The Solar One House
In September, the University of Delaware celebrated the 40th anniversary of Solar One, the solar-powered demonstration house built by Karl Böer and his team at the Institute for Energy Conversion.
The project was funded in part with a grant from the National Science Foundation and in part by the utility company Delmarva Power and Light.
Completed in July 1973, Solar One looked like one of today’s passive solar designs, with large south-facing windows for winter heat gain, shaded during summer months. But it was much more. The solar collectors integrated into the roof structure (replacing both plywood sheathing and shingles) produced both electric current through cadmium sulfide cells, and warm air through collection boxes behind the CdS modules.
Fans circulated heat during daylight hours, for storage in tanks of chemical salts for space heating at night. And at night, the system stored cool air, which could be circulated, under automatic control, during the heat of the day. Electronic controls also drew and opened the curtains at appropriate times. A battery bank stored electricity for use after dark. The CdS modules provided roughly 80 percent of household electric needs; the house was also grid-tied, one of the first such systems deployed.