Abstract: A thermoelectric heat transfer system having a thermoelectric device and a heat exchanger with an evaporating surface and a condensing surface. A working fluid is sealed within the heat exchanger. The thermoelectric device includes a thermally conductive hot plate and a thermally conductive cold plate with thermoelectric elements disposed therebetween and the thermoelectric elements are electrically coupled in series and thermally coupled in parallel. The evaporating surface of the heat exchanger is thermally coupled with the hot plate. A fluid flow path to allow working fluid in its vapor phase to flow from the evaporating surface to the condensing surface and working fluid in its liquid phase to flow from the condensing surface to the evaporating surface.

Abstract: An improved radiant heat transfer tube with internal fins is provided. Optimum design characteristics for the number of fins, the height or length of the fins and the twist of the fins is provided to enhance convective and radiant heat transfer from combustion gases inside the tube to the inside surface of the tube. The fin design applies to tubes fabricated from high temperature metal alloys, monolithic ceramics, metal matrix composites or ceramic matrix composites.