In one aspect the invention provides a heat transfer apparatus which includes a transmitter object which defines an external collection surface and an internal transmission surface. Also provided is a receiver object displaced from the transmitter object, the receiver object defining an internal receiving surface and an external heat delivery surface. A thermal conduit is provided which incorporates at least one side wall connected between the transmitter object and receiver object, this at least one side wall spanning the distance between the transmitter object and receiver object and enclosing a volume between the transmitter and receiver objects. This side wall or walls enclose the internal transmission surface of the transmitter object and the internal receiving surface of the receiver object. The transmitter object, receiver object and thermal conduit are configured to promote heat transfer predominantly towards the receiver object.

A heatsink comprising a heat exchange device having a plurality of heat exchange elements each having a surface boundary with respect to a heat transfer fluid, having successive elements or regions varying according to a fractal relationship. According to one embodiment, a noise spectrum due to fluid flow is wideband. According to another embodiment, surface boundary layers are disrupted to increase heat transfer. Flow-induced vortices may be generated at non-corresponding locations of the plurality of fractally varying heat exchange elements.

The present invention relates to a technique of cooling a temperature on the surface or under a material by emitting heat under a radiative cooling device to the outside while minimizing the absorption of light in a solar spectrum by forming a paint coating layer with excellent radiative cooling performance on various surfaces. A radiative cooling device according to an embodiment of the present invention may include a paint coating layer formed by coating or dyeing on various surfaces a paint solution mixed with nano or microparticles of which a particle size and a composition are determined in consideration of infrared emissivity and reflectance to incident sunlight in a wavelength range corresponding to a sky window and a binder mechanically connecting the surfaces of the nano or microparticles in a solvent.

Disclosed are systems and techniques for increasing heat transfer from a substrate to a working fluid. The systems may include a substrate comprising a plurality of grooves or cavities on at least one external surface. The system may also include an infusing liquid filling at least a majority of the plurality of grooves. The system may also include a working fluid configured to flow parallel to the external surface.

A heatsink comprising a heat exchange device having a plurality of heat exchange elements each having a surface boundary with respect to a heat transfer fluid, having successive elements or regions varying according to a fractal relationship. According to one embodiment, a noise spectrum due to fluid flow is wideband. According to another embodiment, surface boundary layers are disrupted to increase heat transfer. Flow-induced vortices may be generated at non-corresponding locations of the plurality of fractally varying heat exchange elements.

The present invention relates to a technical idea of cooling the surface of a material or the internal temperature under the material by emitting heat under an element to the outside while minimizing absorption of light in the solar spectrum, and more particularly to a technology for developing a material having a high transmittance or high reflectance with respect to incident sunlight and a high absorptivity selectively in a wavelength range of 8 μm to 13 μm corresponding to the sky window section of the atmosphere.

A composite material is applicable for photothermal energy conversion and thermal energy storage form-stable phase change. The composite material includes a supporting material and an organic phase-change material. The mass ratio of the supporting material to the organic phase change material is 3:7 to 1:9. The supporting material is lamellar, and the organic phase change material is evenly filled between supporting material layers to form a layered stacked structure. The supporting material is a nanosheet of Ti.sub.2C, Ti.sub.3C.sub.2, Ti.sub.3CN, V.sub.2C, Nb.sub.2C, TiNBC, Nb.sub.4C.sub.3, TA.sub.4C.sub.3, (Ti.sub.0.5Nb.sub.0.5).sub.2C, or (V.sub.0.5Cr.sub.0.5).sub.3C.sub.2. The organic phase-change material is paraffin, fatty acid, fatty acid ester or alcohol compound.

Processes produce a compound material structure by producing a composite material which extends along an axis of elongation from carbon nanostructures anchored in a matrix of a first metal extending along the axis of elongation of the composite material. The processes comprise dividing the composite material into segments of the composite material, arranging the segments in a plane of a die matrix, filling free spaces in the die matrix with a filler material and subsequently sintering in the die matrix to form a compound material structure or squeeze casting in the die matrix, and exposing the carbon nanostructures of the composite material on at least one surface of the compound material structure such that the carbon nanostructures protrude out of this surface. Compound material structures and uses thereof as a heat conductor and/or a heat exchanger are also provided.

Embodiments described herein relate a tunable heat transfer system. The tunable heat transfer system includes a controller, a first body, and a second body. The first body is communicatively coupled to the controller. The second body is communicatively coupled to the controller and spaced apart from the first body. The second body has a plurality of semimetal layers and a dielectric portion positioned between each of the plurality of semimetal layers. Each of the dielectric portions has a thickness to define a gap between each the plurality of semimetal layers in an expanded state and permitting each of the plurality of semimetal layers to abut each other in a contracted state. The controller is configured to change a near-field radiative heat transfer between the first body and the second body by changing the thickness of each of the dielectric portions between the expanded state and the contracted state.

A heat exchanger includes: a low temperature side channel through which low temperature liquid helium flows; a high temperature side channel through which high temperature liquid helium flows; and a thermal conduction unit that conducts heat from the high temperature side channel to the low temperature side channel. The thermal conduction unit has a partition member that separates the high temperature side channel and the low temperature side channel from each other and a thermal resistance reduction unit that reduces the thermal resistance between the partition member and the liquid helium. The thermal resistance reduction unit has a porous body having nano-size pores and fine metal particles having higher thermal conductivity than that of the porous body.