Mathematical and experimental modelling of heat pump assisted microwave drying

Journal Article · Fri Jan 01 00:00:00 EST 1993 · Drying Technology; (United States)

OSTI ID:6403722

Jia, Xiguo ^[1]

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1. Univ. of Queensland (Australia)

Drying is one of the most energy intensive operations in industry and agriculture. In the quest to increase drying efficiency and product quality, new technologies and methods are constantly being sought. Of these technologies, heat pump assisted drying and microwave drying have proved to be the most promising contenders. In order to achieve a better understanding and provide a computer design tool for heat pump assisted convective and microwave drying, both mathematical modelling and experimental investigations of heat pump assisted microwave dryers have been undertaken in this study. A mathematical model has been developed to predict the steady-state performance of a heat pump assisted continuous microwave dryer, with emphasis on the simulation of heat and mass transfer processes in the evaporator and drying chamber. The model is intend to serve as a design tool in the study of heat pump dryers. To achieve the optimum design, the influences of the key design and operating parameters, as well as the comparison of different drying configurations, have been examined. Based on investigation results, several methods have been proposed to improve the performance of heat pump assisted microwave drying, such as the use of a recuperator. To validate the above mathematical model, extensive drying tests using foam rubber as the test material have been conducted on a prototype heat pump assisted microwave dryer. The prototype heat pump input power was 5 kW with a maximum microwave input power of 10 kW. The experimental performance data confirmed the veracity of the simulation model. The experimental results on drying test materials indicate that with careful design heat pump assisted microwave drying is comparable to convective drying in energy consumption while with a much higher drying speed.

• OSTI ID: 6403722
• Journal Information: Drying Technology; (United States), Vol. 11:4; ISSN 0737-3937
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
DRYERS
MATHEMATICAL MODELS
PERFORMANCE TESTING
COMPUTER-AIDED DESIGN
DRYING
ENERGY CONSUMPTION
FINITE ELEMENT METHOD
HEAT PUMPS
HEAT TRANSFER
INDUSTRY
MASS TRANSFER
MICROWAVE RADIATION
THREE-DIMENSIONAL CALCULATIONS
CALCULATION METHODS
DESIGN
ELECTROMAGNETIC RADIATION
ENERGY TRANSFER
NUMERICAL SOLUTION
RADIATIONS
TESTING
320303* - Energy Conservation
Consumption
& Utilization- Industrial & Agricultural Processes- Equipment & Processes