In solar water heating systems, the sun's energy is used to provide domestic hot water. It is particularly appropriate for existing dwellings where heating system improvements are already being undertaken and a solar collector may be fitted on the roof.
During the summer months a typical solar hot water system can supply 80 and 100 per cent of hot water demand. This will be considerably less in winter.
The overall solar contribution to hot water demand is approximately 50 and 60 per cent annually.
The sun's energy is absorbed by a roof-mounted solar collector. The two main types are:
The operating principals are the same in both cases; the evacuated tube collectors are more sophisticated and generally more efficient than the flat plate collector, but have a higher capital cost.
- Flat plate collectors
- Evacuated tube collectors