Study On Drying Process And System Performance Of American Ginseng Heat Pump

American ginseng,as a characteristic agricultural product which is both medicinal and food.It's more and more popular because of its health care effect.In order to change the coal-fired drying equipment in the original production area of American ginseng into electric drying equipment,a set of air source American ginseng heat pump drying system that can switch the operating mode during operation was designed and built.The loading capacity of the system is 4000 kg,the rated heating power is 16.57 k W,and the external dimensions are 11600�3800�2200mm(length�width�height).In Fusong,a study on the drying of American ginseng heat pump was carried out.The study found that the average energy efficiency ratio of heat pump drying system COP_s is 2.18.The energy consumption of heat pump system is converted into coal consumption,which is only41.9%of the coal consumption of the coal-fired hot air drying system.It can be seen that the heat pump drying system has good energy saving effect;The quality of American ginseng heat pump drying products is similar to that of traditional coal-fired hot air drying products.The COP_hp and COP_s of heat pump system decrease as the drying room temperature increases;In Extreme cold area,evaporator frost will cause COP_hp and COP_s to decline rapidly;The COP_hp and COP_s of the closed heat pump drying system are larger than the open heat pump drying system;SMER showed a downward trend as the moisture ratio decreased and there was a large gap between different drying stages.The average SMER was 0.28kg/(k W�h).The drying characteristic test of American ginseng was carried out and the drying kinetic model of American ginseng was established.The test results found that when the drying temperature is increased,the relative humidity of the drying is reduced,and the diameter of the American ginseng is reduced,which will cause the American ginseng to dry faster.The drying quality and characteristics of American ginseng under different drying temperatures and relative humidity were analyzed;The nonlinear fitting of the moisture ratio shows that the Modified Page model is the most suitable drying kinetic model for American ginseng hot air drying;A calculation method of drying kinetics model for the stage-varied drying was proposed.In order to verify the correctness of the method,a verification test of the calculation method was carried out.Comparing the calculated results with the experimental results,the maximum relative error is 7.44%,and the average relative error is only1.78%,indicating that the proposed method of segmented drying kinetic model calculation can be used to analyze the change of moisture ratio in the process of American ginseng stage-varied drying.