Abstract: A flat plate solar collector system embodying a plurality of individual conventional solar collector panels in which the frames of said panels are provided with notched portions or recesses for the reception of union type pipe couplings joining the headers of adjacent panels to permit the several panels to be assembled in butted side-by-side or precisely contiguous relation. Additionally, cover plates are provided for the recesses to present a unitary appearance to the assembly.

Abstract: An air conditioning system comprising a heat exchanger using the conduction principle to impart a portion of the heating or cooling from the air exhausted from a building or facility to a make-up air supply and a heat pump which provides supplemental heating or cooling for the make-up air supply to bring it to the desired temperature for use in the building or facility.

Abstract: A heat exchanger comprising a novel design, construction and arrangement of readily formable separately sealed channels for the transmission therethrough of fluids to impart heat through conduction and convection from a heated fluid to a fluid to be heated and to be used for heating a work area of a building and the like.