The Construction And Performance Simulation Research Of The Double-evaporator Opening And Closing Combined Heat Pump Drying System

For domestic agricultural stage heat pump dryer is less efficient at low temperature north,the problem of higher exhaust gas temperature,applicable to the design and manufacture of a low temperature heat drying conditions agricultural equipment,simulation bench setup and system performance.First,the theoretical analysis of heat pump drying air circulation mode,several features contrast cyclic manner,the choice of using closed air circulation and the air source heat pump heating mode humidity drying binding design,the main use of simple closed cycle design,by Ambient temperature has little effect,Advantages humidity air source heat pump heating cycle mode under high humidity conditions of efficiency,Selection of Enthalpy Enrichment to Solve the Problem of Poor Heat Pump Heating Capacity at Low Temperature.Literature review by conventional heat pump refrigerant,the heat pump compares the performance of various refrigerants,R410 A refrigerant selected.Then,through the design and calculation of the heat pump system,the selection of the main equipment of the heat pump system was determined,and an open-close combined heat pump drying system experiment platform with double evaporator and enthalpy increase function was built,and the test system was established.Finally,use Excel to establish a heat pump system simulation model,compare the system performance changes under different supplemental air pressures,study the effect of supplemental air volume on the heat pump system performance at different evaporating temperatures,and compare the dehumidification efficiency of the two circulation methods under different conditions.The simulation results show that the increase in enthalpy by supplemental air can effectively reduce the compressor discharge temperature and improve the performance of the heat pump system under low temperature conditions.When the evaporating temperature is higher than 0℃,the system’s best supplemental air volume is 12.3%～13.9%,and the system’s best intermediate supplementary pressure is 1.278 ～1.498 MPa.When the evaporating temperature is-15 ～ 0 ℃,the system’s best supplemental air volume When the evaporating temperature is lower than-15℃,the optimal air supplement volume of the system is 20-24%,and the intermediate air supplement pressure is 0.898～1.078 MPa.Under the same conditions of air temperature,humidity and air volume,the dehumidification efficiency of the air source heat pump heating dehumidification drying cycle is higher than that of the closed cycle.