Energy Management and Supervisory Control of Solar-Powered RO Desalination Systems

Abstract

The integration of photovoltaic (PV) energy with reverse osmosis (RO) desalination has emerged as a promising approach to addressing freshwater scarcity while reducing dependence on fossil fuels. However, the intermittent nature of solar energy and the dynamic operating characteristics of RO systems create significant challenges for maintaining stable operation, particularly in critical-load applications such as healthcare dialysis centers where continuous operation and strict water quality are non-negotiable. This paper presents an intelligent supervisory control framework for PV-powered RO desalination systems that coordinates energy management, operational modes, and process control within a unified architecture. Unlike conventional approaches that treat the RO unit as a passive electrical load, the proposed framework models it as a dynamic electrical and hydraulic process requiring continuous coordination between PV generation, battery energy storage, and desalination operation. The supervisory controller employs a rule-based logic algorithm to seamlessly regulate operating modes according to real-time PV availability and battery state-of-charge. To ensure practical relevance, the control logic is tailored to a representative critical application: a 20-chair dialysis center requiring a continuous high-quality water supply of 1800 L/h (conductivity < 7 µS/cm). Developed within a MATLAB/Simulink environment, the control logic is structured for straightforward implementation on industrial programmable logic controllers (PLCs). The framework emphasizes operational stability, adaptive load management, and implementation readiness over purely theoretical control design, establishing a practical and scalable foundation for subsequent numerical simulations, experimental validation, and field deployment.