Design parameter selection for a distillation system coupled to a solar parabolic trough collector

In this paper a seawater multi-stage flash and a multi-effect distillation system, coupled to a solar parabolic trough collector (PTC) field, are considered. The influence on distilled water production of the main operation and design parameters was studied by thermodynamic analysis. The parameters analyzed define the solar field, the thermal storage and the desalination plant. Firstly, the orientation of the collector axis is determined by the axis azimuth and height. Secondly, the solar field is defined by the distances between rows and columns, the rows azimuth and the number of collectors as the inlet/outlet temperatures of the thermal fluid determine its operation. Finally, the main characteristics of the thermal storage and the desalination plant are the respective capacities and the desalination unit performance ratio and energy supply temperature. The analysis performed is useful not only for selection of the most suitable parameters to increase production, but also for prediction of the water production of a particular system and for water cost calculations. The place selected for this study was the Plataforma Solar de Almeria research center, located in southeastern Spain where a solar multi-effect distillation plant was installed in 1988. Results could be generalized to coastal areas in southern Spain.