Experimental study of solar desalination performance due to water depths, flow rates and using heat recovery from disposed brine

The effects of water depth, flow rate and preheating using heat exchanger were investigated experimentally on solar still. The best performance indicated for shallowest depth and lowest inlet flow rate. At the flow rates of 3-5 L/day at depth of 1.5 cm, reducing the flow rate, the freshwater productions for autumn and winter increased 23% and 12%, respectively. At a flow rate of 3 L/day and depth 1.5 cm, using the disposed water from the basin and passing through a heat exchanger increased the amount of production by 15%. Decreasing the basin water depth and flow rate, the energy and exergy efficiencies increased. Further results indicated for solar still with heat exchanger an increase in efficiencies of 3.3% for energy and 0.4% for exergy for the flow rate of 3 L/day and depth of 1.5 cm. Heat exchanger effectiveness was obtained in the range of 10%-49%.