Abstract: A solar collector of the non-tracking fluid circulating type which is formed of light weight materials and comprises a frame supporting fluid circulating tubes having a light absorber disposed axially therein and lined with retroreflective cube-corners. The tubes are placed in semicircular reflectors and enclosed by a transparent barrier sheet and cover having light anti-reflective coatings.

Abstract: The solar heating system component combines a surge tank for a closed solar heat collecting system along with heat exchange means for transferring heat from the primary fluid in the solar heat collecting system to secondary fluid flowing in a secondary circuit which is used for a purpose such as to supply warm water, space heating or cooling, and the like. A control device is provided to cause slower movement of the primary fluid in heat exchange with the secondary fluid when the temperature differential therebetween is low and to increase the rate of said flow when the temperature differential increases.