Energy, exergy, economic and environmental analysis of phase change material based solar dryer (PCMSD)

This study investigates the efficacy of a novel Phase Change Material Solar Dryer (PCMSD) using paraffin wax, stearic acid, and acetamide for drying tomatoes, comparing results with traditional open sun drying methods. The PCMSD successfully reduced tomato moisture content to 20.22 % (paraffin wax), 21.52 % (stearic acid), and 13.25 % (acetamide) from an initial 93 %. Comprehensive analyses of the PCMSD collector and drying chamber were conducted, revealing energy efficiencies ranging from 50.02 % to 78.21 % for the collectors and 1.17 % to 18.55 % for the drying process, depending on the phase change material (PCM) used. Specific Energy Consumption (SEC) and Specific Moisture (SM) values for the PCMSD varied between 0.06-0.10 and 9.56-11.94, respectively. Exergy efficiencies for paraffin wax, stearic acid, and acetamide collectors were 2.38 %, 2.52 %, and 2.55 %, respectively, with the drying section averaging 40.43 % to 47.99 %. Economic viability was assessed through annualized cost, savings, and economic payback period, resulting in favourable payback periods of 0.54 to 0.59 years for the PCMSD with three PCMs. Additionally, embodied energy, energy payback duration, and environmental impact metrics, such as annual CO2 emissions, CO2 mitigation, and potential carbon credits, were analysed. Depending on the PCM, embodied energy ranged from 1357.04 to 1609.81 kWh, with an energy payback period of 2.51 to 2.56 years. The PCMSD demonstrated substantial reductions in yearly CO2 emissions and offered potential carbon credit earnings. In conclusion, the PCMSD with the three PCMs exhibited superior drying performance, heightened energy efficiency, and economic feasibility compared to open sun drying, concurrently reducing energy consumption and environmental impact.