Simulation And Optimization Of Cold Storage Refrigeration System Based On EES

The "Status and Trend Report on the Development of China's Cold Storage Industry" released by the China Cold Chain Logistics Alliance in 2017 shows that the annual power consumption of cold storage in China is about 15 billion k W · h.The energy consumption of cold storage is generally high and the total amount of cold storage and power consumption are increasing year by year,which means it is more important to make the cold storage refrigeration system more energy efficient.Optimizing the cold storage refrigeration system is one of the methods to achieve energy saving.Making the refrigeration system run under the best working conditions and configuring more efficient refrigeration equipment can both achieve the goal of optimizing the refrigeration system.However,it is not easy to find the best working conditions,because there are too many factors affecting the performance of the refrigeration system,which makes it difficult to analyze theoretically,and the cost is too high to find the best working conditions through experiments.The conventional methods of developing efficient refrigeration equipment also require extensive experimentation.Through simulation technology,it is possible to simulate the effects of changes in multiple factors and predict the performance of refrigeration equipment and systems.The purpose of this study is to optimize the cold storage refrigeration system through simulation technology.First of all,Mathematical models of refrigeration equipment such as the piston compressor,the horizontal water-cooled condenser and the thermal expansion valve were established.And the operating data of the above refrigeration equipment were obtained through experiments to fit some of their mathematical models,which made the models closer to reality.Then,EES(Engineering Equation Solver)software programming was used to develop simulation algorithms for refrigeration equipment and the refrigeration system.The performance of refrigeration equipment were studied through simulation and the followings were got: the law of the influence of suction pressure and discharge pressure on isentropic efficiency and refrigerant mass flow rate;the law of the influence of the parameters of water and refrigerant on the heat exchange performance of horizontal water-cooled condensersFinally,the refrigeration system was optimized from two aspects based on the method of simulation: the structure of the horizontal water-cooled condenser and the operating conditions of the system.Two results are got through studying: the condenser structure of option 1 is the best;Under the condition of constant evaporation pressure and constant cooling water inlet temperature,if the cooling capacity needs to be increased,it is recommended to decrease the suction temperature properly and increase the water flow rate.Although the established model is only applicable to a limited range,the simulation algorithm and study method can provide some help for the performance study,optimization and control test of the cold storage refrigeration system.