Solar thermal

Evacuated tube collectors located on roof of school alongside pV panels)
Evacuated tube collectors located on roof of school alongside pV panels

Solar water heating systems use heat from the sun to heat water which can be used for hot water or in some cases to contribute towards heating the building. The system involves a solar collector, a heat transfer system, and hot water cylinders for storage.

Solar collectors are usually fitted to the roof where they collect heat from the sun. The transfer system then uses this to heat water. A hot water cylinder stores the hot water that is heated during the day and supplies it for use when needed.

Two types of system are available:

  • Flat plate;
  • Evacuate tube.

Evacuated tubes systems are generally more efficient than flat plates as they lose less heat due to the vacuum. However, flat plate systems are less prone to vandalism as they are more robust.

Orientation and shading can have an impact on energy output. However, solar thermal collectors can be fitted to roofs up to 90˚ of a south facing orientation.

Link to short examples

What should I do?

Ensure that orientation and overshadowing issues are considered to maximise performance.

WLGA - CLILC Llywodraeth Cynulliad Cymru / Welsh Assembly Government