Abstract: A solar collector unit including a corrugated absorber element coated with a reflectively selective coating; a plurality of thin, low mass, low thermal conductivity, thermal isolating elements for supporting the absorber element; and an insulation medium spaced from and generally parallel to the absorber element and disposed on a first side of the absorber element; a reflector surface carried on said insulation medium between said first side and the medium; and an inner transparent insulating sheet spaced from and generally parallel to the absorber element disposed on the second side of the absorber element for transmitting solar radiation to the absorber element and suppressing heat loss.

Abstract: A control circuit for a solar heating system having a solar collector, a heating load and a heat transfer control unit, including a collector valve or damper for controlling the flow of heating fluid to and from the solar collector; a load valve or damper for controlling the flow of heating fluid to and from the heating load; a heating pump for moving the heating fluid; a heat exchanger; and a storage pump for circulating a storage fluid from a storage tank through the heat exchanger, the control circuit including a load sensor for sensing the temperature of the load; a collector sensor for sensing the temperature of the solar collector; a collector switching circuit responsive to an indication from the load sensor that the load temperature is below a preset level and from the collector sensor that the collector temperature is above a predetermined level, to open the dampers and activate the heating pump to move the heating fluid from the load to the collector to be heated and then returned to the load; a sto