Performance Study Of Multifunctional Closed Heat Pump Drying System

Drying technology is widely used in various fields,and the drying process in each production process is a relatively energy-intensive process,but it cannot be omitted as a key link.Traditional drying techniques or high energy consumption,or poor product quality,it is difficult to achieve the best of both worlds.Heat pump drying technology is a practical drying technology because of its special drying principle,which is energy-saving and environmentally friendly,and can guarantee the comprehensive quality of products.According to the advantages and disadvantages of the existing heat pump drying technology,this paper proposes a multi-functional closed heat pump drying system,and carries out theoretical analysis and experimental research.The main work contents are as follows:(1)The principle of heat pump drying was introduced,and different forms of heat pump drying systems were analyzed.(2)According to the principle of heat pump drying and the advantages and disadvantages of the existing heat pump drying system,a new heat pump drying system is designed,which can realize various operating modes: heating mode,normal drying mode,constant temperature drying mode and refrigeration mode.(3)The compressor,fin heat exchanger and other components were designed and calculated.According to the calculation results,the equipment model was selected and the components were welded into an experimental prototype and the corresponding control system was designed and installed.(4)The experimental platform was built according to the characteristics of the experimental prototype,and the experimental research was carried out on each model with wet cotton cloth as the research object.The experimental data analysis shows that the results are as follows:(1)Under the same experimental conditions,the heating performance of the heating mode of the multi-functional closed heat pump drying system in the dry preheating stage is increased by 28% and the average coefficient of performance is increased by 71% compared with the conventional drying system;(2)In the constant temperature drying mode,the actual drying temperature is 2.2%compared with the target drying temperature,which can basically achieve constant temperature drying;there are different optimal drying media under different drying conditions and different drying conditions.The flux rate makes the the specific moisture extraction rate(SMER)the largest;when the dehumidification amount is the same,the drying time decreases with the increase of the drying temperature,and the power consumption increases with the drying temperature;the heating capacity increases with the drying temperature.However,when the temperature exceeds a certain range,the coefficient of performance(COP)will decrease;therefore,in the actual drying process,the appropriate drying temperature should be selected and the bypass rate should be adjusted in real time according to the drying medium parameters to optimize the drying performance of the unit.(3)The conventional heat pump drying system has low drying performance,and the maximum SMER is 0.88 kg/(kW·h),which is lower than the constant temperature drying mode of 1.64 kg/(kW·h).(4)Under the test conditions recommended by the standard SB-T10794.2-2012,the supply air temperature in the refrigerating mode reaches a minimum of 4.01?,which can meet the requirements of 7? for commercial refrigerators.The coefficient of performance(COPr)of the system is sent.The wind temperature decreases and decreases.When the supply air temperature is 7?,the COPR is 1.19.When the supply air temperature is 4.01?,the COPr is reduced to 1.04.Therefore,the supply air temperature can be increased as much aspossible according to the actual application requirements to improve the performance of the device...