Modeling of a combined photovoltaic/thermal energy system

The utilization of solar energy can be made by photovoltaic (PV) cells to generate electric power directly and solar thermal (T) panels can be applied to generate heat power. When the utilization of the solar energy is necessary to generate electric power, the option of using T panels in combination with some heat/electric power conversion technology can be viable solution. The power generated by utilizing the solar energy absorbed by a given area of solar panel can be increased if the two technologies, PV and T cells, are combined in such a way that the resulting unit will be capable of cogeneration of heat and electric power. A is system proposed for converting the energy, obtained from solar radiation, into electric energy. The combined photovoltaic/thermal panels are connected to a heat/electric energy conversion system converts heat energy into mechanical energy that is converted further into electric energy by a turbine-generator-converter unit connected to the utility mains or a group of loads. The development and design of the system is made by extensive use of modeling and simulation techniques. In the paper a part of the simulation studies, carried out to determine the energy balance in the electric energy conversion section of the system, assuming standalone operation is presented. The energy balance in the long run is basically determined by the energy supplied by the photovoltaic cells and the energy consumed by the load. Simulation results are presented that show the operation of the PV part of the system in a longer period of time.