Experimental investigation of biochar-based PCM for enhancing solar still desalination of saline water
摘要
Freshwater scarcity is a rising global issue driven by population growth, industrialization, and limited clean water resources, making solar desalination a significant sustainable solution. However, conventional solar stills suffer from low productivity due to poor heat retention, intermittent solar radiation, and limited thermal storage. This study is motivated by the need for an efficient, low-cost, and eco-friendly energy storage material to overcome these limitations. The proposed approach incorporates biochar-based phase change materials (PCMs), established from wood, coconut shell, and rice husk biochar united with paraffin wax, stearic acid, and erythritol, to improve thermal performance. The main objective is to expand heat transfer, temperature stability, and freshwater production in solar stills. The methodology involves experimental evaluation of thermal energy storage, desalination performance, and efficiency under varying solar conditions. Key contributions include composite development, performance analysis, and optimization for practical application. The study demonstrates enhanced desalination efficiency, prolonged operation beyond daylight, and enhanced sustainability for scalable freshwater production. The methodology involved designing and experimentally assessing a biochar–PCM-integrated solar still under varying solar irradiance, ambient conditions, and material configurations. Performance was evaluated through thermal behavior, freshwater yield, efficiency, and water quality analysis. Key findings show improved basin temperature up to 63.8 °C, yield reaching 8.6 L m−2 day−1, thermal efficiency of 71.8–74.2%, reduced heat loss to 17.9%, and high stability with TSI of 0.91. Machine learning validation confirmed strong predictive accuracy (