Innovative system for enhancing tomato drying performance using evacuated tube solar collectors, thermal storage materials, and reflectors

Abstract

To overcome the limitations of conventional dryers, this work examines the performance of an evacuated tube solar air heater (ETSAH) integrated with an indirect solar drying system, analyzed across three different configurations: (1) conventional ETSAH, (2) reflector-integrated ETSAH, and (3) reflector-integrated ETSAH with latent thermal storage. Furthermore, data collected on product mass changes were analyzed to evaluate key performance indicators, including thermal and exergy efficiency, drying efficiency, and mass reduction trends across different system configurations. According to the field testing results, reflector integration was found to enhance radiation absorption, yielding an outlet heater temperature of 65.2 °C. Dryer efficiency improved from 41.31 % in conventional ETSAH drying to 48.63 % in reflector and thermal storage-integrated drying, demonstrating the positive impact of higher thermal performance on drying capacity. Moreover, the maximum drying rate reached 0.253 kg/h in reflector and thermal storage-integrated drying, compared to only 0.203 kg/h in conventional ETSAH drying at 13:00 h. Regarding the moisture ratio, the three cases achieved final moisture ratios of 0.232, 0.209, and 0.183, each corresponding to average water removal rates of 0.153, 0.158, and 0.163 kg/h, respectively. These results confirm that combining reflectors and thermal storage materials with ETSAH significantly enhances drying efficiency, rate, and consistency, making the system more suitable for practical and sustainable agricultural applications.