Experimental investigation of the use of vacuum assisted microwave ovens in fabric drying

This thesis investigates the drying of wet or moist fabrics and various textile materials using Vacuum Assisted Microwave (VAM) ovens and evaluates the effects of this method on energy efficiency. Conventional drying systems have significant drawbacks, including high energy consumption, long processing times, and large space requirements. In contrast, vacuum-assisted microwave technology offers a sustainable alternative for the textile industry due to its lower investment cost and compact system design. Within the scope of this study, a laboratory-scale, custom-designed VAM drying system was developed and manufactured. The system comprises a modified microwave oven operating at 2450 MHz, a stainless steel vacuum chamber, a radiator designed to protect the vacuum pump from vapor-induced damage, a specially designed condenser unit filled with steel wool, and an interconnected vacuum line. Experimental studies were conducted using fabric samples with different moisture retention characteristics, including 100% polyester, 100% cotton, and polyester/cotton blended fabrics. Drying experiments performed at a microwave power of 600 W and a vacuum pressure of −0.8 bar revealed that hydrophobic polyester fabric achieved a drying ratio of 94% within 60 seconds. In contrast, hydrophilic cotton fabric reached a drying ratio of 66% under the same conditions. The developed condenser unit effectively absorbed the latent heat of the vapor released during the drying process, resulting in an approximately 11 °C increase in radiator surface temperature while maintaining stable vacuum conditions throughout operation. The results confirm that the VAM method is a rapid and energy-efficient drying technique for textile applications. KEYWORDS: Vacuum Assisted Microwave Drying, Textile Drying, Energy Efficiency, Vacuum technology