Experimental investigations on the seasonal performance variations of directly coupled solar photovoltaic water pumping system using centrifugal pump

Optimum sizing and type of photovoltaic array configuration (PVAC) greatly affect the performance of solar photovoltaic water pumping system (SPVWPS). The electric power is decided considering the daily volume of pumped water and the total dynamic head at pumping site. In addition, however, the electric power output of PVAC also depends upon latitude, inclination angle of panel, and seasonal parameters like radiation and temperature, etc. In the present work, experimental investigations have been done to select the optimum PVAC to supply electric power to SPVWPS and effect of seasonal variations on its output. This has been done by investigating the performance of SPVWPS employing a direct current (DC) borehole centrifugal submersible pump along with different PVACs namely PVAC1 (4S × 2P), PVAC2 (5S × 2P), PVAC3 (7S), PVAC4 (8S), PVAC5 (3S × 2P) and PVAC6 (6S) at four pumping heads 2, 3, 4 and 5 bar. 4S × 2P indicates: 2 strings of photovoltaics (PV) module are connected in parallel where each string consists of 4 PV modules connected in series. Similarly, 8S indicates 8 PV modules are connected in series only. The seasonal variations in output of SPVWPS and selection of optimum PVAC have been done by testing in winter and summer seasons in the laboratory under the outdoor conditions of VNIT, Nagpur, India. Through the study, it can be concluded that PVAC2 (5S × 2P) delivered maximum discharge in winter season and PVAC4 (8S) in summer season at all pumping heads.