A unified approach for designing a photovoltaic solar system for the underground water pumping well-34 at Disi aquifer

•Photovoltaic system for the underground water pumping wells at Disi aquifer was designed.•Solar irradiation values on horizontal and tilted surfaces were identified.•Method of the worst month MWM and peak sun hours PSH method were applied.•Thirty-eight percentage of the total PV panels would not be used beyond the design conditions (December).•Dust accumulation problem were solved by cleaning or as a 5% power loss factor. This paper aims to present a detailed design of a standalone photovoltaic system used to power continuously a submersible water pump from a selected well (Well-34 of a current static water level, SWL=147.3m), out of 55 production wells located at the Disi aquifer, where each of these wells should have a continuously-operating water flow rate of 80l/s (288m3/h) according to the Disi project specifications. Initially, solar irradiation calculations on horizontal and tilted surfaces were carried out to identify the potential of solar energy available in kWh/m2/day in the Disi aquifer. Then, a system design approach based on the worst month of the year (December) was carried out to choose and size the components of photovoltaic system that is required to operate the submersible pump over the 25-year operation period. The system sizing implies defining the number and type of solar panels required to capture the available solar energy, the capacity and number of batteries, inverter rating, cable sizing, charge controller numbers and rating to ensure the maximum reliability of the system. Furthermore, beyond the design conditions of the worst month (December), extra energy can be produced by the PV system during the rest of the year time, which can be used for many purposes. Also, the design process considers the problem of dust accumulation on PV surfaces and this can be dealt with by periodic cleaning.