Design and Dynamic Modelling of a Hybrid PV-battery System for a House with an RO Water Desalination Unit in Iran

Abstract

Energy crisis and power shortage are major concerns in Iran nowadays, where people experience several blackouts during the day. On the other hand, potable water scarcity is another trend in Iran. In this study, the design and dynamic modelling of a stand-alone hybrid PV-Battery-RO system are discussed for a house in Sinak village, Tehran, Iran. Site characteristics are analyzed in the first part to estimate the house load and deferrable RO load. In the second part, the system has been modelled in HOMER pro software to determine the size of the photovoltaic panels and battery. Moreover, complete electrical details of the system such as system autonomy, unmet load and excess energy have been described. In the third part, dynamic modelling of the small-scale RO unit based on a transfer function is described. The introduced transfer function correctly simulates the system's output flow rate in response to input water pressure variations. Electrical dynamic modelling of the PV- battery system has been designed in MATLAB/Simulink. The results prove that introduced model can simulate the system's behavior in four conditions: normal operating conditions, zero irradiance conditions, maximum irradiance conditions, and net-zero energy conditions. The battery supports the system, and PV arrays power the loads with a fixed and stable voltage and frequency in all the conditions.