Granted Patent B1

US 12,745,341 · App. 19/391,836 · Granted Sep 22, 2026

Inventors: Hafiz Muhammad Ali (Dhahran, SA); Qamar Abbas (Dhahran, SA)

Assignee: King Fahd University of Petroleum and Minerals

H05K1/0201

Abstract

Claims (61)

1 . A passive radiative cooling system for cooling a printed electronic circuit, comprising;

a thermally insulated box having walls and a floor, wherein an inner surface of the walls and the floor are coated with a reflective tape;

a cone-shaped aluminum reflector located within an inner cavity of the thermally insulated box, wherein the cone-shaped aluminum reflector is attached to the floor and has a central axis coincident with a central axis of the thermally insulated box;

a polydimethylsiloxane (PDMS)-coated aluminum double-sided flat thermal emitter placed vertically within the cone-shaped aluminum reflector, wherein a vertical axis of the PDMS-coated aluminum double-sided flat thermal emitter is coincident with the central axis of the cone-shaped aluminum reflector;

at least one printed electronic circuit directly printed on or attached to a polished aluminum substrate of the PDMS-coated aluminum double-sided flat thermal emitter; and

a transparent polyethylene sheet configured to cover a top opening of the thermally insulated box.

2 . The passive radiative cooling system of claim 1 , wherein the passive radiative cooling system is configured to reduce a temperature within the thermally insulated box by an average of about 10 degrees Celsius below an ambient temperature which surrounds the thermally insulated box.

3 . The passive radiative cooling system of claim 2 , wherein the PDMS-coated aluminum double-sided flat thermal emitter is configured to emit heat within an atmospheric transparency window wavelength having a range of about 8 μm to about 13 μm.

4 . The passive radiative cooling system of claim 1 , wherein the thermally insulated box:

is made from polystyrene foam;

the polystyrene foam has a thickness of about 10 mm;

has a rectangular cuboid shape of about 500 mm by about 400 mm by about 300 mm; and

has an open top end.

5 . The passive radiative cooling system of claim 1 , wherein a frustum angle of the cone-shaped aluminum reflector is about 45 degrees.

6 . The passive radiative cooling system of claim 1 , wherein the PDMS-coated aluminum double-sided flat thermal emitter is fabricated from the polished aluminum substrate coated with a PDMS layer on each of a first side and a second side, wherein the polished aluminum substrate is about 0.5 mm in thickness.

7 . The passive radiative cooling system of claim 6 , wherein:

the PDMS-coated aluminum double-sided flat thermal emitter is mounted within the thermally insulated box with the first side and the second side facing the cone-shaped aluminum reflector; and

the PDMS-coated aluminum double-sided flat thermal emitter is attached to the floor by a high-temperature silicone adhesive.

8 . The passive radiative cooling system of claim 7 , wherein a length of the PDMS-coated aluminum double-sided flat thermal emitter is equal to a height of the cone-shaped aluminum reflector as measured from the floor of the thermally insulated box to an upper rim of the cone-shaped aluminum reflector.

9 . The passive radiative cooling system of claim 8 , wherein the PDMS-coated aluminum double-sided flat thermal emitter has a width of about 80 mm and the length is about 140 mm from the floor of the thermally insulated box.

10 . The passive radiative cooling system of claim 6 , wherein:

the at least one printed electronic circuit is directly printed on at least one of the first side and the second side of the polished aluminum substrate, wherein each printed electronic circuit includes at least one contact pad configured for connection to at least one of a power source and an input/output line;

a first PDMS layer is coated on the first side of the polished aluminum substrate, wherein the first PDMS layer is about 120 microns thick, wherein the first PDMS layer is cured on the first side for about 60 minutes at 100 degrees Celsius; and

a second PDMS layer is coated on the second side of the polished aluminum substrate, wherein the second PDMS layer is about 120 microns thick, wherein the second PDMS layer is cured on the second side for about 60 minutes at 100 degrees Celsius.

11 . The passive radiative cooling system of claim 10 , further comprising:

a plurality of vias formed in each PDMS layer to expose each one of the at least one contact pad; and

a plurality of wiring configured to connect each contact pad to at least one of an external power source and an external input/output controller.

12 . The passive radiative cooling system of claim 6 , wherein:

the at least one printed electronic circuit is attached to at least one of the first side and the second side of the polished aluminum substrate, wherein each printed electronic circuit includes at least one contact pad configured for connection to at least one of a power source and an input/output line;

a first PDMS layer is coated on a first side of the polished aluminum substrate, wherein the first PDMS layer is about 120 microns thick, wherein the first PDMS layer is cured on the first side for about 60 minutes at 100 degrees Celsius; and

a second PDMS layer is coated on a second side of the polished aluminum substrate, wherein the second PDMS layer is about 120 microns thick, wherein the second PDMS layer is cured on the second side for about 60 minutes at 100 degrees Celsius.

13 . The passive radiative cooling system of claim 12 , further comprising:

a plurality of vias formed in each PDMS layer to expose each one of the at least one contact pad; and

a plurality of wiring configured to connect each contact pad to at least one of an external power source and an external input/output controller.

14 . A method of making a passive radiative cooling system for cooling at least one printed electronic circuit, comprising;

coating an inner surface of walls and a floor of a thermally insulated box with a reflective tape;

attaching a cone-shaped aluminum reflector located within an inner cavity of the thermally insulated box to the floor with a central axis of the cone-shaped aluminum reflector coincident with a central axis of the thermally insulated box;

directly printing or attaching at least one printed electronic circuit on a polished aluminum substrate;

forming a polydimethylsiloxane (PDMS)-coated aluminum double-sided flat thermal emitter by coating the polished aluminum substrate with a PDMS layer;

placing the PDMS-coated aluminum double-sided flat thermal emitter vertically within the cone-shaped aluminum reflector, wherein a vertical axis of the PDMS-coated aluminum double-sided flat thermal emitter is coincident with the central axis of the cone-shaped aluminum reflector; and

covering a top opening of the thermally insulated box with a transparent polyethylene sheet.

15 . The method of claim 14 , further comprising:

directly printing the at least one printed electronic circuit on at least one of a first side and a second side of the polished aluminum substrate, wherein each printed electronic circuit includes at least one contact pad configured for connecting to at least one of a power source and an input/output line.

16 . The method of claim 15 , further comprising coating the PDMS layer by:

coating a first PDMS layer on the first side of the polished aluminum substrate, wherein the first PDMS layer is about 120 microns thick;

curing the first PDMS layer for about 60 minutes at 100 degrees Celsius; and

coating a second PDMS layer on the second side of the polished aluminum substrate, wherein the second PDMS layer is about 120 microns thick; and

curing the second PDMS layer for about 60 minutes at 100 degrees Celsius.

17 . The method of claim 16 , further comprising:

forming a via in each PDMS layer over each contact pad; and

connecting, by wires, each contact pad to one of an external power source and an external input/output controller.

18 . The method of claim 14 , further comprising:

attaching the at least one printed electronic circuit to at least one of a first side and a second side of the polished aluminum substrate, wherein each printed electronic circuit includes at least one contact pad configured for connecting to at least one of a power source and an input/output line.

19 . The method of claim 15 , further comprising coating the PDMS layer by:

coating a first PDMS layer on the first side of the polished aluminum substrate, wherein the first PDMS layer is about 120 microns thick;

curing the first PDMS layer for about 60 minutes at 100 degrees Celsius;

coating a second PDMS layer on the second side of the polished aluminum substrate, wherein the second PDMS layer is about 120 microns thick; and

curing the second PDMS layer for about 60 minutes at 100 degrees Celsius.

20 . The method of claim 19 , further comprising:

forming a via in each PDMS layer over each contact pad; and

connecting, by wires, each contact pad to at least one of an external power source and an external input/output controller.

Assignments (1)

References Cited (8)