Evacuated Tube Solar Thermal System

A solar thermal system consists of a collector panel which absorbs the energy from the sun and transfers it to a working fluid (usually water). This is pumped around a loop which transfers the heat collected to a hot water or buffer tank, either directly or through a heat exchanger. The pump is often powered by a small PV panel, which means that no external electricity is required. Finally, there is a control system which determines when to pump the fluid around, depending on the level of heat being provided by the sun at the time. Evacuated tube collectors consist of a series of vacuum tubes which collect the heat onto a fin and tube arrangement. They are more efficient and therefore less area is required. They also heat the water to a higher temperature and remain effective on cloudy days.