Solar Thermal Energy Driven Organic Rankine Cycle Systems for Electricity and Fresh Water Generation

For small to medium scale dispatchable (on demand) power and fresh water generation, solar photovoltaic with battery storage using reverse osmosis and diesel generator based systems can be used. Both options are costly, and in addition, while the former generates highly saline wastewater, the latter results in the production of greenhouse gasses. A more attractive option is, therefore, to use systems driven by solar thermal energy consisting of solar collectors, a power cycle and a thermal energy driven fresh water generation system. However, currently used concentrated solar power technologies (parabolic trough collector, linear Fresnel reflector, solar power tower) use heavy and very expensive glass mirrors and receivers. Recently, a novel polymer foil-based concentrating solar collector system, which avails the advantages of low installation cost, two-axis tracking and low operation and maintenance cost, has been proposed. A techno-economic analysis of a foil-based concentrating solar collector powered organic Rankine cycle based electricity and thermal energy driven fresh water generation system is presented in this paper. Specifically, the objective is to identify which is the more appropriate working fluid for such plant. The results indicate that cyclopentane is the more appropriate organic working fluid, compared to n-pentane, isopentane, hexamethyldisiloxane and toluene, for foil-based solar power plants.