APPARATUS AND METHOD FOR PASSIVELY COOLING AN INTERIOR
A system passively cools an interior area within a structure. The system includes a membrane assembly covering a portion of the structure, wherein the membrane has an interior side facing the interior area and an exterior side. The membrane assembly defines a plurality of pores. When a supply of fluid is provided to the membrane assembly, capillary action of the pores redistributes the fluid to create evaporation and, in turn, the desired heat flow. The membrane assembly can include an architectural membrane coated with a porous matrix coating to form the pores. A pump can provide the fluid to the interior side of the membrane assembly. Preferably, the architectural membrane is woven PTFE-coated fiberglass and the porous matrix coating is titanium dioxide and zeolites. The plurality of pores may have radii ranging from about 10 nanometers to 100 microns and a length of about 80 microns.
The subject disclosure relates to methods and systems for structure wall assemblies, and more particularly, to improved methods and systems for passively cooling an interior area of a structure.
2. Background of the Related ArtThe problems with high energy consumption of buildings and the harmful environmental emissions associated with air conditioning are well known. Residential and commercial buildings currently account for 72% of the nation's electricity use and 40% of its carbon dioxide (CO2) emissions each year, 5% of which comes directly from air conditioning. In addition, the refrigerants used in air conditioners are potent greenhouse gases (GHGs) that may contribute to global climate change.
Because the majority of cooling systems run on electricity, and most U.S. electricity comes from coal-fired power plants which produce CO2, there is a pressing need to support improvements that increase the efficiency of cooling technologies and reduce the use of GHG refrigerants.
In view of the above, there is a need for an interior cooling system that can reduce building energy consumption and environmental impact.
SUMMARYThe present disclosure is directed to a system and methods for passively cooling an interior area within a structure. The present disclosure provides cooling power to an interior area while using fewer harmful refrigerants and consuming less electrical energy than traditional methods.
In one embodiment, a system passively cools an interior area within a structure. The system includes a membrane assembly covering a portion of the structure, wherein the membrane has an interior side facing the interior area and an exterior side. The membrane assembly defines a plurality of pores. When a supply of fluid is provided to the membrane assembly, capillary action of the pores redistributes the fluid to create evaporation and, in turn, the desired heat flow. The membrane assembly can include an architectural membrane coated with a porous matrix coating to form the pores. A pump can provide the fluid to the interior side of the membrane assembly. Preferably, the architectural membrane is woven PTFE-coated fiberglass and the porous matrix coating is titanium dioxide and zeolites. The porous matrix coating can be comprised of several layers, said layers having pores with decreasing radii as they approach the exterior side of the membrane assembly. The plurality of pores may have radii ranging from about 10 nanometers to 100 microns and a length of about 80 microns. When saturated with liquid, a liquid content by mass of the porous matrix coating could be in a range of approximately 10-50%. Preferably, a tension system or a frame system supports the membrane assembly.
Another aspect of the subject disclosure is directed to a method for passively cooling an interior area within a structure. The method includes coating an architectural membrane with a porous matrix coating to form pores, covering a portion of the structure with the architectural membrane, and providing a fluid onto the architectural membrane such that capillary action of the pores redistributes the fluid to create evaporation and, in turn, heat flow out of the interior area. In one embodiment, the method calculates a setpoint for the interior area based upon empirical data related to a cooling profile of the interior area. The empirical data includes square footage of the membrane, temperature, humidity, wind and cloudiness. A cooling fluid, such as water, may be pumped onto the membrane assembly at varying degrees with a corresponding modification of the pumping based upon the setpoint. Typically, the pores redistribute the fluid laterally along the same side of the architectural membrane. The pores may redistribute the fluid from an interior side of the architectural membrane to an exterior side of the architectural membrane, or vice versa. The coating step may include depositing a concentrated slurry including a binding agent and zeolites on the architectural membrane, then heating the concentrated slurry to set the binding agent and form the porous matrix. The concentrated slurry may include titanium dioxide as a self cleaning agent. In one embodiment, the method calculates an overall heat transfer coefficient (U-value) for the structure; and calculating a setpoint based upon the U-value.
Still another embodiment of the subject technology is directed to a structure for passively cooling an interior area comprising: a wall structure having a frame, a membrane assembly covering a portion of the frame, wherein the membrane assembly defines a plurality of pores, and a liquid on the membrane assembly such that capillary action of the membrane assembly pores spreads the liquid to create evaporation and, in turn, cooling. A fan system may increase air flow across the membrane assembly and/or provide airflow across the membrane assembly for delivery to a heating and ventilation system. The pores can extend from an interior side to an exterior side of the membrane assembly and the membrane assembly can include an architectural membrane coated with a porous matrix coating to form the pores.
It should be appreciated that the subject technology can be implemented and utilized in numerous ways, including without limitation as a process, an apparatus, a system, a device, a method for applications now known and later developed such as a computer readable medium and a hardware device specifically designed to accomplish the features and functions of the subject technology. These and other unique features of the system disclosed herein will become more readily apparent from the following description and the accompanying drawings.
So that those having ordinary skill in the art to which the disclosed system appertains will more readily understand how to make and use the same, reference may be had to the following drawings.
The subject technology overcomes many of the prior art problems associated with cooling building interiors by using architectural membranes and membrane-based wall assemblies with nanoporous coatings. The advantages, and other features of the technology disclosed herein, will become more readily apparent to those having ordinary skill in the art from the following detailed description of certain preferred embodiments taken in conjunction with the drawings which set forth representative embodiments of the present disclosure and wherein like reference numerals identify similar structural elements. It is understood that references to the figures such as interior, exterior, up, down, upward, downward, left, and right are with respect to the figures and not meant in a limiting sense.
Referring now to
In one embodiment, the house 100 includes a water pump 130 connected to a supply of water such as a well or municipal source. Greywater may also be used instead of, or in addition to, other water sources to reduce, or even eliminate, the strain on water resources. The water pump 130 provides water to the membrane assembly 110. Additionally, water can reach the membrane assembly 110 by, for example, spraying water along membrane assembly 110, dripping water along membrane assembly 110, or through the water content of air as the air flows along the membrane assembly 110. As water evaporates from the membrane assembly 110, the latent heat of vaporization is extracted, some of it from the interior, generating cooling power on the order of hundreds of Watts per Square meter. The evaporation rate increases with temperature, thus, the potential to passively cool the interor increases with temperature as well.
Referring now to
A membrane assembly 210 is spaced from the cladding 206 to form an air gap 208. The air gap 208 allows upward air flow, depicted by arrow “a”, between cladding 206 and the membrane assembly 210. The air flow may move in any direction and is preferably driven by an air handler including a fan.
The membrane assembly 210 includes an architectural fabric layer 212 having a coating 218, shown here on the exterior of the membrane assembly 210. The architectural fabric layer 212 may be formed using typical commercial architectural materials for exterior membranes, for example, woven polytetrafluoroethylene coated fiberglass. The membrane assembly may also use a more rigid base layer instead of architectural fabric depending upon the particular application and building structure.
The coating 218 defines a plurality of pores 216 which absorb and distribute water across the membrane assembly 210 through capillarity to enhance evaporation of water applied thereto. The coating 218 may be any material which allows for water distribution, preferably through capillary effect, such as a porous ceramic. Capillary effect spreads the water applied to the coating 218 over a wide area to replenish what is lost to evaporation. Alternatively, the coating 218 may be a different material which allows water distribution such as cloth, hydrogels, or cellulite.
At temperatures where building cooling is desired, evaporation of water applied from the coating 218 causes heat to flow from the air gap 208 through the membrane assembly 210, shown by arrow “b”. Additionally, evaporation causes heat flow from the membrane assembly 210 out of the wall assembly 200, as shown by arrow “c”. Thus, the latent heat of vaporization extracts heat as shown by heat flow arrows “b” and “c”, cooling the air gap 208. The cooling air gap, in turn, cools the interior of the building 600B and reduces the cooling load for maintaining the interior 602 at the desired temperature.
Referring now to
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The wall assemblies 400A-B depict possible locations for the coating 418A-B. The coating 418A-B may be applied to one of the various layers of walls assemblies 418A-B, including for example, along the siding, the exterior insulation, and/or the cladding. Multiple coatings may be present, say for example, on each side of the air gaps 408A-B.
In the wall assembly 400A of
In the wall assembly 400B, the membrane assembly 410B includes an architectural fabric layer 412B with an inner coating 418B. The coating 418B runs along the interior side 417B of membrane assembly 410B, directly adjacent to air gap 408B, facilitating water distribution and evaporation along the interior side 417B of the membrane assembly 410B. In the configuration shown in these wall assemblies 400A, 400B, evaporation causes the air in the air gaps 408A, 408B to be cooled directly while also being made more humid.
Referring now to
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Evaporatively cooled air from the air gap 508B travels between cladding 506B and the membrane assembly 510B, as depicted by arrow “g”, and into a heat exchanger 532B. Outside air enters a ventilation duct 536B, as shown by arrow “h”. The air in the ventilation duct 536B is moved through the heat exchanger 532B, and exits the heat exchanger 532B, as shown by arrow “i”.
In the heat exchanger 532B, the cooled air from the air gap 508a circulates around the ventilation duct 536B and, in turn, cools the air in the ventilation duct 536B. In this way, the air passing through the heat exchanger 532B via the ventilation duct 536B is cooled by the air from the air gap 508A. The air exiting the heat exchanger 532B may directly cool the interior or pass into a ventilation unit, such as an air conditioner to provide pre-cooled air thereto. By passing the evaporatively cooled air from the air gap 508B through the heat exchanger 532B to cool the air in the ventilation duct 536B, the energy required to cool the interior is reduced.
Referring now to
Similar to the other embodiments mentioned herein, evaporative cooling from the membrane assembly 510C causes cooling of the air in air gap 508C. Cooled air from the air gap 508C travels, as shown by arrows “a”, between membrane assembly 510C and the cladding 506C, and into the condenser assembly 542C. The condenser assembly 542C operates by cooling and condensing refrigerant in the coil assembly 546C. As the refrigerant is cooled in the condenser assembly 542C, heat in the form of hot air exits to the exterior, as shown by arrow “j”.
By providing cooled air from air gap 508C to the condenser assembly 542C, rather than outside air, the efficiency of the condenser assembly 542C is improved. Cooled refrigerant from the condenser assembly 542C is then returned to the air handler assembly 540C, via the coil assembly 546C. Air from the interior of the structure enters the air handler assembly 540C, as shown by arrow “k”, and, in turn, is cooled by passing over the coil assembly 546C. After being cooled such air is then passed back into the interior as shown by arrow “l”.
It would be understood by one skilled in the art that the embodiments shown in
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At step 704, a portion of a structure is covered with the architectural membrane. The structure may be any of the wall assemblies above, variations thereof, and other structures as would be appreciated by those of ordinary skill in the art based upon review of the subject disclosure. At step 706, a fluid is provided onto the architectural membrane such that capillary action of the pores redistributes the fluid to create evaporation and, in turn, heat flow out of the interior area of the structure.
In one embodiment, a set point temperature for the interior area can be calculated based on empirical data related to a cooling profile. Relevant data related to a cooling profile may include, for example, square footage of the membrane, temperature, humidity, wind, cloudiness, the type of cooling fluid, the method and rate of administration of the cooling fluid, and/or empirical performance data. The setpoint may also be based on the overall heat transfer coefficient, or U-value. Fluid may then be distributed, in accordance with step 706, by pumping fluid across the membrane at a varying rate based upon the setpoint.
Referring now to
It is envisioned that the air conditioning unit, water pump, thermostat control and the like would include electronics such as a processor and memory to form a controller for utilizing the setpoint for control. Additionally, user interfaces in the form of displays, buttons, scanners, usb ports and the like would be incorporated to input and output data. Additionally, the controller could have wireless capabilities for interaction with a network, smartphone, tablet and the like for additional input and output of data and information.
It will be appreciated by those of ordinary skill in the pertinent art that the functions of several elements may, in alternative embodiments, be carried out by fewer elements, or a single element. Similarly, in some embodiments, any functional element may perform fewer, or different, operations than those described with respect to the illustrated embodiment. Also, functional elements (e.g., structural elements, sheaths, vapor barriers, water barriers, wind barriers, cladding and the like) shown as distinct for purposes of illustration may be incorporated within other functional elements in a particular implementation.
While the subject technology has been described with respect to preferred embodiments, those skilled in the art will readily appreciate that various changes and/or modifications can be made to the subject technology without departing from the spirit or scope of the invention as defined by the appended claims.
Claims
1. A system for passively cooling an interior area within a structure comprising:
- a membrane assembly covering a portion of the structure, wherein the membrane assembly has an interior side facing the interior area and an exterior side, the membrane assembly defines a plurality of pores; and
- a supply of fluid provided to the membrane assembly such that capillary action of the pores redistributes the fluid to create evaporation and, in turn, heat flow.
2. A system as recited in claim 1, wherein: the membrane assembly includes an architectural membrane coated with a porous matrix coating to form the pores, and
- further comprising a pump for providing the fluid to the interior side of the membrane assembly.
3. A system as recited in claim 2, wherein the architectural membrane is woven PTFE-coated fiberglass and the porous matrix coating is titanium dioxide and zeolites.
4. A system as recited in claim 2, wherein the porous matrix coating is comprised of several layers, said layers having pores with decreasing radii as they approach the exterior side of the membrane assembly.
5. A system as recited in claim 1, wherein the plurality of pores have radii ranging from about 10 nanometers to 100 microns and a length of about 80 microns.
6. A system as recited in claim 2, wherein when saturated with liquid, a liquid content by mass of the porous matrix coating is in a range of approximately 10-50%.
7. A system as recited in claim 1, further comprising a tension system for supporting the membrane assembly.
8. A system as recited in claim 1, further comprising a frame system for supporting the membrane assembly.
9. A method for passively cooling an interior area within a structure, the method comprising the steps of:
- coating an architectural membrane with a porous matrix coating to form pores;
- covering a portion of the structure with the architectural membrane; and
- providing a fluid onto the architectural membrane such that capillary action of the pores redistributes the fluid to create evaporation and, in turn, heat flow out of the interior area.
10. A method as recited in claim 9, further comprising the step of calculating a setpoint for the interior area based upon empirical data related to a cooling profile of the interior area, wherein the empirical data includes square footage of the membrane, temperature, humidity, wind and cloudiness.
11. A method as recited in claim 10, further comprising the steps of pumping the fluid onto the membrane assembly at a variable rate based upon the setpoint.
12. A method as recited in claim 9, wherein when saturated with liquid, a liquid content by mass of the porous matrix coating is approximately 10 to 50% and further comprising the step of varying the liquid content based upon a setpoint.
13. A method as recited in claim 9, wherein the pores redistribute the fluid from an interior side of the architectural membrane to an exterior side of the architectural membrane.
14. A method as recited in claim 9, wherein the coating step includes depositing a concentrated slurry including a binding agent and zeolites on the architectural membrane, then heating the concentrated slurry to set the binding agent and form the porous matrix.
15. A method as recited in claim 14, wherein the concentrated slurry includes titanium dioxide as a self cleaning agent.
16. A method as recited in claim 9, further comprising the step of calculating an overall heat transfer coefficient (U-value) for the structure; and calculating a setpoint based upon the U-value.
17. A structure for passively cooling an interior area comprising:
- a wall structure having a frame;
- a membrane assembly covering a portion of the frame, wherein the membrane assembly defines a plurality of pores; and
- a liquid on the membrane assembly such that capillary action of the membrane assembly pores spreads the liquid to create evaporation and, in turn, cooling.
18. A system as recited in claim 17, further comprising a fan system for increasing air flow across the membrane assembly.
19. A system as recited in claim 17, further comprising a fan system for providing airflow across the membrane assembly for delivery to a heating and ventilation system. 20.
- a sustem as recited in claim 17, wherein the pores extend from an interior side to an exterior side of the membrane assembly and the membrane assembly includes an architectural membrane coated with a porous matrix coating to form the pores, and
- further comprising: a pump for providing the liquid; a fan system for providing airflow across the membrane assembly and into a heating and ventilation system; and a microcontroller for calculating a setpoint for the interior area based upon empirical data related to a cooling profile of the interior area.
Type: Application
Filed: Apr 7, 2016
Publication Date: Aug 9, 2018
Inventor: Derek Martin Stein (Providence, RI)
Application Number: 15/506,074