Development, Thermodynamic Evaluation, and Economic Analysis of a PVT-Based Automated Indirect Solar Dryer for Date Fruits

Abstract

The present study focuses on the development, thermodynamic evaluation, and economic analysis of a photovoltaic-thermal (PVT)-based automated mixed-mode indirect solar dryer (AMMISD). The developed AMMISD was used for drying five date varieties native to the Aswan area, namely Shamia, Bartamuda, Sakkoti, Malkabii, and Gondaila. The initial and final moisture contents of date varieties ranged between 15.7% and 17.2% and 4.91% and 6.41%, respectively. All date fruit varieties reached equilibrium moisture content after 6 days (60 h) compared with 14 days (140 h) in a traditional indirect solar dryer (SD) and 14–25 days (140–250 h) under open-air sun drying. The energy analysis of both the solar air collector (SAC) and the SD showed that the SAC efficiency and the drying efficiency were in the range of 15.15–63.33% and 4.01–4.41%, respectively. Additionally, the exergy analysis of the SAC and drying room (DR) revealed a maximum efficiency of 27.5% and 96.62%, respectively. The improvement potential (IP) ranged from 4.62 to 13.64 W, the mean value of waste exergy ratio (WER) was 0.84, and the sustainability index (SI) ranged from 1.01 to 1.38. Moreover, the economic analysis showed substantial economic advantages for date fruit drying, yielding annual savings of approximately USD 236.9, with an investment recovery period of about 2.091 years.