This solar water heater is generally used with a water storage tank which has a built-in heat exchanger and backup electrical or gas heating for cloudy days. A working station is used to accommodate for pressure changes and to pump the fluid from the collector to the heat exchanger inside the tank when the solar water heater collector has a warmer temperature than the water in the bottom of your tank. The water is heated when the hot fluid is pumped through the tank. A mixture of water / propylene glycol can be used for the heating fluid to allow for use year-round (which means no freezing problems). An air vent should also be installed the prevent breakage of the lines in case of boiling and to help rid of air during use.