Design And Operational Simulation Of Heat Pump System In Milk Collection Station

The technology of Energy's development and utilization marks the continued evolution and development of human society. Therefore, in order to use energy in a higher level, the technology that can reduce energy efficiently or can recycle energy in the production process is very important, when there is a relatively low temperature geothermal energy or waste heat emissions in the production process. The heat pump system is able to recover more heat energy and achieve low temperature heat recovery for high temperature process, compared the heat recovery equipment by heat exchanger.This paper designs heat pump system which is applicable to milk collection station, according to it's heating and cooling characteristics. This system can recovery condensing heat which will used to heating cleaning water when cooling milk. The heat exchanger used to cooling milk is designed to meet the health standards of the food industry and easy to be cleaned, because the milk is not only vulnerable to deterioration, but also easy bonding in the container wall. The main components of the heat pump machine such as compressor, condenser, evaporator and expansion valve are designed and selected according to the heating and cooling characteristics and milk output in a milk station. To the heat pump unit in milk stations, the main purpose of the study is to predict the dynamics performance of a particular structure heat pump unit in the specific operating mode, such as milk temperature at evaporator's import and export, water temperature at condenser's import and export, milk temperature in the milk tank, water temperature in the water box, compressor's power, cooling capacity and other operating parameters.A physical&dynamic mathematical model of the MSHP system are made with the mechanism modeling method, to achieve cooling milk in the required time, preservation fresh milk and heat recovery,besides dynamic operating simulation programs are made with the help of Matlab/Simulink. From the simulation results, we can know that the heat pump system could cooling 1.0t milk from35℃to 6℃in the required time 2 hours, at the same time, 0.5t water can be heated to 53℃by the recovery condensing heat. The system's average COP is 2.6 in the entire operation process, while heat pump unit's COP can achieve 3.5. This paper uses the annual-cost method to comparing the heat pump system with traditional system from the original investment and running cost in the milk station of output 1.8t p.d, gets the result that the original investment of heat pump system is 106% of the air cooling tank&bliler heat system's, however the annual running cost of heat pump system is 66% of the air cooling tank&bliler heat system's. The annual-cost of air cooling tank&bliler heat system is 37634yuan, while the heat pump system's is 26867yuan, it can be seen using the heat pump system is more economical in the milk station.