How solar hot water works
With a roof mounted solar collector, the sun’s radiant energy heats the hot water collector. This heat is transferred into the liquid circulating through the hot side tubes. The liquid then travels back to the storage tank. It is circulated inside the pipe work and heat in the liquid is exchanged, increasing the temperature of the water in the tank. Once the heat is exchanged the cooler liquid travels back to the collection panel and process begins again.
A backup electrical or gas booster element can supplement the heating process during winter or periods of low solar irradiation and high hot water demand.
A Heat Pump solar hot water system operates similar to a household air conditioner or refrigerator, in reverse. Air is drawn into the heat pump with a fan and then through an evaporator which contains a special type of refrigerant. This refrigerant, R134a has a boiling point of -21oC, meaning that your heat pump will still function in extremely cold conditions.
The refrigerant, now in gaseous form, is then compressed by the heat pump, which generates an incredible amount of heat. This heat is then transferred into the storage tank, heating your water storage tank for later use. Since the heat has been extracted from the refrigerant, the cool liquid returns to the evaporator to start the process all over again.