THE JOURNAL OF KMUTNB

Volume 31, No. 04, Month OCTOBER, Year 2021, Pages 638 - 650

Energy and exergy analysis of solar dryer for rubber sheet drying

Wasan Jeentada, Banyat Niyomvas, Apichit Srichairattana

Abstract Download PDF

This research is to study rubber sheet drying process using a solar dryer by analyzing the energy and exergy of the process. In the experiment, the required drying time was 5 days. The air mass flow rates were controlled to 0.248 kg/s for the first day and 0.020 kg/s for the other days. The experimental results on the first day presented that the drying temperature ranged between 32–40°C, the relative humidity ranged between 44–72%, and the solar radiation varied from 428 to 1,089 W/m2. From the second day to the fifth day, the drying temperature ranged from 34°C to 54°C. The relative humidity range was between 27–72% and the solar radiation range was between 136–1042 W/m2. It was found that at the higher air flow rate, the temperature in the drying chamber decreased leading to the higher thermal efficiency of the solar collector. On the other hand, when the lower air flow rate decreased, the temperature in the drying chamber increased bringing about the lower thermal efficiency of the solar collector. Moreover, the solar dryer could provide the specific energy consumption of 31369.27 Wh/kg, specific electrical energy consumption of 465.77 Wh/kg, and the thermal efficiency of 2.11%. In case of the exergy analysis on the first day, the exergy input, the exergy output, and the exergy loss altered in the range of 40–246, 5–166, and 18–81 W respectively. While, during the other days, the exergy input, the exergy output, and the exergy loss varied in the range of 4–91, 2–77 and 1–43 W respectively. It was found that all exergy values on the first day were higher than those of the other days. However, the exergy efficiency of 12–79% on the first day was lower than that of 42–94% on the other days because the higher exergy loss at the higher air flow rate directly affected the lower exergy efficiency.

Keywords

Energy and Exergy; Drying; Solar Dryer; Rubber Sheet

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