TECHNICAL COMPARISON OF DIFFERENT SOLAR-ASSISTED HEAT SUPPLY SYSTEMS FOR A MULTI-EFFECT SEAWATER DISTILLATION UNIT

摘要

Seawater desalination is a promising option for fresh water supply in arid coastal regions faced with water scarcity. Solar desalination has significant potential for application where fresh water shortage coincides with good solar radiation and availability of seawater. In the context of an ambitious R&D project to lower the current cost of solar desalination, a comparative assessment of three different configurations for supplying solar thermal energy to a multi-effect distillation plant for seawater desalination has been performed for a solar fraction of 50%, using natural gas as a backup energy source and a fresh water production capacity of 53 m3/day. All three configurations were demonstrated to be technically feasible and only socio-economic (capital costs, operation and maintenance costs, easy scaleup) and geographical considerations (installation in remote areas, skilled workers availability) would influence choice. Coupling of heat recovery devices such as an absorption heat pump looks to be a promising way to increase the overall thermal efficiency of the desalination plant.