Development of multivalent PV-thermal collectors for cooling, heating and generation of electricity

Growth of cities and rising occupant comfort expectations has led to an increasing cooling demand of buildings. The use of solar energy for the production of electricity with photovoltaic modules and hot water with solar collectors is a common application. Operating the PV-T collectors at night is the possibility given to cover the cooling demand with a renewable energy source; radiative cooling. This paper focuses on the potential analysis of PV-T collectors for heating, cooling and electricity production for 6 different climate conditions. First the state of the art, four different PV-T technologies and two examples for building integration are presented. This new prototypes of PV-T collectors with different joining methodologies between the absorber and the PV module have been developed and tested at an outdoor test stand under dynamic conditions. Measurements of these four new collector types are shown and compared with a TRNSYS PV-T collector model. Finally a potential analysis for heating, cooling and electricity production for one of the developed PV-T collector was carried out under different climatic conditions. The simulation results showed that this PV-T collector has the highest cooling potential in cold and moderate climate zones where cooling is needed only temporarily. In hot and humid climates where cooling is needed over the whole year, the cooling potential of the PV-T collector for radiative cooling is less. The increase of electricity production by cooling the PV cells varies between 0,1 and 5,8 %, depending on the inlet temperature and the weather conditions