Unitary heat exchangers having integrally-formed compliant heat exchanger tubes and heat exchange systems including the same are provided. The unitary heat exchanger comprises an inlet plenum and an outlet plenum and a plurality of integrally-formed compliant heat exchanger tubes. The plurality of integrally-formed compliant heat exchanger tubes extend between and are integral with the inlet and outlet plenums to define a heat exchanger first flow passage. Each integrally-formed compliant heat exchanger tube comprises a tubular member and a plurality of integral heat transfer fins extend radially outwardly from at least one portion of the tubular member. The tubular member has a proximal tube end and a distal tube end and comprises a tubular wall having an outer wall surface and an inner wall surface.

Unitary heat exchangers having integrally-formed compliant heat exchanger tubes and heat exchange systems including the same are provided. The unitary heat exchanger comprises an inlet plenum and an outlet plenum and a plurality of integrally-formed compliant heat exchanger tubes. The plurality of integrally-formed compliant heat exchanger tubes extend between and are integral with the inlet and outlet plenums to define a heat exchanger first flow passage. Each integrally-formed compliant heat exchanger tube comprises a tubular member and a plurality of integral heat transfer fins extend radially outwardly from at least one portion of the tubular member. The tubular member has a proximal tube end and a distal tube end and comprises a tubular wall having an outer wall surface and an inner wall surface.

A kinetic heat sink has a stationary member mountable to a heat-generating component, and a rotatable structure coupled with the stationary member across a gap. The stationary member has a heat spreader formed from a plurality of layers that includes a given layer having a radial heat spreading element and an axial heat spreading element. The radial heat spreading element has a first radial thermal conductance. The axial heat spreading element has a second radial thermal conductance. The first radial thermal conductance is greater than the second radial thermal conductance. The axial heat spreading element has a first axial thermal conductance. The radial heat spreading element has a second axial thermal conductance. The first axial thermal conductance is greater than the second effective axial thermal conductance. At least a portion of the axial heat spreading element is radially inward of at least a portion of the radial heat spreading element.

A kinetic heat sink has a stationary member mountable to a heat-generating component, and a rotatable structure coupled with the stationary member across a gap. The stationary member has a heat spreader formed from a plurality of layers that includes a given layer having a radial heat spreading element and an axial heat spreading element. The radial heat spreading element has a first radial thermal conductance. The axial heat spreading element has a second radial thermal conductance. The first radial thermal conductance is greater than the second radial thermal conductance. The axial heat spreading element has a first axial thermal conductance. The radial heat spreading element has a second axial thermal conductance. The first axial thermal conductance is greater than the second effective axial thermal conductance. At least a portion of the axial heat spreading element is radially inward of at least a portion of the radial heat spreading element.

A rotary exhaust heat recovery apparatus may include an exhaust gas pipe including a bypass path into which a high-temperature exhaust gas is introduced and bypassed and an extension part extending from a side of the bypass path in a semi-cylindrical shape to allow the exhaust gas to pass and a semi-cylindrical heat exchanger rotatably accommodated within the exhaust gas pipe, allowing heat exchange to be performed between the high-temperature exhaust gas supplied from the bypass path and a low-temperature coolant introduced through a coolant inlet, in which a side surface of the heat exchanger includes a diameter surface formed as a flat surface and an arc surface formed as a curved surface, and the diameter surface of the heat exchanger has a surface with a rotation axis of the heat exchanger as a reference thereof which is closed and another surface provided with exhaust gas inlets.

A rotary exhaust heat recovery apparatus may include an exhaust gas pipe including a bypass path into which a high-temperature exhaust gas is introduced and bypassed and an extension part extending from a side of the bypass path in a semi-cylindrical shape to allow the exhaust gas to pass and a semi-cylindrical heat exchanger rotatably accommodated within the exhaust gas pipe, allowing heat exchange to be performed between the high-temperature exhaust gas supplied from the bypass path and a low-temperature coolant introduced through a coolant inlet, in which a side surface of the heat exchanger includes a diameter surface formed as a flat surface and an arc surface formed as a curved surface, and the diameter surface of the heat exchanger has a surface with a rotation axis of the heat exchanger as a reference thereof which is closed and another surface provided with exhaust gas inlets.

A heat rejection system that employs temperature sensitive shape memory materials to control the heat rejection capacity of a vehicle to maintain a safe vehicle temperature. The technology provides for a wide range of heat rejection rates by varying the shape and thus effective properties of the heat rejection system in response to temperature. When employed as a radiator for crewed spacecraft thermal control this permits the use of higher freezing point, non-toxic thermal working fluids in single-loop thermal control systems for crewed vehicles in space and other extraterrestrial environments.

A heat rejection system that employs temperature sensitive shape memory materials to control the heat rejection capacity of a vehicle to maintain a safe vehicle temperature. The technology provides for a wide range of heat rejection rates by varying the shape and thus effective properties of the heat rejection system in response to temperature. When employed as a radiator for crewed spacecraft thermal control this permits the use of higher freezing point, non-toxic thermal working fluids in single-loop thermal control systems for crewed vehicles in space and other extraterrestrial environments.

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.

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.