Performance Assessment of a Solar Dryer System Using Small Parabolic Dish and Alumina/Oil Nanofluid: Simulation and Experimental Study

Abstract

In this study, a small dish concentrator with a cylindrical cavity receiver was experimentally investigated as the heat source of a dryer. The system was examined for operation with pure thermal oil and Al2O3/oil nanofluid as the working fluids in the solar system. Moreover, the design, the development, and the evaluation of the dried mint plant are presented in this work. Also, the solar dryer system was simulated by the SolidWorks and ANSYS CFX software. On the other side, the color histogram of the wet and dried mint samples based on the RGB method was considered. The results revealed that the different temperatures of the solar working fluids at the inlet and outlet of the cavity receiver showed similar trend data compared to the variation of the solar radiation during the experimental test. Moreover, it is found that the cavity heat gain and thermal efficiency of the solar system was improved by using the nanofluid as the solar working fluid. Furthermore, the required time for mint drying had decreased by increasing the drying temperature and increasing air speed. The highest drying time was measured equal to 320 min for the condition of the air speed equal to 0.5 m/s and the drying temperature of 30 °C. A good agreement was observed between the calculated numerical results and measured experimental data. Finally, based on the color histogram of the wet and dried mint samples, it was concluded that intensity amount of the red color of the mint increased with the drying process compared to intensity amount of the red color of the wet mint sample.

Recent advances in solar drying technologies: A Comprehensive review

“…A solar dish concentrator with a cylindrical cavity receiver is used for drying mint. Pure thermal oil or Al2O3 acts as a solar working fluid [54]. A mixed type of solar dryer has been developed for drying tomatoes and is integrated with 15 temperature sensors, humidity sensors, a moisture analyzer, and a hot wire anemometer used to measure temperature, humidity, moisture, and wind velocity respectively [55].…”

A detailed investigation of the temperature-controlled fluidized bed solar dryer: A numerical, experimental, and modeling study

“…Solar thermal collectors can be classified into two groups: solar water collectors and solar air collectors (SACs). Both mentioned solar collectors can be utilized in solar drying applications [9,10]. Generally, air collectors are preferred in solar drying processes because of their simple and cost-effective structures [11].…”

Annual Thermal Performance of an Industrial Hybrid Direct–Indirect Solar Air Heating System for Drying Applications in Morelos-México

“…In the literature, most solar air heating devices for drying are for low capacities and a reduced solar collector area [14][15][16][17][18][19][20][21][22][23]. The studies are few at an industrial scale.…”