Performance investigation of a novel solar direct-drive sweeping gas membrane distillation system with a multi-surface concentrator

Abstract

Solar membrane distillation is a promising solution to overcome water shortage. However, developing a portable and highly efficient solar membrane distillation system is still a complex task. This work proposes a novel solar direct-drive sweeping gas membrane distillation with a multi-surface concentrator for families in rural areas. The optimized concentrator greatly improved the working temperature of the feed and the membrane distillation with sweeping gas configuration reduces the energy loss which both improve the performance of the system. Based on the optical simulation, a high optical efficiency optimized concentrator (over 70% within the incident angle of 20°) was designed. By conducting outdoor experiments and mathematical simulation, the effects of operating parameters and the concentrator on the system's performance were investigated. The experimental results indicate that the highest energy efficiency and the water production per collector area of the system with the concentrator reach 0.68 and 5.1 kg/m2/d. Simulation results show that the water yield increases with the increase of the irradiance and inlet air temperature and decreases with the seawater salinity increasing. The economic analysis suggests that the levelized cost of water and the payback period are $5.9/ton and 3.4 years respectively.