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| A hot water storage tank where one of the heat sources is solar heating A, that is sent into the hot water storage tank via a smaller pump B (circle with triangle) and the heat exchanger spiral in the hot water storage tank. The other spiral C can be used for a e.g. oil-fired boiler or a wood burner. At D the hot water gets out and domestic cold water is sent back at the bottom at E. (Photo credit: Wikipedia) |
The most common commercial collectors consist of copper fins that are soldered or welded to copper pipes. In operation, the sun heats the fins, which in turn transfer their heat to the copper pipes and then to the water flowing through the pipes.
The collector could be made of a simple glass topped insulated box with a flat solar absorber made of sheet metal attached to copper pipes and painted black, or a set of metal tubes surrounded by an evacuated (near vacuum) glass cylinder. In industrial cases a parabolic mirror can concentrate sunlight on the tube. Heat is stored in a hot water storage tank.
But, the design, does have some drawbacks from a build-it-yourself viewpoint: 1) the materials have become very expensive, 2) soldering or welding the copper pipes to the fins is time consuming and not a common DIY skill.
This is a simple design that can be build using common recycled material.
