Design And Simulation Of A Multi-function Air Source Heat Pump Drying System

Improving energy efficiency and environmental protection has become the basic national policy of sustainable development in China.Drying is an important process in the production process of industry,agriculture and food processing industry,and it is a high energy production process.In the production process of agricultural and sideline products and food processing industry,the drying device and its process control are closely related to the quality,production efficiency and processing cost of the dried products.On the basis of previous studies,according to the diversity of agricultural products processing objects,the variability of drying process,the uncertainty of climate environment and the requirements of energy saving and emission reduction,a multi-functional regenerative air source heat pump drying system was designed.The main work and innovation results are as follows:(1)The present situation of dry processing of agricultural products in the south of Anhui Province was investigated,and the development of heat pump drying technology at home and abroad was searched and analyzed.A multi-functional regenerative air source heat pump drying system with good environmental adaptability was designed,which can realize four working modes: rapid heating,closed,open and semi open mode,to meet different kinds of drying and processing needs of agricultural products;(2)The design and calculation of regenerative heat pump drying system were carried out,including selection of compressor,design and calculation of evaporator and condenser of heat pump system,and design of separate heat pipe assembly;(3)The heat pipe heat transfer performance test bed was built,and the heat transfer performance test of the heat pipe under different working conditions was carried out to study the working characteristics of the heat pipe;(4)A mathematical model of heat pump drying system was set up to simulate the influence of the change of cycle parameters on heat pump drying system under different internal and external conditions on the performance of heat pump drying system,the result reveals that: The heating capacity and COP of the heat pump system are decreased with the increase of the inlet air temperature and increased with the increase of the ambient temperature,the range of energy efficiency varies from 3 ~ 5.7;(5)On the basis of the above research,the performance of the regenerative heat pump drying system is simulated: The larger the heat transfer temperature difference is,the larger the over-flow air volume is,the higher the heat transfer of heat pipe regenerator is.The heat transfer temperature difference increases from 5℃ to 25℃,and the energy efficiency can be increased by 8%~33.7%;(6)Heat pipe regenerator can fully recover the exhaust heat of the drying chamber,the system heating performance can be increased by 10%~15%,the evaporator dehumidification capacity can be increased by about 12%,the regenerator positive effects on improving energy efficiency and energy-saving of heat pump drying system.