Abstract: The present solar heater has partially overlapped solar radiation-absorbing panels of high heat conductivity material inside a housing which has an air inlet and an air outlet in the bottom below different panels. An apertured longitudinal partition in the housing separates the air inlet and outlet. Apertured transverse partitions divide the interior of the housing into three compartments, each containing several overlapping panels which form air passages where they overlap. The panels at the front and back in each compartment are spaced from the front and back walls of the housing to permit air to flow between them.

Abstract: The present forced-air heat exchange system has a solar collector through which air is circulated by a blower to the air inlet of a heat exchanger. The heat exchanger has an air outlet connected to a recirculation duct leading to the air inlet of the blower. A recirculation damper in this duct is open when the temperature of the recirculated air in the system is higher than that of the ambient air outside the system, and it closes when the ambient air temperature is higher. Pressure sensitive draft regulators at the inlet and outlet sides of the recirculation damper remain closed when the damper is open and they open automatically when the damper closes, thereby admitting ambient air into the recirculation duct at the outlet side of the damper and venting the recirculation duct at the inlet side of the damper.

Abstract: This solar heater has a plenum enclosure in the middle of a housing which contains partially overlapping, inclined, blackened aluminum sheets on opposite sides of the plenum enclosure. The interior of the plenum enclosure is divided into an inlet plenum and an outlet plenum, which communicate respectively with the opposite ends of air passages between the sheets. For optimum conversion of solar radiation into heating of the air, each sheet is not more than 0.010 inch thick and the spacing between neighboring sheets where they overlap is not more than 0.025 inch. Air is circulated at a high enough rate to absorb heat from the plates substantially as fast as it is produced in the plates by solar radiation.