Energy-Efficient Microwave Heating: Governing Role of the Thermal Profile in Heating Liquid

Microwave heating is widely used because of its advantages of selective heating, internal heating, high efficiency, and easy controllability. With the proposal of efficient production and high-quality products, the advantages of microwave heating such as high efficiency and fast heating speed are becoming more and more apparent. The results of this article have shown that the optimum energy consumption of the microwave source, i.e., the optimum temperature rise curve of the heated material during the microwave heating process, can be obtained by precise control of the microwave source with the switch control circuit. Moreover, for the same material, under the same starting and ending temperatures, identical processing parameters such as heating time and different temperature rise curves could result in different microwave energy consumption. Proper temperature rise curves enable about a 10% reduction in energy consumption during the microwave heating period. Moreover, by controlling the start and stop of the microwave source, ideal temperature rise curves can be obtained─the temperature rise curves not only enable accurate control of the temperature of the heated object to avoid excessive temperature debasing product quality but also can achieve diverse heating purposes such as decreasing energy consumption and improving evaporation speed.