Abstract: The heat of solar radiation is collected through a thin receptor panel directly into liquid held against and flowable upwardly along the panel in shallow channels extending between upper and lower plenum spaces in a receptor chamber which is inclined across the path of the sunlight and connected in a flow circuit kept completely filled with the liquid under a limited constant hydrostatic pressure. The flow circuit extends from the upper plenum space to a heat exchange zone and then back into the lower plenum space. The receptor chamber is formed by two flexible plastic panels which are sealed together peripherially and also along closely spaced longitudinal seams to provide the channels and plenum spaces.

Abstract: A heat exchanger includes a hollow shell that defines an elongate shell space for circulation of a first fluid therethrough, and a plurality of elongate tubes spaced apart inside the shell to conduct a second fluid therethrough in heat exchange relation with the first fluid in the shell space. The heat exchanger further includes an improved assembly for coupling an end of the shell with adjacent ends of the tubes and for conducting the respective fluids separately into and from the tubes and into and from the elongate shell space without leakage. This assembly comprises a socket member having forward and backward socket portions and an annular shoulder portion protruding inwardly between them. The forward portion is connected in fluid-tight relation to an end of the shell and has a passageway extending through it for conducting the first fluid into or from the elongate shell space.