Experimental study on the performance of the photovoltaic thermal (PVT) connected in series with flat plate solar collector (ST)

Integrating a photovoltaic thermal system (PVT) with a solar thermal system (ST) allows for the simultaneous achievement of two outcomes: an increase in thermal and electrical efficiency. This work is an experimental study that combines PVT and ST systems together (PVTST) to show how well they work in various weather conditions on four different days in January, February, March, and April. The results showed that the PVTST system raised the output hot water temperature more than the ST system alone. The four testing days recorded temperature differences of approximately (6.15, 6.65, 7.51, and 5.48) °C, respectively. The thermal efficiency of the PVTST system improved by an average of 24.8%, 18.2%, 22.3%, and 19.4%, as compared to the ST system on the four test days, respectively. Similarly, the exergy efficiency showed an average improvement of 7.98%, 7.45%, 7.82%, and 6.97%. The implementation of a PVT system resulted in an average improvement in electrical efficiency of 31.04%, 41.16%, 47.34%, and 11.55% compared to the traditional PV panel during the four selected days, respectively. According to the single room heating simulation results, both the PVTST and ST systems can efficiently heat a single room during the testing days of February, March, and April. However, in January, the ST system had a deficit of approximately 15.9%, whereas the PVTST system had a deficit of around 8.18%. The results indicate that the current PVTST system can meet approximately 61.4%, 79.4%, 77.3%, and 75% of the required hot water temperature on the tested days, respectively.