Search

Some experimental data have been published on the basic thermophysical properties of R290, R1216, R1234ze(E) and their mixtures, but the EoV (enthalpy of vaporization) are mostly indirectly calculated by saturated vapor pressure data and Clausius-Clapeyron equation, with limited accuracy, especially for mixtures. Therefore, this paper developed a method to directly measure the EoV of refrigerants and their mixtures based on a microcalorimeter and its supporting equipment. In this work, the enthalpy of vaporization of refrigerants and mixtures has been investigated experimentally and theoretically, and an accurate and simple method for directly measuring EoV has been developed. The EoV of R290, R1216, R1234ze(E) and their mixtures were measured at temperatures from 260 to 290 K using a modified high-pressure differential scanning calorimeter combined with a pressure balance unit and a sample injection system. Compared the experimental results with commonly used estimation methods, such as Clausius-Clapeyron equation and Helmholtz-energy equation of state. The experimental results were in good agreement with Helmholtz equation, with the maximum deviation within 1.89%. The empirical formula was used to fit the experimental results [Display omitted] • A novel method for directly measuring the enthalpy of vaporization of refrigerants and mixture by DSC was proposed. • The enthalpies of vaporization of R290/R1216 and R290/R1234ze(E) at different components were measured. • A novel equation for correlating the enthalpy of vaporization of refrigerants and binary mixtures was proposed. In this work, the enthalpy of vaporization (Δ vap H) of refrigerants and mixtures has been investigated experimentally and theoretically, and an accurate and simple method for directly measuring Δ vap H has been developed. First of all, the Δ vap H of R290, R1216, R1234ze(E) and their mixtures were measured at temperatures from 260 to 290 K using a modified high-pressure differential scanning calorimeter combined with a pressure balance unit and a sample injection system. Seven temperature points were measured for each component. After that, compared the experimental results with commonly used estimation methods, such as Clausius-Clapeyron equation and Helmholtz-energy equation of state. The experimental results were in good agreement with Helmholtz equation, with the maximum deviation within 1.89%. In the end, the empirical formula was used to fit the experimental results. The average absolute deviations between the experimental values and the fitting values were between 0.07% and 0.40%, and the maximum absolute deviations were between 0.11% and 1.05%. [ABSTRACT FROM AUTHOR]

• The VLE data for R1234ze(E) + R1216 binary mixtures were measured at five temperatures range from 275 to 315 K. • The experimental results were correlated with PR-HV-NRTL model. In this work, the vapor–liquid phase equilibrium (VLE) data of R1234ze(E) and R1216 binary mixtures has been investigated experimentally and theoretically. The VLE data for the binary system of R1234ze(E) + R1216 were measured with a recirculation system at five temperatures range from 275 to 315 K. The experimental results were correlated by Peng-Robinson equation of state combined with Huron-Vidal mixing rule or Wong-Sandler mixing rule and non-random two-liquid activity coefficient model, and van der Waals mixing rule. The calculated values were in well agreement with the experimental results, with the maximum deviations of the pressure and the mole fraction of the vapor phase within 0.87% and 0.016, respectively. The average absolute deviations of the pressure and the mole fraction of the vapor phase between the experimental values and calculated values were 0.35% and 0.005, respectively. [ABSTRACT FROM AUTHOR]

• The VLE data of R152a + R1216 were measured at the temperature of 283.15 ∼ 313.15 K. • Experimental data were correlated with PR-vdW, PR-HV-NRTL, and PR-WS-NRTL models. • The azeotropic phenomenon can be observed in the measured temperature range. Compared to pure refrigerants, mixed refrigerants can effectively fulfill the demands of high efficiency, safety, and environmental preservation. An efficient mixture can be created by combining environmentally safe and non-combustible refrigerants with low global warming potential (GWP) and high latent heat hydrofluorocarbons (HFCs) in precise ratios. For this investigation, an experimental apparatus was built to obtain vapor–liquid equilibrium (VLE) data for the R152a + R1216 mixture within temperatures of 283.15 to 313.15 K. To depict the VLE characteristics of the binary systems, the Peng-Robinson (PR) equation of state (EoS) was utilized with the van der Waals (vdW) mixing rule. And to compare, the Huron and Vidal first-order (HV) and the Wong-Sandler (WS) mixing rules were utilized alongside the PR EoS and the non-random two-liquid (NRTL) activity coefficient model to correlate the acquired data. The findings indicated that the models showed strong concurrence with the empirical data. The binary mixture displays a near-azeotropic phenomenon when the mole fraction of R152a is below 0.65. The azeotropic point is fall within the experimental temperature range when the R152a liquid-phase has a mole fraction between 0.3069 and 0.4104. [ABSTRACT FROM AUTHOR]