Theoretical and experimental studies of immediate assisted solar air gap membrane distillation systems

Abstract

A new design of the air gap membrane distillation (AGMD) system equipped with a solar absorber was investigated theoretically and experimentally for saline water desalination, which integrated the immediate assisted solar (IAS) absorber as an additional heat supply source and the AGMD process to produce high purity water, say the IAS–AGMD system. The theoretical formulations were developed and the resultant equations were solved by the Newton–Raphson method. The theoretical predictions show that the IAS–AGMD system accomplishes a better device performance in pure water productivity than that of the conventional AGMD system. The good agreement was achieved between the theoretical predictions and the experimental runs in the present study. The effects of the fluid inlet temperature, volumetric flow rate, air gap thickness, and incident solar radiation on the heat transfer efficiency and pure water productivity were also delineated. The theoretical results indicate that the pure water productivity increases with increasing the inlet temperature of hot fluid, volumetric flow rate, and incident solar radiation but with decreasing the air gap thickness and inlet cold fluid temperature. Moreover, the theoretical prediction of the optimal process thermal efficiency in the IAS–AGMD system was obtained as the air gap thickness is 2.5 mm.