An Experimental Investigation of a Concentrating PVT Systems

Solar Photovoltaic (PV) systems harness the solar energy from the sun and converts it into electrical energy. The electrical efficiency of a PV system depends on the type of cells, and the working temperature of the system. The efficiency of a PV module decreases as its temperature increases due to incoming solar radiation. Even with the decreasing cost of the PV modules, the efficiency is still low due to the above mentioned factors (ideal conversion efficiency is about 15%) and most of the radiation reaching to the PV modules is wasted as heat. Therefore, there is a need to remove or better still utilize this waste energy. The Photovoltaic- thermal system (PV/T) is a hybrid system that produces thermal energy as well as electrical energy. This thesis experimentally investigates the use of solar concentrated photovoltaic-thermal system (CPV/T) to boost the overall productivity of the solar PV module. In CPV systems mirrors or lenses are used to concentrate sunlight onto solar cells. High-efficiency solar cells are used in CPV systems where concentration ratios are high but conventional solar cells can be used at low concentration ratios (i.e., less than 10). The studied CPV/T system uses mirrors to intensify the solar radiation on the PV module of about 3 times. The performance of the CPV/T collector was analyzed and compared to that of the reference PV module working under the same weather conditions of the Northern Cyprus in the month of June. The CPV/T system was established by attaching a set of 4 mirrors to the module frame and a glass duct mounted on the top of the module for cooling purpose. With Water used as the coolant and heat carrier. The inlet temperature of the coolant was varied between 14 oC and the ambient temperature (i.e., 14°C, 18°C, 22°C and ambient temperature). In this experimental work, it was found that the CPV/T collector performed better using an inlet cooling water temperature of 14°C. The maximum electrical power output from the CPV/T system was 49.06 W yielding a 3.3 times the rated power of the PV ( 15 W at STC), and its maximum thermal output was 920 Wh/m2. Keywords: Photovoltaic, CPV/T collector, Electrical power, Thermal energy.