Theoretical And Experimental Study On PVTx Properties Of Mixed Refrigerants

As Ozone Depletion and Global Warming set an strict environmental standard for refrigerants,traditional Hydrochlorofluorocarbons(HCFCs)and Hydrofluorocarbons(HFCs)are being phased out in coming years.Developing different kinds of mixed refrigerant for different occasions is one of the research highlights.New mixed refrigerant Trans-1,3,3,3-Tetrafluoropropene/imethylehter/1,1,1,2-Tetrafluoroethane(R1234ze(E)/RE170/R134a)is a patent jointly developed by Zhejiang University and Zhejiang Juhua Corp.This new refrigerant is featured good performance and meanwhile satisfies environmental requirements through combining advantages of each pure component.This article mainly focus on the Pressure-Volume-Temperature-Compsition properties(pVTx)of the new refrigerant.Main contents are as following:(1)A pVTx measurement apparatus was developed and tested for experimental needs,which could work on temperature range from 203 to 523 K and pressure range from 0.0 to 6.0 MPa.The standard uncertainties were determned to be 5 mK for temperature and 1.5 kPa for pressure.The accuracy was determined to be high compared with open literature.(2)pVTx properties of binary systems R134a/RE170,R134a/R1234ze(E),R1234ze(E)/RE170 and ternary system R1234ze(E)/RE170/R134a were measured and a total of 434 experimental data points were collected to establish the virial type equation of state in gase phase.The pressure and density deviations generated by these equations were determied to be within ± 0.55%in pressure and ± 0.60%in density for binary systems and ±1.13%in pressure and ± 1.36%in density for ternary system.(3)The equation of state used in this article was analyzed and a stepwise regression algorithm was adopted to optimize the structure of eqaution of state.The accuracy of optimized equation of state is improved.