'Worst Month’ and ‘Critical Period' Methods for the Sizing of Solar Irrigation Systems – A Comparison

Abstract

Despite the fact that solar photovoltaic (PV) water pumping systems, in particular, irrigation systems have been in use for more than 40 years, there remains a need for their improvement and development. The sizing of such systems is very important in terms of their energy output and hydraulic sustainability. This paper presents and explains an innovative methodology for the sizing of PV irrigation systems, called the Critical Period Method (CPM). CPM includes information about the design of the elements of the solution, the PV system, the pump station and the water reservoir, based on the critical period of operation of each one. The period within which water pumping and water consumption can be balanced is usually at least one day and may be several days, but it is usually no more than five days. A comparison between the most commonly used sizing method, the Worst Month Method (WMM) and the CPM method will be presented. It will be shown that the new method, CPM, could be beneficial for the sizing of PV irrigation systems.