Effect of Adding Ambient Air Before Evaporating on Multi-stage Heat Pump Drying System
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Drying is a high energy consumption process, accounting for more than 12% of total industrial energy consumption. It is therefore urgent to develop newer energy-efficient and saving structures and processes to replace the traditional drying equipment. In this paper, a multi-stage heat pump drying system is proposed. Based on the theoretical simulation, drying energy efficiency was studied by analyzing energy grade and moisture content between the exhaust gas and ambient air. The results show that: SMER increases by up to 12% when winter ambient air is added before evaporating, and moisture condensation has some influence on SMER and water removal rate. Both temperature and relative humidity of ambient air affect the system performance. Therefore, specific control strategies for ambient air ratio during different seasons may solve the low energy recovery rate of exhaust gas, and also improve the efficiency of energy consumption.
KeywordsDrying Multi-stage heat pump Ambient air Moisture condensation Saving energy
This work is supported by the Key Technology Research Project of Science and Technology Commission of Jilin province, China (No. 20180201006SF) and the Development and Innovation Project of Science and Technology Commission of Jilin city, China (No. 201750214).
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