Solar thermal systems use panels or tubes, collectors, to capture thermal energy from the sun which is often used for domestic hot water but also has a range of other applications. There are primarily two types of solar thermal panels available on the UK market: flat-plate collectors and concentrating collectors. Flat-plate. The evacuated tube solar thermal system is one of the most popular solar thermal systems in operation. An evacuated solar system is the most efficientand a common means of solar thermal energy generation. Flat plate solar thermal systemsare another common type of solar collector which have been in use since the 1950s. The main components of a flat plate panel are a dark coloured flat. Solar air heaters are mostly used for space heating and can be both glazed and un-glazed. They are among the most efficient and economicalsolar thermal technologies available and. Thermodynamic solar panelsare a new development in solar thermal technology. They are closely related to air source heat pumps in their design but are deployed on the roof or walls like regular solar thermal panels and do not have to.