Non-imaging optical illumination system

Abstract

A passive solar collector has a reflector or a plurality of reflectors in a tube that is in a partial vacuum and is entirely or partly transparent. An absorber collects light reflected by the reflector or plurality of reflectors and delivers energy from the collected light to a central tube where it heats a substance such as water or other fluid. The absorber is disposed at an angle to the axis of the passive solar collector. The passive solar collector is protected against overheating by one or more devices such as a getter that releases a gas to reduce the vacuum or an opaque shield that is placed so as to cover the reflector in response to an indication of overheating. Reflecting surfaces of the solar collector may be symmetrical or asymmetrical, and they may be smooth or they may have dents, protrusions, or both. The surfaces of the solar collector may be smooth, ridged with smooth curves, or ridged with sharp curves. Collected heat is taken from an absorber to a heat exchanger for use; the absorber may be a double tube carrying a pumped liquid or it may be a heat pipe.