Abstract: A mass produced, easily assembled heat exchanger for use in cooling a cabinet or other enclosure by convection over both ends of fins which penetrate the wall of the enclosure. The configuration of the preferred embodiment has offset fins alternating in and out of the enclosure with the overlap at the enclosure wall and each fin acting as a spacer for the adjacent ones. An alternate embodiment uses a "U" shaped spacer to wrap around the overlapping edge of each fin, thus increasing the air flow space between fins without increasing the thickness of fins.

Abstract: A self-pumping solar liquid heating system which includes two solar collectors, a high temperature collector for generating vapor which expands and pumps fluid through the system, and a separate collector for collection of heat of utilization. A heat pipe transfers the heat from the high temperature collector to a vapor generator pump which moves the liquid in series through the second collector, a heat load and a liquid reservoir. Mechanical temperature controls are used to regulate the temperature of the heat load so no electrical power is required for the system.