Experimental Investigation on Single Slope Solar Still Integrated PCM-Bamboo Biochar Composites for Sustainable Water Production

This study investigates a novel Composite Thermal Energy Storage System (CTESS) that incorporates the bamboo biochar with a paraffin wax-based Phase Change Material (PCM) to enhance the thermal performance and distillate of a solar single-slope desalination unit. The composite storage material was incorporated into the basin of a solar desalination system and investigated under three configurations: a conventional solar desalination system (CSD), a solar desalination system with paraffin wax as the thermal storage medium (SDPW), and a solar desalination system integrated with bamboo biochar-based paraffin wax composite (SDBBPW). The inclusion of bamboo biochar enhances the thermal conductivity of the thermal storage medium approximately five times compared to pure paraffin wax, resulting in sustained evaporation beyond peak sunshine hours, under the typical climatic conditions in Karaikal, Puducherry, U.T. of India, during the month of March. In addition to freshwater yield, the thermal and economic assessment of the systems was evaluated. The results indicate that the CTESS significantly improves operational effectiveness compared with both CSD and SDPW systems. Comparative analysis demonstrates that the SSBBPW system exhibits superior performance to the CSD and SDPW systems, achieving a maximum daily freshwater output of 4,120 ml/m² and having a thermal efficiency of 57.77%, surpassing the SDPW (54.12%) and CSD (45.57%) under a peak solar irradiance of 1206 W/m² recorded in March. The overall results highlight the potential of bamboo biochar with a paraffin wax-based Phase Change Material as a sustainable and economically viable solution to enhance the thermal performance of solar desalination systems, particularly in regions with freshwater scarcity.