Air Cooling Powered by Façade Integrated Coloured Opaque Solar Thermal Panels

Air conditioning is an important part in building services world-wide in both commercial and residential buildings. With the general attempt to reduce the usage of fossil fuels and increase the usage of green solutions, the market for solar air conditioning is growing rapidly. Solar air conditioning combines solar thermal absorbers to transfer solar radiation into heat with heat-driven cooling technologies. Common heat-driven cooling technologies are absorption and adsorption chillers using heat to produce cold by a thermodynamic cycle. However, solar thermal collectors are currently limited to roof applications, as their black surface with its tubing is not aesthetic. This limits the potential amount of possible heat gain, which could be used for solar air cooling or heating. By using the KlymaaTM opaque coloured solar thermal collectors of SwissINSO, the solar coverage for air cooling and/or heating can be significantly increased, as they are aesthetically integrated into the façade. SwissINSO’s coloured collectors use a cover glass with a thin coating developed by the Solar Energy and Building Physics Laboratory (LESO-PB) of the Ecole Polytechnique Fédérale de Lausanne (EPFL). The coating is a multilayer system deposited by magnetron sputtering on solar float glass. The solar transmittance e of these coatings is high to assure a maximum efficiency of heat absorption by the black absorber behind the coloured cover glass. The absorber can be flat-plate or vacuum tubes, depending on the needs for the air conditioning, as the cover glass is opaque.