Experimental liquid densities of cis-1,3,3,3-tetrafluoroprop-1-ene (R1234ze(Z)) and trans-1-chloro-3,3,3-trifluoropropene (R1233zd(E))

In this work, liquid phase densities of two fourth generation refrigerants, cis-1,3,3,3-tetrafluoroprop-1-ene R1234ze(Z) and trans-1-chloro-3,3,3-trifluoropropene R1233zd(E), are measured. The densities have been measured using a vibrating tube densimeter over the temperature range from 273.15 K to 333.15 K for pressures up to 30 MPa. For both fluids, the expanded uncertainty at a confidence level of 95% in the density measurements is estimated to be 0.07% over the entire T–p range measured.     

Compressed liquid speed of sound measurements of cis-1,3,3,3-tetrafluoroprop-1-ene (R1234ze(Z))

In this paper, 38 speed of sound measurements in the compressed liquid phase of a high purity sample of the novel alternative working fluid cis-1,3,3,3-tetrafluoroprop-1-ene (R-1234ze(Z)) are reported along five isotherms, ranging from 273.15 K to 333.15 K for pressures up to 25 MPa. The experimental technique is based on a double pulse-echo method resulting in an expanded uncertainty less than 0.05% at the 95% confidence level over the entire thermodynamic space.     

Measurements and Correlations of cis-1,3,3,3-Tetrafluoroprop-1-ene (R1234ze(Z)) Saturation Pressure

cis-1,3,3,3-Tetrafluoroprop-1-ene (R1234ze(Z)) is being investigated as a working fluid possessing a low global warming potential (GWP) for high-temperature heat pumping applications, organic Rankine cycles, and air-conditioning and refrigeration applications, and as a potential solvent, propellant, and foam blowing agent. Its GWP is less than one. The open literature contains a total of 79 vapor–pressure data from three sources and the critical state properties from a single source. The current paper provides 64 vapor–pressure data from two different laboratories over the temperature range from 238.13 K to 372.61 K. These data are regressed using Wagner and extended Antoine vapor–pressure correlations and then compared to the existing open literature data and correlations. The normal-boiling-point temperature and acentric factor for R1234ze(Z) are estimated to be 282.73 K and 0.3257, respectively.     

Measurements and Correlations of cis-1,3,3,3-Tetrafluoroprop-1-ene (R1234ze(Z)) Subcooled Liquid Density and Vapor-Phase PvT

22 182 compressed liquid density data and 98 vapor-phase PvT data for cis-1,3,3,3-tetrafluoroprop-1-ene (R1234ze(Z)) are presented. The compressed liquid density data are for nine isotherms evenly spaced approximately from 283 K to 363 K for pressures from close to saturation to 35 MPa, and the vapor-phase PvT data are for seven isochores for temperatures approximately from 303 K to 375 K for pressures approximately from 82 kPa to 436 kPa. In addition, a saturated liquid density correlation, a Tait correlation for the compressed liquid density data, and a Martin–Hou equation of state for the vapor-phase PvT data are presented.     

Experimental measurement of vapor-liquid equilibrium for (trans-1,3,3,3-tetrafluoropropene (R1234ze(E)) + propane (R290))

The VLE data for the binary system of R1234ze(E) + R290 were measured with a recirculation method at four temperatures (258.150, 263.150, 273.150 and 283.150 K). The measured uncertainties of the temperature, pressure, and compositions are ±5 mK, ±0.0005 MPa, and ±0.005, respectively. All the experimental data were correlated by the Peng-Robinson (PR) EoS with the Huron-Vidal (HV) mixing rule involving the non-random two-liquid (NRTL) activity coefficient (PR-HV-NRTL) model. Azeotropic behavior can be found at the measured temperature range.     

R1234yf and R1234ze(E) as low-GWP refrigerants for residential heat pump water heaters

Owing to the growing concerns about the relatively high global warming potential (GWP) of current refrigerants, a serious effort is in progress to find lower-GWP substitutes. The hydrofluoroolefin (HFO)-based refrigerants R1234yf and R1234ze(E) are being considered for use in multiple heating, ventilation, air conditioning, and refrigeration applications because of their very low GWP. A study was conducted to model a residential heat pump water heater using these HFOs. A system model was calibrated using experimental data and the calibrated model was used to evaluate the potential of HFOs to replace R134a. A series of parametric analyses were used to investigate the impacts of condenser wrap pattern, condenser tube size, evaporator size, and heat loss factor from the storage tank. It has been shown that both R1234yf and R1234ze(E) can be substituted for R134a with comparable performance and no substantial modifications to the original system. This study presents a detailed feasibility analysis for successful replacement of high-GWP refrigerants with low-GWP refrigerants with acceptable performance.     

三元混合制冷剂R32+R161+R1234yf气液相平衡实验研究

本文研究了含R1234yf的三元混合制冷剂的气液相平衡性质和模型,利用基于液相单相循环法搭建的气液相平衡实验装置,对温度范围为283.15～323.15 K的三元混合制冷工质R32+R161+R1234yf进行了实验研究,共得到45组实验数据。同时采用Peng-Robinson-Stryjek-Vera(PRSV)状态方程结合Wong-Sandler(WS)混合法则和Non-Random Two-Liquid(NRTL)活度系数模型,在前期工作得到的二元混合工质的模型参数的基础上,对三元混合工质气液相平衡性质进行推算。最后将模型推算结果与实验数据进行对比,结果表明系统压力平均绝对偏差AAD_p为0.34%,系统组分R32和R161的气相摩尔分数平均绝对偏差AAD_y_1和AAD_y_2分别为0.002和0.001。     

Miscibility performance of trans-1,3,3,3-tetrafluoroprop-1-ene and its binary blends with lubricating oil

In order to investigate the performance of R1234ze(E) and its blends with lubricating oil in refrigeration system, the miscibility should be well understood firstly. The critical miscibility temperature (T_CMT) data of different mass fraction of R1234ze(E) and its blends (R600a, R32) with lubricating oils (a 3GS naphthenic mineral oil and polyol ester (POE) oil) were measured and analyzed at temperature ranging from 220.15 to 310.15 K in this paper. The miscibility data were correlated with a Modified Element Contribution Evaluation Method and an evaluation equation, which was proposed to predict the miscibility of the binary blends. It was concluded that R600a promoted the miscibility of R1234ze(E)/R600a with mineral oil while R1234ze(E) blocked it. For the mixed solution of R1234ze(E)/R32 with POE oil, the more R32 had the better miscibility shown, while the more R1234ze(E) was the worse miscibility performed.     

New Fundamental Equations of State with a Common Functional Form for 2,3,3,3-Tetrafluoropropene (R-1234yf) and <Emphasis Type="Italic">trans</Emphasis>-1,3,3,3-Tetrafluoropropene (R-1234ze(E))

New fundamental equations of state explicit in the Helmholtz energy with a common functional form are presented for 2,3,3,3-tetrafluoropropene (R-1234yf) and trans-1,3,3,3-tetrafluoropropene (R-1234ze(E)). The independent variables of the equations of state are the temperature and density. The equations of state are based on reliable experimental data for the vapor pressure, density, heat capacities, and speed of sound. The equation for R-1234yf covers temperatures between 240 K and 400 K for pressures up to 40 MPa with uncertainties of 0.1 % in liquid density, 0.3 % in vapor density, 2 % in liquid heat capacities, 0.05 % in the vapor-phase speed of sound, and 0.1 % in vapor pressure. The equation for R-1234ze(E) is valid for temperatures from 240 K to 420 K and for pressures up to 15 MPa with uncertainties of 0.1 % in liquid density, 0.2 % in vapor density, 3 % in liquid heat capacities, 0.05 % in the vapor-phase speed of sound, and 0.1 % in vapor pressure. Both equations exhibit reasonable behavior in extrapolated regions outside the range of the experimental data.     

Theoretical energy performance evaluation of different single stage vapour compression refrigeration configurations using R1234yf and R1234ze(E) as working fluids

R1234yf and R1234ze(E) have been proposed as alternatives for R134a in order to work with low GWP refrigerants, but this replacement results generally in a decrease of the performance. For this reason, it is interesting to explore ways to improve the system performance using these refrigerants. In this paper, a comparative study in terms of energy performance of different single stage vapour compression configurations using R1234yf and R1234ze(E) as working fluids has been carried out. The most efficient configuration is the one which uses an expander or an ejector as expansion device. On the other hand, using an internal heat exchanger in a cycle which replaces the expansion valve by an expander or an ejector could produce a detrimental effect on the COP. However, for all the configurations the introduction of an internal heat exchanger produces a significant increment on the cooling capacity.     

Energy performance evaluation of R1234yf,R1234ze(E), R600a,R290 and R152a as low-GWP R134a alternatives

In 2014, the Directive 517/2014 was introduced by European Parliament to reduce the use of high-GWP greenhouse gases in the European area in order to limit global climate change in accordance with the objectives marked by the EU Research and Innovation programme Horizon 2020. These restrictions affect the large majority of artificial refrigerants among which R134a is included due to its relatively high GWP₁₀₀ (1301). The widely used of R134a in the refrigeration and air conditioning fields reveals the need to identify new low-GWP alternatives. Accordingly, in this work five low-GWP R134a possible choices have been tested and compared in an identical refrigerating facility equipped with a hermetic compressor, under the same operating conditions.The refrigerants used in this analysis are: R290 and R600a (HCs); R134a and R152a (HFCs), and finally, R1234yf and R1234ze(E) (HFOs). All of them have been assayed without changes in the facility, that is, as direct drop-ins. The results obtained from the experimental tests are presented and commented in this work from the energetic point of view.     

Ideal-Gas Heat Capacity for 2,3,3,3-Tetrafluoropropene (HFO-1234yf) Determined from Speed-of-Sound Measurements

The isobaric ideal-gas heat capacity for HFO-1234yf, which is expected to be one of the best alternative refrigerants for HFC-134a, was determined on the basis of speed-of-sound measurements in the gaseous phase. The speed of sound was measured by means of the acoustic resonance method using a spherical cavity. The resonance frequency in the spherical cavity containing the sample gas was measured to determine the speed of sound. After correcting for some effects such as the thermal boundary layer and deformation of the cavity on the resonance frequency, the speed of sound was obtained with a relative uncertainty of 0.01 %. Using the measured speed-of-sound data, the acoustic-virial equation was formulated and the isobaric ideal-gas heat capacity was determined with a relative uncertainty of 0.1 %. A temperature correlation function of the isobaric ideal-gas heat capacity for HFO-1234yf was also developed.     

新型制冷剂R1234ze(E)及其混合工质研究进展

低GWP值制冷剂R1234ze(E)(trans-1,3,3,3-tetrafluoropropene)作为R134a较为理想的替代品而被关注,但其单一成分的热力学性能和传输特性并不理想,在R1234ze(E)中混入R32成分可以有效改善其热力学性能。本文概述了低GWP值工质R1234ze(E)及其与R32混合物的热物性特征、传输特性及系统运行性能方面的研究现状,并与目前常用的制冷工质进行比较分析,指出R1234ze(E)与R32混合工质有望成为新型低GWP值替代工质。     

Exergy analysis of R1234yf and R1234ze as R134a replacements in a two evaporator vapour compression refrigeration system

Exergy analysis is a useful way for determining the real thermodynamic losses and optimising environmental and economic performance in the systems such as vapour compression refrigeration systems. The present study deals with the exergy analysis on a two evaporator vapour compression refrigeration system using R1234yf, R1234ze and R134a as refrigerants. In the calculation of losses occurring in different system components, besides the exergy efficiency of the refrigeration cycle, a computer code was developed by using Engineering Equation Solver (EES-V9.172-3D) software package program. The effects of the evaporator and condenser temperatures on the exergy destruction and exergy efficiency of the system were investigated. R1234yf and R1234ze, which are good alternatives to R134a concerning their environmentally friendly properties and this is the most significant finding emerging from this study.     

HFO1234ze(E) vaporisation inside a Brazed Plate Heat Exchanger (BPHE): Comparison with HFC134a and HFO1234yf

This paper investigates the effects of heat flux, saturation temperature, and outlet conditions on HFO1234ze(E) boiling inside a Brazed Plate Heat Exchanger (BPHE). The effect of the heat flux on the heat transfer coefficients was remarkable. Similar consideration applies for outlet condition effects whereas the impact of saturation temperature was found to be lower. The frictional pressure drop shows a linear dependence on the refrigerant kinetic energy per unit volume. The two-phase flow boiling heat transfer coefficients were compared with a new model for refrigerant boiling inside BPHE (Longo et al., 2015): the mean absolute percentage deviation between calculated and experimental data is 7.2%. The present data points were compared with those of HFC134a and HFO1234yf previously measured inside the same BPHE under the same operating conditions: HFO1234ze(E) exhibits heat transfer coefficients very similar to HFC134a and HFO1234yf and frictional pressure drops slightly higher than HFC134a and HFO1234yf.     

Comparative performance analysis of the low GWP refrigerants HFO1234yf,HFO1234ze(E) and HC600a inside a roll-bond evaporator

This paper presents the comparative performance analysis of the low GWP refrigerants HFO1234yf, HFO1234ze(E) and HC600a inside a commercial roll-bond evaporator for household refrigerators. The vaporisation performances were evaluated at two evaporation temperatures, −15 and −20 °C, and different refrigerant mass flow rates and compared with those of the traditional refrigerant for domestic refrigeration HFC134a. The performance analysis was carried out using both thermocouples installed on the rear side of the roll-bond evaporator and an IR thermo-camera. Each of the low GWP refrigerants tested can be considered a good substitute for HFC134a, provided that the compressor displacement is adjusted to deliver the proper refrigerant mass flow rate. Only HFO1234yf exhibits performance similar to HFC134a at the same mass flow rate, therefore it can be considered a direct drop-in substitute for HFC134a.     

R1234ze(E)在多元醇脂油中溶解度的实验研究

R1234ze(E)(1,1,1,3-四氟丙烯)是当下具有较强替代潜能的环保制冷剂之一。本文搭建了溶解度测试实验系统,对R1234ze(E)在两种多元醇脂油中的溶解度进行测试,测试的温度范围为40～80℃,压力范围为0.123～0.360 MPa。采用PR状态方程和MHV2混合规则及NRTL活度系数模型对实验结果进行关联计算,得到不同温度下的交互系数及计算值与实验值的平均相对误差。结果表明:R1234ze(E)在两种多元醇脂油中的溶解度均随着温度的升高而降低,且R1234ze(E)在两种多元醇脂油中的平衡压力与溶解度之间存在立方函数关系。在两种多元醇酯油中,计算值与实验值的平均相对误差分别为1.68%和1.11%,可较好的描述R1234ze(E)在两种多元醇酯油中的相平衡行为。     

微圆管内R1234ze(E)流动沸腾的环状流特性模拟研究

本文建立了制冷剂R1234ze(E)在微圆管内流动沸腾过程中的环状流模型,对传热和气液两相流动压降进行了模拟研究。综合考虑重力、表面张力及气液界面剪切力的影响,模拟分析了周向液膜不均匀分布特性及该特性对流动与换热的影响,经验证,计算结果与已有实验结果吻合较好。本文还研究了不同因素对环状流区域表面传热系数与压降的影响。模拟结果表明:在流动起始区域,截面液膜厚度的分布受重力作用影响,随着流动沸腾过程的进行,该影响作用开始减弱,且有重力作用时的环状流平均表面传热系数高于无重力作用时的环状流平均表面传热系数,随着重力加速度的增加,环状流的平均表面传热系数不断增大;随着质量流速的增大,表面传热系数与压降均随之增大;随着管径增大,表面传热系数与压降均随之减小。     

Monte Carlo Simulation of Vapor–Liquid Equilibria for Perfluoropropane (R-218) and 2,3,3,3-Tetrafluoropropene (R-1234yf)

Thermophysical properties of two refrigerants (perfluoropropane and 2,3,3,3-tetrafluoropropene) were computed using Monte Carlo methods with the OPLS-AA (Optimized Potentials for Liquid Simulations-All Atoms) forcefield. Original OPLS-AA parameters were extended to include an F atom attached to a double bond in 2,3,3,3-tetrafluoropropene and modified to produce the correct stationary geometry for this compound. The results of the simulations for critical parameters, saturated densities, saturated pressures, liquid densities, and vaporization enthalpies are in good agreement with available experimental data and equation of state models. Systematic deviations between the experimental data and the predicted values were observed for liquid densities and saturated pressures, suggesting that further refinement of forcefield parameters that can lead to better accuracy may be possible.     

Flow boiling of non-azeotropic mixture R32/R1234ze(E) in horizontal microfin tubes

Flow boiling of a potential refrigerant R32/R1234ze(E) in a horizontal microfin tube of 5.21 mm inner diameter is experimentally investigated. The heat transfer coefficient (HTC) and pressure drop are measured at a saturation temperature of 10 °C, heat fluxes of 10 and 15 kW m^?2, and mass velocities from 150 to 400 kg m^?2 s^?1. The HTC of R1234ze(E) is lower than that of R32. Degradation in the HTC of the R32/R1234ze(E) mixture is significant; the HTC is even lower than that of R1234ze(E). The HTC is minimized at the composition 0.2/0.8 by mass, where the temperature glide and the mass fraction distribution are maximized. A predicting correlation based on Momoki et al. (1995) associated with the correction methods of Thome (1981) to consider the mass transfer resistance and Stephan (1992) to consider the additionally required sensible heat is proposed and validated with the experimental results.