Fossil fuels which are present sources of mankind energy, can’t supply increasing demand of communities for energy. Replacing these sources with sustainable and safe sources of energy is necessary. Renewable energies are permanent, available and clean sources of energy and proper choice for replacing present sources of energy. Solar energy is one of the most widely used kinds of renewable energies which is used today in different ways. Solar energy applications can be factors that affect the performance of hybrid systems. According to the results, increase of inlet temperature by 20 K results in 8% and 15% increase in thermal and electrical efficiencies. Increasing mass flow rate from 0.005 kg/s to 0.1 kg/s, causes 4.3% and 9.7% increase in electrical and thermal efficiencies and 4.9% decrease in outlet temperature of fluid. Therefore mass flow rate should be chosen according to the type of system and priority of thermal and electrical efficiencies or quality of outlet temperature of fluid. Adding one layer of cover on the system results in 19% increase in thermal efficiency and 1.1% decrease in electrical efficiency. Key Words Photovoltaic-thermal systems, Simulation, Thermal efficiency, Mass flow rate
