Desalination augmented by energy storage

Abstract

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.

Desalination has become imperative as a drinking water source for many parts of the world. Due to the large quantities of thermal energy and high quality electricity requirements for water purification, the desalination industry depends on waste heat and renewable energy sources such as solar collectors, photovoltaic arrays, geothermal and wind and tidal energy sources. Due to the mismatch between the source supply and the demand and intermittent nature of these natural energy sources, energy storage is a must for reliable and continuous operation of these facilities. Thermal energy storage requires a suitable medium for storage and circulation while the photovoltaic/wind generated electricity needs to be stored in batteries for later use. Desalination technologies that utilize thermal energy and thus require storage for uninterrupted process operation are multi-effect evaporation (MED), low temperature desalination (LTD) and humidification-dehumidification (HD) and membrane distillation (MD). Energy accumulation, storage and supply are the key elements of thermal energy storage concept which result in better economics, resource management and lower environmental emissions of a variable energy source powered desalination system, for instance, solar energy. Similarly, the battery storage is essential to store electrical energy for electrodialysis (ED), reverse osmosis (RO) and mechanical vapor compression (MVC) technologies. This research-review paper discusses current energy storage options for different desalination technologies using various renewable energy and waste heat sources with focus on thermal energy storage and battery energy storage systems. Principles of energy storage are discussed for the first time with details on design and sizing and desalination process applications.