Image Number 6 for United States Patent #4478210.
A self-cooling solar forced air heating collector module, and method of constructing a plurality of the same in modularized array from standarized components, for a solar heating system. The collector has an inner heating compartment beneath an inner glazing, and an outer heating compartment between the inner glazing and an outer glazing. A forced air inlet duct enters the collector bottom surface and communicates directly only with the outer compartment at a given location longitudinally of the collector. An always-open passage effects air flow communication from the outer to the inner compartment, at one longitudinal end thereof remote from the inlet duct. A sole outlet duct extends through the bottom surface and communicates directly only with said inner compartment in the vicinity of the inlet duct. A black body absorber comprising an air-permeable single layer screen extends within the inner compartment such that the forced air flows along and in the same direction on both sides of the screen. The collector is oriented in operation for solar incidence transverse to the glazings with its lengthwise dimension horizontal and its width dimension tilted at an angle between 10.degree. through 90.degree. from horizontal. Upon cessation of forced air flow via the ducts, whereupon a stagnation condition occurs in the collector, the air trapped therein automatically circulates within the collector and to and from the compartments via the always-open passage in response to solar-incidence-induced convection currents, thereby producing a self-cooling action.