International Journal of Engineering and Technology

Solar energy is one of the most promising renewable sources of energy for present needs. Solar Photovoltaic Thermal (PV/T) system is a hybrid system to produce both thermal and electrical energy. This paper attempts to investigate the thermal and electrical performance of a solar photovoltaic thermal (PV/T) air collector with single and multi-ducts. The performance of the 50 Wp PV module with and without cooling is analysed. The thermal model is used to estimates the air outlet temperature, cell temperature and back surface temperature. The outcome of the model is verified by the experimental results. The electrical and thermal outputs are suitably combined to get the overall thermal efficiency of a PV/T air collector. The electrical efficiency is found to vary from 10.2 to 11.5%, efficiency being low at high temperature. The air cooling of the module increases the minimum and average efficiency. The maximum and average values of overall thermal efficiency are found to be 49.3% and 43.2% in the single duct case and 39.6% and 36.74% in the multi-duct case, when velocity of air is maintained at 3 m/s. When multi-duct is used, the temperature difference between the cooled and uncooled portion of the module is found to vary from 2o C to 5o C. This temperature difference can be reduced by maintaining the higher flow velocity. The non-uniform temperature profile created by the multi-duct cooling system reduces the module electrical efficiency by 0.4%, compare to single duct cooling. It indicates that the distribution of any coolant at the base for cooling must be distributed as uniformly as possible. Any lack of uniformity in distribution may lead to considerable loss of energy. Thus, proper care must be taken to distribute the coolant by providing proper baffles so as to ensure uniform cooling to obtain best possible performance.