air temperature, an imbalance which encourages radiative heat losses. Furthermore, lacking an air impeller, heated air from this device will convect up a wall rather than out into an occupied space. Also, the recommended placement of the device in a window blocks significant natural sunlight and heat.
SUMMARY OF THE INVENTIONMy invention is an improved solar air-heating system that significantly increases heat conversion efficiency and air displacement into buildings. The invention encourages air temperature destratification within building interiors without need for tie-in to additional ventilation equipment.
We will first look at one means of installation of a preferred embodiment of the invention in order to gain an overview. Reference is made to
In
Turning to
Now, we will turn to the construction of the invention. In
Solar absorber 39 consists of a rectangle of solar-selective foil and stands vertically on a long edge. Flat absorber plates 38A and 38B, each of substantially stiffer metal than solar absorber 39, are rectangular structural side extensions for absorber assembly 37, stand vertically on a short edge, and are substantially solar-selective.
Four sets of four, air vanes 42, 43, 44, and 45 are cut from thin aluminum flashing material in four graduated lengths, attached in order of length as matched pairs on opposite fields of metal plates 38A and 38B, each pair's bottom edges spaced at short, regular distances, and top edges spreading in an open-leaf profile. The attachment means can be with threaded rods, with welds, with high-temperature adhesives, or by molded integration with flat absorber plates 38A and 39B.
Absorber assembly 37 is integrated by fastening two rails 41 of right-angle metal stock along the rear top and bottom edges of metal plate 38A, solar absorber 39, and metal plate 38B. The finished outer dimensions of absorber assembly 37 must be slightly smaller than the corresponding dimensions of the opening in air plenum 31, shown in
In
When fastened to housing 28, retainer 48 holds nested assembly 27A together as shown in
Turning to
In
In
We now turn to the detailed operation of the installed invention as illustrated in the preferred embodiment. In
Electricity to electric fan 52 can be controlled externally by common electrical switches or thermostats, so that during periods when heat is not desired, active airflow will stop. In this inactive state, location of tubes 50 and 55 at a similar height in this embodiment discourages convective heat circulation through the invention.
The operational description above demonstrates the main purpose of the present invention, that is, to provide solar air heat with improved efficiency and displacement into buildings. The invention also provides air temperature de-stratification in buildings, according to the
It is well known that heat naturally rises via convection from lower air strata in buildings and then collects near the ceiling in an upper stratum. This presents two problems in colder weather for buildings and occupants: first, heat leaves the occupied lower air stratum, and second, heat is lost convectively through the roof.
From the description above, several advantages of the present invention become evident:
(a) The integration of manifold air races with the solar absorber reduces air turbulence and pressure loss, which increases heat transfer to the air medium.
(b) The open-leaf arrangement of manifold air races in the airflow path distributes air broadly across the solar absorber, which effectively increases heat transfer to the air medium.
(c) Airflow is enabled simultaneously across both sides of the solar absorber, which increases heat transfer to the air medium.
(d) The increased airspeed in the invention displaces solar-heated air far into a building interior.
(e) The presence of downward-extending air tubes in combination with increased airspeed encourages building air temperature de-stratification.
(f) The downward-extending air entrance and exit tubes terminate at substantially the same height, which discourages airflow from passive air convection when the fan is off and heat is not desired.
(g) Separate ductwork for the invention and tie-in with a building's existing ventilation system is obviated because of robust exit airspeed and collimation.
(h) The system is easily installed on low-rise building roofs.
(i) System components are nested in final assembly which saves manufacturing time and expense.
(j) The invention as described in the embodiments will withstand harsh outdoor conditions.
(k) Mirror surfaces are easily attached to the invention to augment solar exposure and thereby increase heat output.
The specific embodiments described herein should not be construed to:
(a) exclude use of other materials than those mentioned in the construction of the present invention,
(b) limit the position, shape, or number of manifold vanes,
(c) restrict the application of the invention, modified or unmodified, to building structures only,
(d) restrict the invention's purpose to that of providing heat to building occupants,
(e) limit the installation of the invention, modified or unmodified, to building roofs only,
(f) limit the shape and orientation of attached reflective augmenting surfaces.
(g) limit solar reception to one side only of the invention. For example, an embodiment of the invention with a double-side solar absorber: one side receives solar energy directly, and its opposite side simultaneously receives solar energy from reflective surfaces fixed near the invention.
(h) Limit the invention to a standalone form factor. For example the invention could be split into interconnected components, or the invention's separated components could be combined functionally with other devices.
Claims
1. An improved solar air-heating system comprising:
- a. an oblong air plenum with at least one transparent side that permits solar radiation,
- b. an entrance opening and an exit opening to the air plenum such that an air pathway is established substantially through the length of the plenum,
- c. a substantially flat absorber that heats when exposed to solar radiation and is positioned within the air plenum so that the field of the absorber stands vertically and divides the air pathway along its length,
- d. an air manifold intercepting the air pathway,
- whereby air, when forced through the air plenum will impinge upon a broader area of the solar absorber field and thereby speed heat conversion from the solar absorber, when it is heated by solar radiation, to the air.
2. The improved solar air-heating system of claim 1, further including an air exit tube that communicates with and extends downward from the air plenum exit opening, such that when the air plenum is installed above a building, the air exit tube will penetrate a corresponding and necessary pre-cut hole through the building's roof, and allow communication between the air plenum and the building's interior,
- whereby any airflow forced through the air plenum is collimated along the length of the air exit tube and thereby carries heat farther into the building interior.
3. The improved solar air-heating system of claim 1, further including an air entrance and an air exit tube each communicating with and extending downward from the corresponding air plenum's entrance and exit openings, such that when the air plenum is installed above a building, said tubes will penetrate corresponding and necessary pre-cut holes through the building's roof, allowing communication between the air plenum and the building's interior, so that when airflow is forced at a substantial speed through the air plenum, air from the air stratum that exists in the building's interior just under its roof enters the air entrance tube, flows through the air plenum, exits through the air exit tube, and penetrates substantially below said air stratum,
- whereby air temperature within the building will become destratified partially or completely.
4. An improved solar air-heating system comprising:
- a. an air plenum of substantially oblong box shape, that permits sunlight through a trans-parent sheet that forms one of the plenum's two long vertical sides,
- b. an entrance opening and an exit opening to the air plenum, both substantially round holes cut through the bottom side and at opposite ends of the air plenum, such that an air pathway is established through the length of the air plenum,
- c. a substantially flat absorber that heats when exposed to solar radiation and is positioned within the air plenum so that the field of the absorber sits vertically and divides the air pathway along its length,
- d. an air manifold in a position intercepting the air pathway just after the air entrance opening, consisting of a series of oblong vanes, each vane with its field perpendicular to the absorber and attached to it lengthwise, the vanes placed with their bottom short edges parallel and at substantially equal intervals across the air plenum's said openings, the vanes' parallel top edges fanning from their bottom edge origin across the height of the absorber field, where the vanes span the perpendicular distance between the absorber and one or other of the plenum's long vertical sides, so that absorber, vanes, and one or both of the plenum's long vertical sides enclose manifold air passageways,
- whereby each manifold will encourage airflow, when air is forced through the air plenum, across a broader area of the solar absorber field and thereby speed heat transfer from the solar absorber to the air.
5. The improved solar air-heating system of claim 4, further including an air exit tube that communicates with and extends downward from one of the air plenum openings, such that when the air plenum is deployed above a building, the air exit tube will install through a corresponding hole in the building roof and allow communication between the air plenum and the building interior,
- whereby any airflow forced through the air plenum is collimated by the air exit tube,
- and thereby displaces
- heat farther into the building interior.
6. The improved solar air-heating system of claim 4, further including an air entrance and an air exit tube each communicating with and extending downward from the corresponding air plenum's entrance and exit openings, such that when the air plenum is installed above a building, said tubes will penetrate corresponding and necessary pre-cut holes through the building's roof, and allow communication between the air plenum and the building's interior, so that when airflow is forced at a substantial speed through the air plenum, air from the air stratum that exists in the building's interior just under its roof enters and flows through the air plenum and subsequently penetrates substantially below said air stratum,
- whereby air temperature within the building will become destratified partially or completely.
Type: Application
Filed: Dec 25, 2008
Publication Date: Aug 6, 2009
Inventor: Joel Fairstein (Knoxville, TN)
Application Number: 12/344,224
International Classification: F24J 2/50 (20060101); F24J 2/24 (20060101);