Analysis of an uncovered photovoltaic/thermal solar system powering a seawater reverse osmosis desalination plant

Abstract

This study aims to quantify how much the uncovered photovoltaic/thermal (PV/T) system is able to assist a small reverse osmosis (RO) desalination unit with a capacity of 1 m3/h of purified water and high salinity seawater (45,000 ppm). For that purpose, a computational tool has been developed, validated, and executed with real meteorological data of Borj-Cedria (Tunisia) site. The validation of both uncovered PV/T and RO separate models has been performed with previous published experiments and different feed flows and locations. When coupling between PV/T and a small-scale seawater RO unit, we found that the use of PV/T not only provides more electricity which reached 21% of the total need for the high pressure pumps of the RO unit (which meet the daily demand for 252 people), but also reduced the electrical energy demand of the desalination unit thanks to the heating of the feed seawater. Economic study showed that the cost of meter cube of purified water produced reached 0.354 US$ including the investment and maintenance cost of the PV/T system. Simulation results also demonstrate that the use of a PV/T can reduce harmful CO2 emissions up to 0.17, 0.70, 1.40, 2.79, and 4.36 ton/year using a caption surface equal to 1.62, 6.48, 12.96, 25.92, and 40.5 m2, respectively. Investigations also showed that the role of the PV/T is still promising for countries like Egypt and Emirates in which the PV/T system can produce about 24.52% and 22.49%, respectively of the energy requirement of the desalination plant.