Hybrid solar collector

The paper presents a hybrid solar collector converting the solar energy into both thermal and electric ones. Thus, the solar energy losses are captured to obtain co-generation. The research was conducted at the “Renewable Energy Sources” Laboratory at the Technical University - Sofia, established under the European Tempus Program. The authors present a structure and an approach to study this combined collector, which consist in determining the coefficients of the heat exchange by way of consecutive approximations. The thermal characteristics of the collector, and especially the fluid temperature, the absorber temperature and the cover temperature are determined. The thermal, electrical and total efficiency of the system are also obtained. The results indicate that it is possible to obtain more energy per unit of surface compared to the thermal and the photovoltaic solar collectors separately.