A wind-powered seawater reverse-osmosis system without batteries

The development of small-scale stand-alone desalination systems is important to communities on islands and in isolated inland areas. In such places, electricity supplies are often expensive and unreliable, while the wind resource is abundant. The system presented here comprises a 2.2 kW wind turbine generator powering a variable-flow Reverse osmosis (RO) desalination unit. It is highly efficient, rugged, built with off-the-shelf components and suitable for use in remote areas. Operation at variable-flow allows the uncertainty and variability of the wind to be accommodated without need of energy storage. Batteries, which are common in stand-alone systems, are avoided and water production is dependent on the instantaneous wind speed. A model-based control strategy is used to independently maximize both the energy extracted from the wind and the water output of the RO unit. A computer model of the system has been developed based on component models, identified through laboratory testing. Performance predictions are presented and discussed.