Solar water heating system and heat exchanger therefor

Claim 1

A solar water heating system comprising a water storage tank including cold water inlet means and heated water outlet means and comprising a water utilization system, a solar collecting unit having cold liquid inlet means and heated liquid outlet means and comprising a heating liquid system, an independent heat exchanger disposed between said water utilization system and said heating liquid system, and means associated with said collector unit and said heat exchanger for draining the liquid from said solar collector and into said heat exchanger under certain predetermined temperature conditions, said independent heat exchanger comprises an outer tank having first inlet means of a predetermined size to accommodate a vent pipe and liquid flow for receiving heated liquid from said solar collecting unit and first outlet means for transferring cooled liquid to said solar collecting unit, a series of heat exchanger coils inside of said outer tank and having second inlet and second outlet means connected, respectively, to the cold water portion and the hot water portion of said water storage tank, said second outlet means of said heat exchanger being adjacent the first inlet means of said outer tank, and a closed tank disposed interiorly of said series of heat exchanger coils and having a third outlet connected to said first outlet means, said inner tank having a volume sufficient to provide an air space in addition to the volume of liquid from the solar collection unit and having at least one opening therethrough communicating with the space between the inner and outer tanks adjacent said third outlet, and a gas vent pipe extending from the interior of said second tank through said first inlet means.