A heat exchanger (4) has fluid flow channels (6) with at least one heat exchanging surface (10) which has an undulating surface section for which the surface profile varies along a predetermined direction such that at a first edge (E1) the surface profile follows a first transverse wave (20), at a second edge (E)2 the surface profile follows a second transverse wave (22) and at an intermediate point I between the edges the surface profile follows a third transverse wave (24). The third transverse wave (24) has a different phase, frequency or amplitude to the first and second transverse waves so that chevron-shaped ridges and valleys are formed. This improves the mixing of fluid passing through the channel and hence the heat exchange efficiency.

An HVAC heat exchanger with an array of tubes including one or more dead tubes is provided. In one embodiment, the heat exchanger is a microchannel heat exchanger operable to exchange heat with air in an HVAC system via refrigerant passing through the microchannel heat exchanger. The microchannel heat exchanger includes an array of flat tubes arranged between a first manifold and a second manifold. The array of flat tubes includes multiple tubes coupled in fluid communication with the first manifold and the second manifold to convey refrigerant between the first manifold and the second manifold through microchannels of the multiple tubes. The array of flat tubes also includes one or more dead tubes that do not convey refrigerant between the first manifold and the second manifold. Additional systems, devices, and methods are also disclosed.

A heat exchange tube, a heat exchanger, and a manufacturing method for the heat exchange tube are provided. The heat exchange tube includes a tube wall and an outer fin, the tube wall is folded into a tube body, the tube body is provided with an inner fin therein, and the inner fin divides an inner chamber of the tube body into a plurality of flow channels. The outer fin is arranged outside the tube body. The outer fin is folded from a same plate with at least one of the tube wall and the inner fin.

A heat exchanger (4) has fluid flow channels (6) with at least one heat exchanging surface (10) which has an undulating surface section for which the surface profile varies along a predetermined direction such that at a first edge (E1) the surface profile follows a first transverse wave (20), at a second edge (E)2 the surface profile follows a second transverse wave (22) and at an intermediate point I between the edges the surface profile follows a third transverse wave (24). The third transverse wave (24) has a different phase, frequency or amplitude to the first and second transverse waves so that chevron-shaped ridges and valleys are formed. This improves the mixing of fluid passing through the channel and hence the heat exchange efficiency.

An inward gas/liquid distribution structure used in microchannel heat exchangers is disclosed. The inward gas/liquid distribution structure can help optimizing refrigerant distribution for a microchannel heat exchanger with long distribution pipe or a microchannel heat exchanger having significant wind field differences. The inward gas/liquid distribution structure includes an inlet header component. The inlet header component has n inlets that are configured to allow gas/liquid to enter the inlet header component, and n is an integer that is greater than or equal to 2. The inward gas/liquid distribution structure also includes m distribution components. The m distribution components are located in the inlet header component and connected to the n inlets, respectively. In an example, the number m equals to the number n.

A heat exchange tube, a heat exchanger, and a manufacturing method for the heat exchange tube are provided. The heat exchange tube includes a tube wall and an outer fin, the tube wall is folded into a tube body, the tube body is provided with an inner fin therein, and the inner fin divides an inner chamber of the tube body into a plurality of flow channels. The outer fin is arranged outside the tube body. The outer fin is folded from a same plate with at least one of the tube wall and the inner fin.

A heat transfer apparatus includes a tubular wall defining a lumen and multiple pipe elements arranged about a circumference of the tubular wall and passing through the tubular wall. The lumen is configured such that fluid flows through the lumen of the heat transfer apparatus. Each pipe element of the multiple pipe elements includes an interior portion located within the lumen of the tubular wall and configured to absorb heat from the fluid that flows through the lumen and includes an exterior portion located exterior to the tubular wall and configured to release at least a portion of the heat absorbed at the interior portion to an ambient environment.

A cooling apparatus is disclosed. The cooling apparatus comprises a housing, a first liquid and a second liquid located within the housing. The first liquid has a higher density and lower boiling point than the second liquid. The cooling apparatus further comprises a heat exchanging apparatus to transfer heat to the first liquid to evaporate the first liquid to form a first liquid vapour. The cooling apparatus also comprises a plurality of independent energy dissipating members that extend through the housing. These members move in response to a fluid flow created by the interaction of the first liquid vapour and the second liquid and transfer heat to a volume external to the housing. The cooling apparatus can cool a body whilst drawing minimal or even no electrical power. As such the cooling apparatus is environmentally friendly and cheaper to operate.

The present invention relates generally to electric power and process heat generation using a modular, compact, transportable, hardened nuclear generator rapidly deployable and retrievable, comprising power conversion and electric generation equipment fully integrated within a single pressure vessel housing a nuclear core. The resulting transportable nuclear generator does not require costly site-preparation, and can be transported fully operational. The transportable nuclear generator requires an emergency evacuation area substantially reduced with respect to other nuclear generators as it may be configured for operation with a melt-proof conductive ceramic core which allows decay heat removal even under total loss of coolant scenarios.

A heat exchanger for use in high pressure environments, such as in a gas turbine engine, includes an outer casing, a tubular element within the outer casing and an inner sleeve within the tubular element. The tubular element has an outer surface and an inner surface. The outer casing and outer surface of the tubular element define a first annular passage through which a first fluid flow path extends. The inner sleeve and inner surface of the tubular element define a second annular passage through which a second fluid flow path extends. The first annular passage is sealed against the outer surface of the tubular element and the second annular passage is sealed within the inner surface of the tubular element.