Solar thermal energy – what is it actually?

Although the name itself says everything you need to know, there is still a lot of confusion surrounding solar thermal energy. Solar thermal energy is often confused with and equated to photovoltaic technology.

This is mainly because both technologies use solar radiation as an energy source. The other reason is that the more common solar thermal flat plate collectors look visually similar to photovoltaic panels.

However, both technologies work fundamentally differently and have completely different applications.

Photovoltaic panels generate electricity through the photovoltaic effect, but with a relatively low efficiency of around 20%. This electrical power can be used, fed into the public power grid, or stored with relatively complex methods.

Solar thermal energy, on the other hand, generates heat from the energy of photons with significantly higher efficiency. For vacuum tube collectors like those from AKOTEC, the efficiency is as high as 60-80%. The heat generated can be used for domestic hot water preparation, heating support, or in large systems for district heating, process heat, and industrial applications.

Due to the much higher efficiency, significant savings on your gas bill can be achieved with minimal surface area. An AKOTEC solar thermal system can easily cover 25% or more of your heating needs.

Additionally, the subsidies available for the installation of a new solar thermal system can cover at least 25% of material and installation costs, which is much higher than the 19% VAT savings currently offered for photovoltaic systems.

Solar thermal can be combined with all common heating systems and retrofitted in almost all homes. For heat pumps, vacuum tubes can make source temperatures more “favorable” in winter, and in summer, conventional heating systems can generally be completely turned off, as solar thermal takes over the hot water preparation. The operating hours of heating systems can be reduced, thus increasing their lifespan.

The overheat-safe heat pipe tubes of AKOTEC collectors also allow for smaller, more affordable expansion vessels, make system protection easier, and reduce temperature stress in the system. With proper pressure maintenance, steam formation and cavitation shocks are avoided. Additionally, the vacuum tubes are very robust. In tests, the tubes withstood being hit by golf ball-sized ice balls at 100 km/h.