Best Practice Guidelines
For a domestic installation, the following points are 'best practice' and should be taken into consideration for your system:
- Collector area: For a worthwhile contribution to the domestic hot water requirements of most homes, one should consider a collector area of roughly 1m2 (flat plates) or 5 tubes (evacuated tubes) per person living in the household.
- Hot water cylinder: In an unvented pressurised system, the solar thermal collector should be linked into the lower coil of a dual coil cylinder, with the upper coil being linked to the secondary heat source (e.g. gas boiler). The sizing of the cylinder should be closely linked to the area of collectors on the roof, ranging between 25–75 litres per m2 of collector area.
- Orientation & pitch of collector on roof: The optimum orientation is due south, though a collector will work almost as efficiently between SW & SE. If considering an installation on an E/W roof, the collector area should be increased by up to 25% to accommodate losses in efficiency. On a UK roof, the ideal pitch of the collector is around 350 to 900 – conveniently the angle of most of our roofs!