Increasing inlet water temperature using condensation heat to improve solar distillation efficiency

Abstract

Increasing the temperature of inlet water is one way to increase solar distillation efficiency. Heat recovery using double glazing is a more straightforward way to raise the temperature of inlet water. In previous studies, the incoming water temperature was raised using additional equipment such as a solar water heater collector or utilizing the heat of wastewater from another water distillation system. The earlier studies' technique caused solar water distillation to be complicated, and the manufacturing cost was expensive. Heat recovery is a process of utilizing heat condensation of water vapor to increase the inlet water temperature. In conventional solar distillation, condensing heat is not used and wasted into the environment. Double glass is two glasses arranged in parallel, one on the top of the other. The distance between the glasses is 2 mm. The bottom glass is a 1 m 2 distillation cover glass. Water flows between the bottom glass and the top glass before entering the distillation model. The inlet water receives heat condensation so that the temperature rises. The increase in temperature causes heat loss to decrease and leads to efficiency improvement. This study aims to reveal the effect of heat recovery using double glazing to improve solar distillation efficiency. The study was conducted with laboratory experiments and simulations. The thickness of the bottom and top glass and the top glass area influence the heat recovery process. This study used two variations of glass thickness, namely 3 mm and 5 mm. The area of the top glass was varied by 0.1, 0.5, 0.7, and 1.0 m 2. The maximum efficiency improvement compared to distillation without heat recovery obtained is 39.6 % with a glass thickness of 3 mm and 51.0 % with a glass thickness of 5 mm achieved in the variation of the top glass area of 0.1 m 2