A two-phase immersion type heat dissipation fin composite structure is provided. The two-phase immersion type heat dissipation fin composite structure includes a heat dissipation base layer, a bubble activation layer, and a fin structure. The fin structure and the bubble activation layer are both formed on the heat dissipation base layer, or the fin structure is formed on the bubble activation layer. The bubble activation layer is immersed in a two-phase coolant for increasing an amount of bubbles that is generated.

A vapor chamber includes a main body, a first vertical structure, and an enhanced boiling surface. The main body has a first surface and defines a first portion of an interior volume. The first vertical structure protrudes transverse to the main body and defines a second portion of the interior volume. The enhanced boiling surface is on at least a portion of the first vertical structure.

A radiative cooling composition comprises a first component having >55% reflectance in a wavelength range of 0.2 to 2.5 μm and a second component having >0.85 peak thermal emissivity for at least one wavelength in a range of 4-35 μm. A third pigmented component of the composition is configured to emit at least a fraction of absorbed energy, and in certain embodiments the pigmented component comprises at least one phosphor.

A radiative cooling composition comprises a first component having >55% reflectance in a wavelength range of 0.2 to 2.5 μm and a second component having >0.85 peak thermal emissivity for at least one wavelength in a range of 4-35 μm. A third pigmented component of the composition is configured to emit at least a fraction of absorbed energy, and in certain embodiments the pigmented component comprises at least one phosphor.

An outer finned tube includes a tube body, an outer wall of the tube body is provided with outer fins spirally arranged in an extension direction of the tube body; grid fins are arranged between two adjacent spiral parts of the outer fins correspondingly; two ends of each grid fin are connected to the two adjacent spiral parts of the corresponding outer fin respectively; a gap is kept between each grid fin and the outer wall of the tube body; and the plurality of grid fins are spaced in the extension direction of the tube body. An enhancing cavity is formed in an area defined by the outer wall of the tube body, inner walls of the grid fins and the outer fins in an encircling way, which can form a larger degree of superheat, provides a nucleation point for a boiling/condensation process and improves a heat exchange performance.

The present disclosure provides a radiative cooling metal plate, a preparation method and application thereof. The radiative cooling metal plate includes a metal substrate, a first adhesive layer and a radiative cooling functional layer stacked in order, the radiative cooling functional layer is located on a surface of the metal substrate, the first adhesive layer is arranged between the metal substrate and the radiative cooling functional layer, and an elongation at break of the radiative cooling functional layer is in a range of 1% to 300%. The radiative cooling functional layer can have sufficient ductility, and can have sufficient deformation to cope with the bending of the radiative cooling functional layer during pressing, such that the radiative cooling functional layer will not be damaged or broken, thereby ensuring the structural integrity of the radiative cooling functional layer and great radiative cooling effect of the metal substrate.

The radiative cooling device includes an infrared radiative layer A that radiates infrared light IR from a radiative surface H, a light reflective layer B disposed on a side opposite to the radiative surface H with respect to the infrared radiative layer A, and a protective layer D disposed between the infrared radiative layer A and the light reflective layer B. The infrared radiative layer A is a resin material layer J having a thickness adjusted so as to emit a heat radiation energy greater than an absorbed solar energy in a wavelength range from 8 μm to 14 μm. The light reflective layer B contains silver or a silver alloy, and the protective layer D is formed from a polyolefin based resin with a thickness of 300 nm or more and 40 μm or less or an ethylene terephthalate resin with a thickness of 17 μm or more and 40 μm or less.

A total heat exchange element includes partitions disposed in a state of being opposed to each other, and a spacer portion keeping a space between the partitions and forming a passage between the partitions. The spacer portion has a laminate structure in which nonwoven fabric base layers including a nonwoven fabric base material are laminated on both sides of a paper layer. A first nonwoven fabric base layer that is the nonwoven fabric base layer of the spacer portion laminated on one side of the paper layer is joined to the partition opposed to the first nonwoven fabric base layer, and a second nonwoven fabric base layer that is the nonwoven fabric base layer of the spacer portion laminated on another side thereof is joined to the partition opposed to the second nonwoven fabric base layer. The element has the above-mentioned configuration and so can improve the humidity exchange efficiency.

Fins are formed monolithically from the material of a tube body. The fins extend from the tube body outer surface, and include a fin base and a fin top. Wings extending from a fin side surface between the fin base and fin top can produce upper and lower channels between adjacent fins. Depressions can be formed in the fin top with platforms below the depressions. The tube can also include helical ridges on an inner surface of the tube. The tubes are used for heat transfer, and can be included in shell and tube heat exchangers.

A passive thermal management system and methods of using a thermoresponsive hydrogel coating configured to autonomously switch between a heating state and a cooling state based on ambient temperature. At temperature greater than a lower critical solution temperature of the thermoresponsive hydrogel, the thermoresponsive hydrogel coating becomes solar reflective and has enhanced radiative cooling ability to achieve daytime radiative cooling. At temperatures less than the lower critical solution temperature, the thermoresponsive hydrogel coating becomes transparent to facilitate absorption of solar radiation by sun absorber.