APPARATUS AND METHOD FOR PASSIVELY COOLING AN INTERIOR

• US 20170167738A1
• Filed: 02/27/2017
• Published: 06/15/2017
• Est. Priority Date: 04/07/2015
• Status: Active Grant

• Current Assignee: Brown University
• Original Assignee: Brown University
• Inventors: Stein, Derek Martin
• Granted Patent: US 10,704,794 B2
• Time in Patent Office: Days
• CPC Class Codes: E04B 1/74 Heat, sound or noise insulation, absorption, or reflection forms of, or arrangements in, rooms for influencing or directing sound E04B1/99; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls fire protection E04B1/94; elements chiefly adapted for structural purposes E04C1/00 - E04C3/00; chiefly adapted for surface coverings E04F13/00; as underlayers for floor coverings E04F15/18; closures for wall or like openings E06B
• CPC Class Codes: E04C 2/28 combinations of materials fully covered by groups E04C2/04 and E04C2/08
• CPC Class Codes: F24F 13/0227 using parts of the building, e.g. air ducts inside the floor, walls or ceiling of a building
• CPC Class Codes: F24F 2003/1435 comprising semi-permeable membrane
• CPC Class Codes: F24F 2005/0082 Facades
• CPC Class Codes: F24F 2221/17 mounted in a wall
• CPC Class Codes: F24F 3/1411 by absorbing or adsorbing water, e.g. using an hygroscopic desiccant
• CPC Class Codes: F24F 5/0035 using evaporation
• CPC Class Codes: Y02B 30/54 Free-cooling systems

Abstract

A system passively cools, regulates humidity and/or rectifies diffusive transport of water vapor in 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 cooling, a supply of fluid is provided to the membrane assembly so that 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, zeolites and/or silica gel.

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.

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 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; and

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 selected from the group consisting of titanium dioxide, zeolites, silica gel and combinations thereof.

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 porous matrix coating includes a polymer or resin used as a binder to adhere silica gel particles and the architectural membrane is fabricated from a nylon/polyamide membrane.

6. A system as recited in claim 1, wherein the porous matrix coating includes a paint used as a binder to adhere silica gel particles to the architectural membrane.

7. A method for passively regulating a relative humidity of an interior area within a structure, the method comprising the steps of:

forming an architectural membrane with first and second membranes separated to form a space therebetween, the first membrane being a vapor barrier;

filling the space with a high water vapor permeability material;

coating the second 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.

8. A method as recited in claim 7, further comprising the step of embedding silica gel particles directly in the first membrane as the first membrane is formed, wherein the first membrane is nylon.

9. A method as recited in claim 8, further comprising the step of coating the first membrane with silica gel particles and then applying heat.

10. A method as recited in claim 7, wherein the high water vapor permeability material is selected from the group consisting of fiberglass and rock wool.

11. A method as recited in claim 7, further comprising the step of applying electric fields to the first membrane to promote adhesion of a slurry of silica gel particles thereto.

12. A method as recited in claim 7, further comprising the step of growing a layer of silica gel on the first membrane by coating one side of the membrane with a silica gel solution followed by evaporation.

13. A method as recited in claim 7, wherein the membrane varies in permeability with changes in humidity and temperature to keep out unwanted vapor.

14. A method as recited in claim 7, wherein the pores redistribute the fluid from an interior side of the architectural membrane to an exterior side of the architectural membrane.

15. A structure for rectifying diffusive transport of water vapor into an interior area of an enclosure comprising:

a wall structure having a frame; and

a membrane assembly covering a portion of the frame to form the enclosure, wherein the membrane assembly has;

an interior side and an exterior side;

a porous layer on the interior side with a high capacity for water adsorption; and

a water vapor layer on the exterior side that is a high vapor barrier at low relative humidity and become more water permeable at high relative humidity.

16. A structure as recited in claim 15, wherein the porous layer defines a plurality of pores that spread liquid.

17. A structure as recited in claim 15, further comprising a liquid on the membrane assembly such that capillary action of the membrane assembly pores to create evaporation and, in turn, cooling.

18. A structure as recited in claim 15, wherein the pores spread liquid by branching into smaller channels.

19. A structure as recited in claim 15, further comprising a fan system for increasing air flow across the membrane assembly.