Employing Phase-Change Materials to Enhance the Thermal Performance of the Solar Dryer

Solar drying systems are extensively employed in agriculture for the dehydration of crops, fruits, and vegetables due to their ability to generate higher temperatures, thereby resulting in enhanced drying efficiency and product quality. However, the excessive air temperature often encountered in solar drying systems can potentially compromise the quality of agricultural products. Moreover, these systems rely solely on solar energy and thus cannot operate during nighttime. To control the drying temperature and prolonging the operation period are important to improving solar drying systems. The efficient heat storage capacity of phase change material (PCM) makes it a potential choice to store the daytime heat to lower excessive air temperature and then release this heat during nighttime to prolong the drying time. To explore the operation efficiency of PCM, integrating the PCM with the Traditional Solar Dry System (TSDS-PCM) was built with referring to a Traditional Solar Drying System (TSDS). The experimental results demonstrated that the PCM presence had adjusted the air temperatures in the drying chamber by reducing the peak air temperature by 14.8 °C and increasing the average air temperature by 2.1 °C. Meanwhile, the efficient operation time of the solar drying system was prolonged by 3.25 h, which led to a shortening of the drying period by 35.29 %. Although TSDS-PCM has lower collector efficiency than TSDS, it can output the heat energy of 1967.23 kJ at night, which was 1743.45 kJ higher than TSDS.