Exergy analysis of porous cotton fabric drying process during the domestic air vented dryer

摘要

This study reveals energy and exergy efficiencies of the fabric drying processes during air vented dryer. Exergy models of the drying processes have been formed and each stage is examined in terms of exergetic parameters. Additionally, parametric studies, including the exergy destruction rates, exergy efficiencies, and exergy loss ratios of the system and its components, have been investigated under various operating conditions. The results indicate that the exergy efficiency increases with the increase in drying rate. Heater of dryer is the highest exergy destruction component of the whole dryer and its power significantly affects exergy destruction of whole drying process; while fan and motor of driving drum are lower exergy destruction component of dryer. Use of staged heating model of adjusting heater power based on drying period is found to be an effective method to reduce the exergy destruction rate of dryer and fabric damage caused by over-drying. Specifically, exergy efficiency of dryer can be improved by increasing the heater power during the warm up and the constant rate period, or by decreasing the drying-power during the falling rate and the blow-air period. The fmdings are found to be useful to system design and performance optimization of domestic dryer in term of reducing irreversibility of the drying system.