Experimental Study on a Passive Solar Desalination Unit Associated With Fresnel Lens and Thermal Storage

Abstract

Passive solar stills can be a viable source of freshwater in water and energy scarce regions. However, the low production rate is one of the major drawbacks of passive solar stills. This work presents an experimental study of the combined effects of concentrated solar power (CSP) and phase change material (PCM) on a low-cost double slope passive solar desalination unit. Fresnel lens as the refractive CSP was used to converge the available solar irradiation onto the solar still basin that contained saline water. Metal tubes containing petroleum jelly with a melting point of 37°C were immersed as the PCM in the saline water. Four different experimental setups were tested in the natural tropical weather of Malaysia to identify the individual and combined impact of the lens and petroleum jelly on desalination performance. It was observed that the performance was better with the individual application of the CSP rather than the combination of CSP and PCM. There was a 28.21 % improvement in distillate production using Fresnel lens only; while using the Fresnel lens and PCM in combination showed a 25.64 % improvement in production. This study also provides several recommendations with which the experimental setup can be improved to yield better results in the future.