Solar still performance enhancement with reflectors and various shapes of absorber plates

Abstract

Considering the importance of desalination and the freshwater crisis in the world, as well as the low efficacy of solar still distillation systems, it is important to enhance the productivity of solar desalination systems using proper techniques. In this experimental study, two devices were built and two methods were applied to improve the productivity of solar still systems. The first method is to corrugate the absorber plate to have higher surfaces for evaporation and solar radiation absorption, and the second method is to use reflective mirrors. So far, various methods have been used to enhance the performance of the solar stills, but in this study, for the first time, the simultaneous effect of using upper and lower reflective mirrors and different geometries of the absorber plate on the efficiency enhancement of solar still systems have been investigated. The purpose of this study is to conduct several tests on the solar desalination devices with reflectors and different absorber plates, including a simple absorber plate, a triangular absorber plate. The reflectors are used to increase the solar radiation absorption by the evaporation unit of the solar desalination device. It was found that the production of freshwater is higher by using the triangular absorber plate as compared with square and simple absorber plates. The use of reflectors significantly increases freshwater production during the afternoon hours. The lowest cost of 0.036 $/L/m2 for producing freshwater belongs to the solar still with an external reflector and a triangular absorber plate. The highest daily efficiency of 32.1% was reported for the solar still with a reflector and a triangular absorber plate. Using a reflector in the solar still system enhances the efficiency of freshwater production by 26% compared to a desalination system without a reflector. Using a triangular absorber plate and a square absorber plate in a solar still increases the efficacy of freshwater production by 25.7% and 20%, respectively, compared to a desalination system with a simple absorber plate.