A detailed analysis of a novel auto-controlled solar drying system combined with thermal energy storage concentrated solar air heater (CSAC) and concentrated photovoltaic/thermal (CPV/T)

In recent years, the use of solar energy, one of the renewable energy sources, has been increasing in many areas due to its practical, environmental, and economic benefits. Besides, the drying industry is an applied area where solar energy can be implemented. Solar drying systems are used in the industry to reduce high drying costs and to obtain better quality products. In this study, a novel solar drying system was designed by combining concen-trated solar air collector (CSAC) and concentrated photovoltaic/thermal system (CPV/T). In addition, the automation system has been integrated for data acquisition from the system and humidity-temperature control of the drying chamber. The SAC's inlet air was preheated by a heat exchanger using thermal energy from the PV/T. The drying system has been designed to be more useful by using phase change material in the collector. Thus, the drying process can be performed on cloudy days and after sunset. In addition, the designed system can generate electricity from the PV module to meet the electricity requirement. The mint which grows in various regions worldwide was chosen as the product to be dried in this study. Mint was dried from the first moisture content of 3.3125 g water/g dry matter to the last moisture content of 0.0625 g water/g water/g dry matter. Besides, the average overall efficiency of the system, PV module electrical efficiency, and drying efficiency were found to be 61%, 10%, and 26%, respectively. Furthermore, the average system exergy efficiency, PV module exergy effi-ciency, and concentrated solar air heater exergy efficiency values were calculated as 20%, 16%, and 21.9%, respectively. In the experiment, the ambient average temperature was 22 degrees C, while the average drying chamber temperature was 30 degrees C. The mint drying quality efficiency was 67% on average at this drying chamber tem-perature. The energy, exergy efficiency, and sustainability index of the system were calculated as 61%, 38.8%, and 1.69, respectively. Moreover, the enviro-economic cost of the system was determined to be 0.39 (SIC)/h.

Automated summary

In recent years, there has been an increase in the use of solar energy due to its practical, environmental, and economic benefits. Solar drying systems have been implemented in the drying industry to reduce costs and improve product quality. This study designed a novel solar drying system that combines concentrated solar air collector and concentrated photovoltaic/thermal system, along with an automation system for data acquisition and temperature control. The efficiency and sustainability of the system were evaluated, and the results showed promising performance.