Research On Thermophysical Properties And Cycle Performance For Binary Mixtures Containing R1234ze(E)

The refrigerant R22 has a non-zero ozone depletion potential(ODP)and a high global warming potential(GWP).Driven by increasingly stringent environmental regulations,the search for a refrigerant to replace R22 has become a hot research topic in the field of heat pump air conditioning.R1234ze(E)has zero ODP and only 6GWP,which has excellent environmental performance.However,the thermophysical properties of R1234ze(E)are not ideal,and it is a feasible idea to mix other refrigerants in R1234ze(E)to form a binary mixture to improve the defects of R1234ze(E)in thermophysical properties.At present,there are few studies on the thermophysical properties and cycle performance of binary blends containing R1234ze(E).In order to provide a reference for R22 replacement,this paper takes 10 binary blends containing R1234ze(E)as the object of study and focuses on their thermophysical properties and cycle performance.First,the Helmholtz equation of state for each mixture is optimized by minimizing the objective function using the experimental data of vapor-liquid equilibrium of 10 binary mixtures containing R1234ze(E)in the literature.The average absolute relative deviation of the optimized Helmholtz equation of state is generally within 1% when calculating the bubble and dew point pressures for each mixture,while the average absolute relative deviation of the thermal property calculation software REFPROP9.1 is generally between 2.159 and 5.994%.Then,the Helmholtz equation of state was used and combined with the thermodynamic equation to establish the thermal property calculation model expressed in the form of dimensionless Helmholtz free energy,based on which the standard boiling point,temperature glide,saturation vapor pressure and constant pressure specific heat capacity of the binary mixtures containing R1234ze(E)with different mass ratios were calculated and compared,and it was found that: At standard atmospheric pressure,azeotropic points exist for R1234ze(E)/R13I1,R1234ze(E)/R290 and R1234ze(E)/R600 a at R1234ze(E)mass fractions of 0.45,0.27 and 0.75,respectively.R1234ze(E)/R134 a,R1234ze(E)/R1243 zf and R1234ze(E)/R152 a exhibited good near azeotropic properties with temperature glides below 1°C throughout the proportioning interval.Finally,nine binary blends containing R1234ze(E)in specific ratios were chosen according to the principle of giving priority to environmental performance and taking into account safety performance and thermophysical properties,and the cycle performance of these blends in heat pump air conditioners was investigated.It was found that: under standard operating conditions,R1234ze(E)/R32(named MIX04)with a mass ratio of 0.58/0.42 had the best performance was found.The unit volume cooling capacity and unit volume heating capacity are 4% and 8% higher than R22 respectively,although the cooling coefficient of performance and heating coefficient of performance are 10% and 7% lower than R22 respectively,but under the annual working condition at the hot summer and cold winter region,the average coefficient of performance of MIX04 is 4.52.In summary,MIX04 can be used as a potential replacement for R22 in heat pump air conditioners.