Solar Collectors
Solar collectors are the key component of solar-heating systems. There are several types of solar collectors:
- Evacuated tube collectors
- Flat plate collectors
- Evacuated tube collectors
A vacuum tube collector (Fig. 1) consists of a group of single vacuum tubes linked together to one collector. Built into each tube is a coated absorber made of copper or glass. The vacuum in the glass tubes ensures optimum heat insulation. This allows the collector to make use of diffused radiation too. Reflector s on the backside of the tubes can increase the absorption of solar radiation even further.
Flat plate collectors
The main component of a flat collector (Fig. 3) is a coated copper absorber. It gives high absorption of solar radiation and low emission of thermal radiation. Embedded into the absorber is a copper pipe through which the solar liquid flows. The absorber is surrounded by a highly insulated collector housing made of alloy to minimise heat loss. The cover is made from anti-reflective solar glass.