The effects of an operating head on the performance of photovoltaic water pumping systems: an experimental investigation

The possibility of improving the performance of a photovoltaic (PV) water pumping system using two different arrangements and four different heads was investigated. In both arrangements, the performance of the PV water pumping system was calculated under different operating heads and the results were compared with each other. Experimental results show that when the operating head is fixed, the calculated array power should not be more than the power of the motor pump at maximum speed, because the array and system efficiencies decrease and the remaining array power is not utilized. However, in this case, in spite of lower efficiencies more water is pumped during the day. Furthermore, the results show that two criteria should be met when designing PV water pumping systems: first, the maximum power corresponding to the selected head, and second, the consumer requirements. Satisfying both requirements helps to reduce the installation cost in PV water pumping systems.