Abstract: A solar liquid-to-liquid heat exchanger, method of making the same, and hot water heating apparatus employing same are provided wherein such heat exchanger is comprised of a first tubular member made of a heat conductive tube material and having a plurality of turns, a second tubular member made of a heat conductive tube material and having a plurality of turns which correspond to and are fixed against the turns of the first member to provide a strong mechanical and thermal connection between immediately adjacent faces of associated member turns. The fixing of the turns of the members and utilization of the heat exchanger in a hot water heating apparatus with flow of a solar fluid used in such apparatus in one direction through the first tubular member and water to be heated through the second tubular member in counterflow to the one direction assures optimum transfer of heat from the solar fluid to the water to be heated.

Abstract: A solar collector is provided comprising a cover assembly which employs a flexible polymeric cover sheet and means for stretching the cover sheet and maintaining it taut under various ambient temperature conditions, a simple and economical peripheral supporting structure, and support means for a solar heat exchanger of the solar collector which supports such heat exchanger in a high strength manner yet in thermally insulated relation.

Abstract: Apparatus for heating and maintaining the temperature of water in a hot water tank of a solar hot water system and method of making same are provided wherein such apparatus comprises a thermally insulating container disposed around and in spaced relation from the tank with the container having a bottom portion defining a sump for a heat transfer liquid employed in the system and a device for maintaining the level of such liquid in the sump beneath the tank during normal system operation to thereby assure maintenance of an air space substantially completely around the tank with the air space cooperating with the insulating container to assure the temperature of water in the tank is maintained with minimum loss; and, the apparatus may also employ a pressure sensitive shut-off device in the cold water supply to the tank which cooperates with the air space to assure operation of the system with substantially no likelihood of contamination of the cold water supply.