Development And Application Of Environmental Test Chamber Based On Cascade Refrigeration System

China,as a country with large scale manufacturing industry,has a large demand for environmental test equipment at present,but there is still a certain gap between Chinese technology and that of some foreign countries.So the demand for research and development of multi-functional advanced environmental test equipment is urgent.In this paper,the current Chinese and foreign test standards and methods of environmental test equipment are investigated firstly,which provides the basis for the simulation and structural design of environmental test chamber.Then,according to the specific application requirements,the state points method is used to analyze the system operation under extreme conditions.Based on the system performance coefficient of the best intermediate temperature,a new environmentalfriendly refrigerant R448 A is selected and used.Based on the theoretical calculation results,the simulation of the heat exchangers,the inner box space and the system are studied respectively.The simulation comparison of different types of heat exchanger is realized in MATLAB,which provides the basis for the selection of parts.The difference of temperature field and velocity field of seven different types of inner box structures is studied in Fluent,which determines the design scheme of the chamber structure.In Dymola,the dynamic simulation of the cascade system is studied.According to different refrigeration requirements,a cascade refrigeration system with dual operation mode and cooling capacity output control function is designed.Theoretically,the scenario of electric heating and the size of condenser can be reduced to achieve the purpose of energy saving.Based on the above theoretical research,author independently designed,modeled and built the prototype of environmental test chamber,innovatively used the microchannel heat exchanger as the evaporator to effectively save air space.Experiments data of the actual operations are recorded and analyzed.Finally,the accuracy of the simulation results is verified by experiments,and the application of an advanced cascade refrigeration system which combines new refrigerant,new structure,dual operation mode and cooling capacity regulating circuit in the environment box is confirmed.On this basis,the future development and application of multi-functional advanced precision environmental testing equipment is promising.