A heat transfer system includes a steam chamber that communicates in an open-loop arrangement with a first steam source for supplying steam to the steam chamber, the steam chamber including a steam exit for supplying steam to air at atmospheric pressure. A heat transfer tube communicates in a closed-loop arrangement with a second steam source for supplying steam to an interior surface of the heat transfer tube, the heat transfer tube vaporizing condensate forming within the heat transfer system back to steam that is supplied to the air via the steam exit. The outer surface of the heat transfer tube is configured to contact the condensate and vaporize the condensate back into steam, wherein the heat transfer tube includes a plurality of pockets formed on the outer surface of the tube, each pocket including a pocket exit/entry portion having a smaller cross-sectional area than the cross-sectional area of the pocket at a root portion thereof adjacent the outer surface of the tube.

A heat exchanger having a heat transfer surface provided with hyperthermophilic bacteria. The hyperthermophilic bacteria can be from the genera Archaea. The hyperthermophilic bacteria can further be from the genus Sulfolobus, and the hyperthermophilic bacteria can further be from the species Sulfolobus solfataricus. The heat exchanger can be adapted to pool-boiling heat transfer.

An enhanced boiling apparatus includes a substrate having at least one heated region, at least one outer surface, and one or more asymmetric shaped cavities extending into the substrate along the at least one outer surface. Each of the one or more asymmetric shaped cavities has a sidewall which intersects at a corner with a bubble pathway surface with a different slope from the sidewall. Each of the asymmetric shaped cavities is configured to non-gravitationally direct fluid that is moving along the sidewall out along the bubble pathway surface.

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.

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.

A radiative cooling device and a radiative cooling method that effectively suppress ultraviolet light absorption. The radiative cooling device includes an ultraviolet reflection layer that reflects ultraviolet light UV, a light reflection layer that reflects visible light and infrared light, and an infrared radiative layer that radiates infrared light IR. Infrared light IR is radiated form a radiative surface. The ultraviolet reflection layer, the infrared radiative layer and the light reflection layer are laminated in this order as viewed from the side of the radiative surface.

A radiative cooling device and a radiative cooling method that effectively suppress ultraviolet light absorption. The radiative cooling device includes an ultraviolet reflection layer that reflects ultraviolet light UV, a light reflection layer that reflects visible light and infrared light, and an infrared radiative layer that radiates infrared light IR. Infrared light IR is radiated form a radiative surface. The ultraviolet reflection layer, the infrared radiative layer and the light reflection layer are laminated in this order as viewed from the side of the radiative surface.

One variation of a method for fabricating a dermal heatsink includes: fabricating a substrate defining an interior surface, an exterior surface opposite the interior surface, and an open network of pores extending between the interior surface and the exterior surface; activating surfaces of the substrate and walls of the open network of pores; applying a coating over the substrate to form a heatsink, the coating comprising a porous, hydrophilic material and defining a void network; removing an excess of the coating from the substrate to clear blockages within the open network of pores by the coating; hydrating the heatsink during a curing period; heating the heatsink during the curing period to increase porosity of the coating applied over surfaces of the substrate; and rinsing the heatsink with an acid to decarbonate the coating along walls of the open network of pores in the substrate.

A heat exchanger includes: a water-repellent coating film on part of a surface of the heat exchanger. The surface on which the water-repellent coating film is disposed includes a surface structure including protrusions. D/L<0.36, D/L>0.4×(L/H), D<200, L−D<1000, H>700, 0>1.28×D×10.sup.−2+2.77 ×(L−D)×10.sup.−3−1.1×D.sup.2×10.sup.−5−5.3×(L−D).sup.2×10.sup.−7−9.8×D×(L−D)×10.sup.−6−2.0, and 90°<θ<120°, where L is an average pitch of the protrusions in nm, D is an average diameter of the protrusions in nm, H is an average height of the protrusions in nm, and θ is a contact angle of water on a smooth plane of the water-repellent coating film.

A heat exchanger includes: a water-repellent coating film on part of a surface of the heat exchanger. The surface on which the water-repellent coating film is disposed includes a surface structure including protrusions. D/L<0.36, D/L>0.4×(L/H), D<200, L−D<1000, H>700, 0>1.28×D×10.sup.−2+2.77 ×(L−D)×10.sup.−3−1.1×D.sup.2×10.sup.−5−5.3×(L−D).sup.2×10.sup.−7−9.8×D×(L−D)×10.sup.−6−2.0, and 90°<θ<120°, where L is an average pitch of the protrusions in nm, D is an average diameter of the protrusions in nm, H is an average height of the protrusions in nm, and θ is a contact angle of water on a smooth plane of the water-repellent coating film.