Experimental investigation of the effects of low-temperature phase change material on single-slope solar still

Abstract

Conventional desalination plants mostly require high energy levels, which could produce high levels of carbon dioxide, if provided by fossil fuels. While this energy could be efficiently provided by solar energy, this energy's intermittent nature is an excellent barrier to this approach. Incorporating phase change materials (PCM) in desalination units could help achieve a more prolonged desalination process. In this experimental study, a PCM-enhanced single-slope solar still is investigated regarding the effect of low-temperature PCM on the overall productivity and efficiency and basin temperature parameters. For this purpose, a commercial salt hydrate low-temperature PCM with the melting point of 28 °C and latent heat of fusion of 225 kJ/kg was selected as a novel approach in this field. Three test cases, including still without PCM, still with 3 kg of PCM, and still with 6 kg of PCM were investigated. During each experiment, the operational temperature, hourly and cumulative productivities, and desalination efficiency were measured and calculated. It was found that adding 6 kg of PCM could enhance the overall productivity by 30.3% while increasing the desalination efficiency from 28.13% to 36.42%. The results show that low-temperature PCMs could be efficiently utilized to improve the solar stills' performance.