A heat exchanger capable of automatically defrosting or deicing includes row tubes and fins. A refrigerating medium can be led into the row tubes. The fins are arranged on an outer wall of the row tube. And heights of the fins extend in a radial direction of the row tube. Each of the fins include a first heat conducting part and a second heat conducting part that are connected with the row tube in sequence. A thermal conductivity of the second heat conducting part is smaller than a thermal conductivity of the first heat conducting part and a thermal conductivity of the row tube. An outer surface of the first heat conducting part and an outer surface of the row tube are both coated with a micron or nanometer hydrophobic layer, which is a hydrophobic coating or a hydrophobic oil film.

A heat sink includes a bottom plate, a liquid barrier structure and a microstructure used for heat dissipation. The liquid barrier wall is arranged on the bottom plate. The liquid barrier wall is closed on the bottom plate to form a container. The microstructure for heat dissipation is arranged in the container and includes porous materials or 3D-structures with small sizes.

A heat sink includes a bottom plate, a liquid barrier structure and a microstructure used for heat dissipation. The liquid barrier wall is arranged on the bottom plate. The liquid barrier wall is closed on the bottom plate to form a container. The microstructure for heat dissipation is arranged in the container and includes porous materials or 3D-structures with small sizes.

A heat exchanger is provided. The heat exchanger includes a configuration in which a heat transfer tube having a flat shape passes through a plurality of fins, and capable of securing drainage performance of condensed water retained on a surface of the heat transfer tube while improving a heat transfer rate, and further capable of suppressing an increase in ventilation resistance. The heat exchanger includes a heat transfer tube formed in a flat shape, and a plurality of fins, and a refrigerant flowing inside the heat transfer tube exchanges heat with air flowing between the plurality of fins. The fin includes a heat transfer expansion surface including a peak portion and a valley portion provided along an air flow direction, and a drain structure provided to overlap the heat transfer expansion surface.

Systems and techniques are described that provide for enhanced gain and radiation characteristics of antennas. The systems and techniques employ layers or cards of fractal plasmonic surfaces to provide gain to the antennas. The fractal plasmonic surfaces each include a close-packed arrangements of resonators having self-similar or fractal shapes, which may be referred to as “fractal cells.” The cards can be held by a frame adapted to fit an antenna. The FPS cards can provide benefits for gain, field emission, directivity, increased bandwidth, power delivery, and/or heat management. One or more dielectric layers or cards may be used to enhance gain and/or directivity characteristics.

An electric motor may include a stator assembly comprising a stator housing, and one or more rotors coupled to the stator by a rotor shaft assembly. The stator housing may include a cooling structure that has a plurality of cooling body portions and a plurality of cooling conduits defined by the plurality of cooling body portions. A method of forming a stator housing for an electric machine may include additively manufacturing a stator housing that includes a cooling structure defining a fluid domain, coupling a working fluid source to the stator housing and introducing a working fluid into the fluid domain defined by the cooling structure, and sealing the cooling structure with the working fluid contained within the fluid domain of the cooling structure. A method of cooling an electric machine may include heating the working fluid in the fluid domain and flowing the working fluid through the fluid domain, and transferring heat from the cooling structure to a cooling fluid flowing along one or more cooling surfaces contacting a surface of the electric machine.

A fin, comprising: multiple fin subunits arranged in multiple rows, the fin subunits in two adjacent rows being arranged in an offset fashion. Each of the fin subunits comprises: a first direction center line and a second direction center line perpendicular to the first direction center line; a hole located at a central part of the fin subunit; four fenestrated zones, with two adjacent fenestrated zones in the four fenestrated zones being arranged as mirror images of each other, centered at the first or second direction center line therebetween; a flat zone comprising a hole periphery flat zone, the hole periphery flat zone being disposed between the hole and each fenestrated zone; each fenestrated zone comprises first, second, third and fourth boundaries, wherein the first boundary is located at that side of each fenestrated zone which faces the hole, the second boundary is located at that side of each fenestrated zone which faces away from the hole, and the third and fourth boundaries extend in a direction parallel to the first direction center line; the first boundary forms a demarcation line between the hole periphery flat zone and each fenestrated zone, and at least a portion of the first boundary is an elliptical arc or a circular arc that is not concentric with the circle center of the hole.

A heat exchange area (4) of a heating plate (1) of a plate heat exchanger having corrugations, wherein the corrugations have additional local corrugations on their front and/or side surfaces forming notches (45, 4F) and the apex line (4L) of the corrugations has discontinuous form, preferably it is a polygonal curve or a wavy line.

A planar fin for use in a heat sink includes turbulent structures extending from the sides of the planar fin. Each turbulent structure defines a longitudinal axis and having a first edge that is parallel to the longitudinal axis and connected to the a planar surface of the fin. Each turbulent structure also includes a second edge opposite the first edged and in free space. The second edge defines a periphery that varies in distance from the first edge along the length of the longitudinal axis. The periphery of each second edge is further shaped such that turbulent flow of a fluid is induced in the flow flowing over the second edge at at least a predefined flow rate.

A heat exchanger includes a body defining a flow channel, and a pin extending across the flow channel, the pin including an at least partially non-cylindrical shape. The pin can be a double helix pin including two spiral branches defining a double helix shape. The two branches can include a uniform winding radius. The two branches include a non-uniform winding radius. The non-uniform winding radius can include a base radius and a midpoint radius, wherein the midpoint radius is smaller than the base radius. The two branches can be joined together by one or more cross-members.