The solar collector The solar collector is often placed on the roof, but can just as well be situated on a framework placed on the ground. The total area of solar collectors needed for a single family system varies from four to six square meters, depending on consumption, orientation and efficiency of the collectors and the place on the globe. Normally, the top is covered with single or double glazing, sometimes with transparant plastic. The storage tank has to be very well insulated too. The storage tank contains about 50 liter of water for every square meter of solar collector area.
Cold water enters the tank at the bottom, and heated by the heat exchanger.
Since hot water is lighter than cold water, it will rise to the top of the tank. From the top of the tank there are pipes to the shower and water taps. It is possible to put a second heat exchanger in the tank, which takes its heat from a conventional wood, oil, or gas stove. This heat exchanger will only work if the solar collectors can not provide enough hot water, mostly on very cloudy days. This second heat exchanger can also be an electrical heating element.