Coupling a small-scale concentrated solar power plant with a single effect thermal desalination system: Analysis of the performance

Abstract

In this paper, the potential of coupling a small-scale non-imaging focusing heliostat CSP plant with a compact single effect thermal desalination plant is presented and an analytical model for assessing the overall performance is described.The main novelty of this work relies on the study of two small-scale prototype units designed and tested by the authors. More precisely, the system consists of 25 hexagonal non-imaging heliostats for a total reflective area of 9.5 m2 with a peak power output of 6 kWt and of a single stage thermal desalination plant for fresh water production of few hundred liters per day.In order to better evaluate the potential of such a coupling, three different locations in the Mediterranean area have been considered: Palma de Mallorca, Pantelleria and Crendi.The simulation analysis proved interesting results. Compared to electrically driven desalination plant, the performance of the proposed plant is only slightly affected by the salt content of the treated water. In terms of fresh water production, the yearly fresh water production in Crendi is about 60% higher than in Pantelleria because of the higher DNI throughout the year. On the contrary, the maximum daily fresh water production differs to a smaller extent: it reaches a peak of about 70.5 L/day in Pantelleria and 75.0 L/day in Crendi whilst it is always <60 L in Palma.Despite further improvements are needed to reduce the cost of the fresh water produced by similar small-scale CSP desalination plant to overcome the market uptake, the results of the analysis have shown that such a coupling could have a very interesting potential especially for small-scale applications in rural and remote areas where the fresh water demand ranges between 30 L and 60 L per day.