Performance evaluation of a vertical rotating wick solar still

In this work, a new solar still desalination system named vertical rotating wick solar still (VRWSS) was investigated experimentally. The experiments were performed under different operating conditions. The performance of VRWSS was investigated under different wick belt materials (jute and cotton cloth), belt rotational speeds (0.02, 0.05, 0.1, 0.2, and 0.3 rpm), and rotating directions (clockwise and counterclockwise) with and without solar tracking. The VRWSS features are its small size (small horizontal area), fast water evaporation and condensation due to the low thermal capacity and large condensation area. The results revealed that the jute wick obtained higher productivity than the cotton wick at all belt rotational speeds except that at 0.02 rpm. Additionally, the water production for VRWSS-counterclockwise movement increased from 4350 mL/m2.day at 0.02 rpm to 5800 mL/m2.day at 0.05 rpm, then, the productivity started to decrease with increasing the speed. Furthermore, VRWSS productivity with counterclockwise movement was always larger than that with clockwise direction at all rotational speed except at 0.02 rpm. Besides, the solar tracking for VRWSS (jute wick-counterclockwise-0.1 rpm) increased the freshwater productivity by about 37% with a thermal efficiency of 51%. The cost of produced freshwater from VRWSS was 0.02 $/L.