Numerical simulation of the performance of passive and active solar still with corrugated absorber surface as heat storage medium for sustainable solar desalination technology

Abstract Groundwater is the most important and valuable water resource in arid and semi-arid regions. Nevertheless, the high salinity of these resources remains the major constraint. To remedy this problem, the present study aims to investigate and develop a novel sustainable solar desalination technology. A passive and active single slope solar still, combined with phase change material (PCM) for the thermal energy storage system, have been numerically modeled and simulated. The active system has been made by coupling passive solar still with a parabolic trough collector (PTC) via a heat exchanger , as an external heat source. For each desalination system, a flat absorber and others with corrugated surfaces (rectangular, triangular, and spherical) were tested to compare their performances and the effect of absorber shape on both passive and active systems. Conservation equations of the two models were solved using Comsol Multiphysics software. Simulation results showed that for the passive system the corrugated surface with rectangular ripples increases pure water productivity by 109% and 42% by comparison with the conventional distiller, and the distiller with an absorber of flatform with storage system, respectively. Furthermore, it was revealed that solar still integrated with PTC and modified by different absorber geometry has higher freshwater productivity of 15.39 and 15.01 kg/m 2/day compared to 2.37 and 2.11 kg/m2 /day for the passive still by using rectangular and spherical absorbers respectively. Consequently, the percentage improvement of the developed active system is about 549.36% and 611.37% respectively. From this investigation, it is observed that the passive solar still with rectangular absorber is the most suitable for household use; however, by coupling PTC to the modified passive solar still with rectangular absorber configuration, we have the appropriate design for industrial applications such as hospitals, irrigation processes for agricultural greenhouses in arid and semi arid regions .