What are solar thermal systems made of?
Flat plat collectors are made of metal, glass, insulating and joining materials. Typically copper, steel or aluminium is used for the absorber configuration. The sides and bottom of the collector are usually metal and insulated with mineral wool to minimize heat loss. The glass top is made of special glass to resist facture and maximise transmission of energy. In the future, a variety of materials and combinations of materials including plastics may be used to improve cost benefits ratios, higher temperature ranges and systems performance.
Vacuum tubes collectors are made of a borosilicate glass. Mostly the absorber layer is coated on the inner tube and no metal is required. But there are also tubes with an inner metal fin absorber.
For swimming pool heating, plastic or rubber are used to make low-temperature absorber plates.
The solar collector is usually mounted on the roof and is connected to a circuit containing water with propylene glycol anti-freeze added. The tank is also made of metal, partly stainless steel, partly enamelled steel or copper.