FABRICATION METHODS, STRUCTURES, AND USES FOR PASSIVE RADIATIVE COOLING

• US 20190316854A1
• Filed: 04/16/2019
• Published: 10/17/2019
• Est. Priority Date: 04/16/2018
• Status: Active Grant

• Current Assignee: Romy M. Fain
• Original Assignee: Romy M. Fain
• Inventors: Fain, Romy M.
• Granted Patent: US 11,473,855 B2
• Time in Patent Office: Days
• CPC Class Codes: B60H 1/00014 for load cargos on load transporting vehicles
• CPC Class Codes: B60H 1/32 Cooling devices B60H1/00478, B60H1/005 take precedence; vehicles adapted to transport refrigerated goods B60P3/20
• CPC Class Codes: C02F 1/14 using solar energy
• CPC Class Codes: E03B 3/28 from humid air condensing of vapours in general B01D5/00; dehumidification of air for air-conditioning F24F3/14
• CPC Class Codes: F24F 5/0089 Systems using radiation from walls or panels
• CPC Class Codes: F24S 70/225 for spectrally selective absorption
• CPC Class Codes: F25B 23/003 using selective radiation effect
• CPC Class Codes: F28F 13/18 by applying coatings, e.g. radiation-absorbing, radiation-reflecting; by surface treatment, e.g. polishing
• CPC Class Codes: F28F 13/185 Heat-exchange surfaces provided with microstructures or with porous coatings
• CPC Class Codes: F28F 21/02 of carbon, e.g. graphite
• CPC Class Codes: F28F 21/067 Details
• CPC Class Codes: F28F 2245/06 having particular radiating, reflecting or absorbing features, e.g. for improving heat transfer by radiation
• CPC Class Codes: G02B 3/0043 Inhomogeneous or irregular arrays, e.g. varying shape, size, height
• CPC Class Codes: G02B 3/0068 arranged in a single integral body or plate, e.g. laminates or hybrid structures with other optical elements G02B5/1885, G02B17/002, G02B30/27 take precedence
• CPC Class Codes: G02B 5/208 for use with infrared or ultraviolet radiation, e.g. for separating visible light from infrared and/or ultraviolet radiation
• CPC Class Codes: H01L 31/00 Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof H10K30/00 takes precedence; devices consisting of a plurality of solid state components formed in, or on, a common substrate, other than combinations of radiation-sensitive components with one or more electric light sources, H01L27/00
• CPC Class Codes: H01L 31/024 Arrangements for cooling, heating, ventilating or temperature compensation for photovoltaic devices H01L31/052
• CPC Class Codes: H01L 31/052 Cooling means directly associated or integrated with the PV cell, e.g. integrated Peltier elements for active cooling or heat sinks directly associated with the PV cells cooling means in combination with the PV module H02S40/42
• CPC Class Codes: H02S 40/42 Cooling means cooling means directly associated or integrated with the PV cell H01L31/052
• CPC Class Codes: H05K 7/20427 having radiation enhancing surface treatment, e.g. black coating
• CPC Class Codes: Y02A 20/00 : Water conservation; Efficient water supply; Efficient water use
• CPC Class Codes: Y02E 10/50 : Photovoltaic [PV] energy
• CPC Class Codes: Y02T 10/88 : Optimized components or subsystems, e.g. lighting, actively controlled glasses

Abstract

Passive radiative cooling structures and apparatus manufactured with such cooling structures conserve energy needs. A flexible film transparent to visible light incorporates particles at a volume percentage larger than 25% so as to absorb and emit infrared radiation at wavelengths where Earth'"'"'s atmosphere is transparent. Another film transparent to visible light is thin and flexible and configured to absorb and emit infrared radiation at wavelengths where Earth'"'"'s atmosphere is transparent, wherein etchings or depositions are present on one or both surfaces. A high efficiency cooling structure has an emissive layer sandwiched between a waveguide layer and a thermal conductive layer. A solar cell panel is covered by a transparent passive radiative cooling film. A container housing an active cooling unit incorporates passive radiative cooling structures on one or more exterior surfaces.

Claims

1. A passive radiative cooling structure comprising:

a flexible film, transparent to visible light, and incorporating a first material at a volume percentage larger than 25% so as to absorb and emit infrared radiation at wavelengths where Earth'"'"'s atmosphere is transparent;

wherein the flexible film includes a first surface parallel to a second surface, and an inner region between the first surface and the second surface.

2. A passive radiative cooling structure according to claim 1 wherein the flexible film comprises a flexible sheet of a second material that incorporates the first material as embedded particles having an average per particle volume greater than 14,200 μ

m³.

3. A passive radiative cooling structure according to claim 2 wherein the embedded particles are spherical particles.

4. A passive radiative cooling structure according to claim 3, wherein the spherical particles are polished or flash heated to minimize surface roughness.

5. A passive radiative cooling structure according to claim 2 wherein the embedded particles are curved-sidewall structures, each curved sidewall structure comprising a first circular area bounded by a first circular area circumference and a second circular area bounded by a second circular area circumference wherein the first circular area circumference and the second circular area circumference are connected by a concave surface, enclosing an inner volume connecting the first circular area and the second circular area;

and wherein the first circular area is oriented parallel with the first surface and the second circular region is oriented parallel with the second surface.

6. A passive radiative cooling structure of claim 1, positioned in proximity to a surface of a panel so as to cool solar cells in the panel sufficiently to increase the efficiency of the conversion of light to electrical energy.

7. A passive radiative cooling structure according to claim 2, the embedded particles occupying a volume percentage of the flexible film that is less than 73%.

8. A passive radiative cooling structure according to claim 1, further comprising a reflective backlayer in contact with the flexible film.

9. A passive radiative cooling structure according to claim 1, further comprising a window that is transparent to the wavelengths where the Earth'"'"'s atmosphere is transparent, wherein the window is fitted over the flexible film.

10. A passive radiative cooling structure comprising:

a flexible film, transparent to visible light, configured to absorb and emit infrared radiation at wavelengths where Earth'"'"'s atmosphere is transparent;

wherein the flexible film includes a first surface parallel to a second surface, and an inner region between the first surface and the second surface;

wherein the flexible film comprises a thin sheet of a first material, and wherein etchings are present on one or both of the first surface and the second surface.

11. A passive radiative cooling structure of claim 10, positioned in proximity to a surface of a panel so as to cool solar cells in the panel sufficiently to increase the efficiency of the conversion of light to electrical energy.

12. A passive radiative cooling structure of claim 10, wherein one or both of the first surface and the second surface are polished or flash heated to minimize surface roughness of the flexible film.

13. A passive radiative cooling structure of claim 10, further comprising a conforming material layer deposited on one or both of the first surface and second surface.

14. A passive radiative cooling structure of claim 10, further comprising a reflective backlayer in contact with the flexible film.

15. A passive radiative cooling structure according to claim 10, further comprising a window that is transparent to the wavelengths where the Earth'"'"'s atmosphere is transparent, wherein the window is fitted over the flexible film.

16. A passive radiative cooling structure comprising:

one or more cooling stacks;

wherein each cooling stack is configured with a first waveguide layer, a first emissive layer and a thermal conductive layer, wherein the first emissive layer is sandwiched between the first waveguide layer and the thermal conductive layer;

wherein the first emissive layer is configured to absorb and emit infrared radiation at wavelengths where Earth'"'"'s atmosphere is transparent;

wherein the thermally conductive layer has a proximal end and a distal end; and

wherein the thermally conductive layer is substantially perpendicular to and in thermal contact at its proximal end with a source of heat to be cooled.

17. A passive radiative cooling structure according to claim 16, wherein each cooling stack further comprises a second waveguide layer, and a second emissive layer;

wherein the second emissive layer is sandwiched between the second waveguide layer and the thermal conductive layer;

wherein the thermal conductive layer is sandwiched between the first emissive layer and the second emissive layer;

wherein the second emissive layer is configured to absorb and emit infrared radiation at wavelengths where Earth'"'"'s atmosphere is transparent.

18. A passive radiative cooling structure according to claim 16, wherein the first waveguide layer comprises one or more sub-layers to redirect thermal wavelengths of electromagnetic radiation towards the sky.

19. A passive radiative cooling structure according to claim 16, further comprising a window fitted over the radiative structure that is transparent to the wavelengths where the Earth'"'"'s atmosphere is transparent.