Refrigerant charged solar water heating structure and system

A solar water heating system comprising a solar collector structure, a heat exchange structure, said heat exchange structure comprising a closed vessel, tubular means in said vessel, said tubular means having inlet and outlet means extending from said vessel, water storage means, said inlet and outlet means being connected to said water storage means, and pump means connected in one of said inlet and outlet means between said tubular means and said water storage means for circulation of water from said water storage means through said tubular means to heat same and thence back to said water storage means, means for circulating a refrigerant heat transfer medium in gaseous form from the collector structure to the interior of said closed vessel and in liquid form from the closed vessel to the collector structure thereby forming a solar energy system, and a refrigerant heat transfer medium in said solar energy system, said solar collector structure including refrigerant flow structure adapted for the flow of fluid refrigerant therethrough, said last mentioned structure having a lower portion adapted to be flooded with liquid refrigerant and an upper portion contiguous therewith to receive gaseous refrigerant which boils off the liquid refrigerant, electrical control means operative to discontinue operation of the system when the temperature of the water in the storage means reaches a predetermined level and to discontinue operation of this system when the temperature differential in the heat exchange structure is insufficient to cause effective transfer of heat for heating of water, the internal volume of said vessel being greater than the total internal volume of said solar collector structure and said tubular means connecting such vessel and said solar collector structure so that liquid refrigerant may be stored in the vessel during times when operation of the system is discontinued, said solar collector being located to receive sun rays.