System optimization of solar-based atmospheric water generator

This paper presents an innovative approach addressing the problem of clean and drinking water scarcity by developing and optimizing a flow-assisted desiccant solar still (FADSS) that harnesses atmospheric moisture using solar energy. It is an extension of the conventional desiccant solar still incorporating a small blower to facilitate airflow through the system, and operates in a two-cycle process. During the night (adsorption process), ambient air is blown continuously through the bed, enabling the silica bed to adsorb moisture. During the daytime (desorption process), solar energy heats the silica bed, releasing the adsorbed water vapour to the circulating air, which carries it to the condenser. The water vapour condenses in the condenser, and the air returns to the bed. The paper focuses on optimizing the FADSS by studying the airflow rate, a critical parameter for maximum water production. It varies from 20 to 60 L per minute (LPM). Further, the paper also investigates the four different bed design configurations for maximum water production. The FADSS thermal efficiency is calculated to analyze its performance. The highest water production of 694 ml/day was achieved using a 0.25 m2 glazing area in the honeycomb bed design. This output was obtained by employing an airflow rate of 30 LPM and a 3 cm thickness of silica gel. Interestingly, The honeycomb bed effectively utilized ∼38 % of solar energy for water production in the FADSS, while about 9 % was lost due to sensible cooling of the air in the condenser. The findings suggest that the honeycomb bed, with an airflow rate of 30 LPM, represents the optimal operational parameters for this system.