The investigation of heat absorber on the efficiency of slanted double-slope solar distillation unit

Abstract

A rise in utility consumption in rural areas have promoted the demand for the development of solar-based technologies for water purification system. This research aimed to develop a slanted double-slope solar distillation unit (SDSD) assisted by heat absorbers, which is employed as a distillation unit for generating clear distilled water from underground water. The prototype SDSD distillation unit developed in this research was evaluated based on production efficiency, productivity, distillation rate and temperature measured at different locations inside the device. Significant parameters that were varied included the types of heat absorber used (gasket, rubber, aluminum, high carbon steel and zinc) and the size of heat absorber (10 to 90% of surface area inside the SDSD). Results demonstrated an increase in the production of distilled water as the surface area of heat absorber decreases. This is because a reduction in surface area of the heat absorber allowed a more intense sunlight to enter the system. Maximum productivity peaked at 1.2 liter per day (24.9% efficiency). Monitored data in both the upper and bottom part of the distillation unit revealed the highest distillation rate at 15:00 each day. Distillation rate decreases with water height and insulator's thermal conductivity, but increase with water speed. Additionally, a mathematical model was proposed which was capable of accurately predicting the production efficiency and productivity as a function of the heat absorber's size and distillation time. Under the same operating conditions, aluminum was found to generate the best results relative to other types of heat absorber.