Numerical study on the effect of solar radiation intensity on the fresh water productivity of solar still equipped with Thermoelectric Cooling System (TEC) for hot and dry areas of Semnan

Abstract

The fresh water crisis is one of the most important issues in the world and as a solution one of the most important methods of freshwater production is the evaporation of saline water by using of solar stills. Semnan province is one of the largest provinces in Iran. The province covers an area of 97,491 km 2 , which is 5.9% of the total area of the country. This province is the seventh largest province in Iran and is located almost in the central desert region of Iran. Due to its location on the solar belt, the desert areas of Semnan province are prone to the installation of solar cells, and according to the statistics of the General Meteorological Department of Semnan, this province has 325 sunny days in 365 days of the year. Therefore, this area is a great location for using clean solar energy. In this research, using the numerical method, the effect of the presence of the Thermoelectric Cooling System (TEC) on the performance of solar still, intensity and direction of solar radiation has been investigated to check their effect on the rate of freshwater production. The simulations were performed for Semnan city condition with the method of humid air in a three-dimensional, steady and laminar regime by solving the equations of continuity, Navier-Stokes, and water vapor concentration. The results show that there is a direct relationship between radiation intensity and water production rate and increasing radiation intensity increases the amount of produced freshwater. It was also observed that applying a TEC on a part of the glass can increase water production from 15% to 62%. The reason for this increase can be the increase in free convection due to the increase in the flow temperature gradient in designed solar still.