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.     

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.     

Subcooled liquid density measurements and PvT measurements in the vapor phase for 3,3,3-trifluoroprop-1-ene (R1243zf)

The fluorinated propene isomer R1243zf (3,3,3-trifluoroprop-1-ene, CF₃CFCH₂, CAS number 677-21-4) is a potential alternative refrigerant with short atmospheric lifetime, low-GWP, and low acute toxicity; however, because of its flammability it is being considered primarily as a component in blends. In this paper, 302 subcooled liquid density data and 101 vapor phase PvT data are presented. The subcooled liquid density data are measured for eight isotherms, evenly separated approximately from 283 K to 353 K, for pressures from close to saturation to 35 MPa and the vapor phase PvT data are measured for six isochores for temperatures approximately from 278 K to 368 K and for pressures approximately from 260 kPa to 912 kPa. In addition, a saturated liquid density correlation, a Tait correlation for the subcooled liquid density data, and a Martin–Hou Equation of State for the vapor phase PvT data are presented.     

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.     

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.     

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.     

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.     

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.     

Condensation heat transfer and two-phase frictional pressure drop in a single minichannel with R1234ze(E) and other refrigerants

R1234ze(E), trans-1, 3, 3, 3-tetrafluoropropene, is a fluorinated propene isomer which may be a substitute of R134a for refrigeration applications. R1234ze(E) has a much lower GWP_100-years than that of R134a. In this paper, the local heat transfer coefficient during condensation of R1234ze(E) is investigated in a single minichannel, horizontally arranged, with hydraulic diameter equal to 0.96 mm. Since the saturation temperature drop directly affects the heat transfer rate, the pressure drop during adiabatic two phase flow of R1234ze(E) is also measured. Predictive models are assessed both for condensation heat transfer and pressure drop. A comparative analysis is carried out among several fluids (R1234ze(E), R32, R134a and R1234yf) starting from experimental data collected at the same conditions and using the Performance Evaluation Criteria (PEC) named Penalty Factor (PF) and Total Temperature Penalization (TTP) to rank the tested refrigerants in forced convective condensation.     

Equation of State for the Thermodynamic Properties of <Emphasis Type="Italic">trans</Emphasis>-1,3,3,3-Tetrafluoropropene [R-1234ze(E)]

An equation of state for the calculation of the thermodynamic properties of the hydrofluoroolefin refrigerant R-1234ze(E) is presented. The equation of state (EOS) is expressed in terms of the Helmholtz energy as a function of temperature and density. The formulation can be used for the calculation of all thermodynamic properties through the use of derivatives of the Helmholtz energy. Comparisons to experimental data are given to establish the uncertainty of the EOS. The equation of state is valid from the triple point (169 K) to 420 K, with pressures to 100 MPa. The uncertainty in density in the liquid and vapor phases is 0.1 % from 200 K to 420 K at all pressures. The uncertainty increases outside of this temperature region and in the critical region. In the gaseous phase, speeds of sound can be calculated with an uncertainty of 0.05 %. In the liquid phase, the uncertainty in speed of sound increases to 0.1 %. The estimated uncertainty for liquid heat capacities is 5 %. The uncertainty in vapor pressure is 0.1 %.     

Liquid Thermal Conductivity of Ternary Mixtures of Difluoromethane (R32), Pentafluoroethane (R125), and 1,1,1,2-Tetrafluoroethane (R134a)1

The thermal conductivities of ternary refrigerant mixtures of difluoromethane (R32), pentafluoroethane (R125), and 1,1,1,2-tetrafluoroethane (R134a) in the liquid phase have been measured by the transient hot-wire method with one bare platinum wire. The experiments were performed in the temperature range of 233 to 323 K and in the pressure range of 2 to 20 MPa at various compositions. The measured data are correlated as a function of temperature, pressure, and composition. From the correlation, we can calculate the thermal conductivity of pure refrigerants and their binary or ternary refrigerant mixtures. The uncertainty of the measurements is estimated to be ±2%.     

Measurements of the viscosities of saturated and compressed fluid 1-chloro-1,2,2,2-tetrafluoroethane (R124) and pentafluoroethane (R125) at temperatures between 120 and 420 K

The shear viscosities of saturated and compressed fluid 1-chloro-l,2,2,2-tetrafluoroethane (R124) and pentafluoroethane (R125) have been measured with two torsional crystal viscometers at temperatures between 120 and 420 K and at pressures up to 50 MPa. At small molar volumes, the fluidity (reciprocal viscosity) increases linearly with molar volume at fixed temperature and weakly with temperature at fixed volume. We have described this behavior with simple empirical equations and have compared the data of Shankland and of Ripple with them. The data of Ripple are in good agreement with our data for both fluids.     

(1-x)Pb(Fe2/3W1/3)O3-xPb(Mg1/2W1/2)O3多铁性材料的有序结构及磁性能

以无机盐为前驱体,利用溶胶-凝胶法固溶合成了(1-x)Pb(Fe2/3W1/3)O3-xPb(Mg1/2W1/2)O3多铁性固溶体.XRD分析表明,在0≤x≤1.0的掺杂范围内,700℃煅烧所得产物都具有钙钛矿结构;x=0时得到的纯Pb(Fe2/3W1/3)O3为长程无序结构,x=1.0时可获得完全有序的纯Pb(Mg1/2W1/2)O3相,其单胞为Pb(Fe2/3W1/3)O3单胞的2倍;当0相似文献   

Compressed Liquid Densities and Helmholtz Energy Equation of State for Fluoroethane (R161)

In this study, compressed liquid densities of Fluoroethane (R161, CAS No. 353-36-6) were measured using a high-pressure vibrating-tube densimeter over the temperature range from (283 to 363) K with pressures up to 100 MPa. A Helmholtz energy equation of state for R161 was developed from these density measurements and other experimental thermodynamic property data from the literature. The formulation is valid for temperatures from the triple point temperature of 130 K to 420 K with pressures up to 100 MPa. The approximate uncertainties of properties calculated with the new equation of state are estimated to be 0.25 % in density, 0.2 % in saturated liquid density between 230 K and 320 K, and 0.2 % in vapor pressure below 350 K. Deviations in the critical region are higher for all properties. The extrapolation behavior of the new formulation at high temperatures and high pressures is reasonable.     

Structural and Dielectric Properties of ZnO Added (Na_(1/2)Bi_(1/2))TiO_3 Ceramics

Structural and dielectric properties of polycrystalline samples of lead-free(1-x)(Na1/2Bi1/2)TiO3-xZnO,prepared using a high-temperature solid-state reaction method,were investigated in the composition range of 0≤x≤0.10.Rietveld analyses of X-ray diffraction data indicated the formation of a single-phase hexagonal structure with R3c symmetry.Williamson-Hall approach was applied to estimate the apparent particle size and lattice strain of the compounds.Temperature dependence of dielectric constant showed that the addition of ZnO to(Na1/2Bi1/2)TiO3 shifted the phase transition temperature towards higher side,a property favourable for practical applications of these ceramics.Further,temperature dependent permittivity data provided low temperature coefficient of capacitance(TCC <8%) up to 100 ℃.Furthermore,a decrease in the value of dielectric loss with an increase in ZnO content was observed.     

Crystal Structure,Lattice Vibrational Characteristic,and Dielectric Property of Nd(Mg_(1/2)Sn_(1/2))O_3 Ceramic

正Nd(Mg_(1/2)Sn_(1/2))O_3(NMS)ceramic was synthesized using a conventional solid-state reaction method.Crystal structure and morphology were investigated through X-ray diffraction(XRD)and scanning electron micrograph(SEM)technologies,respectively.Lattice vibrational modes were     

Pb（Mg_（1／2）W_（1／2））O_3－PbTiO_3－PbZrO_3陶

研究了Ｐｂ（Ｍｇ＿（１／２）Ｗ＿（１／２））Ｏ＿３－ＰｂＴｉＯ＿３－ＰｂＺｒＯ＿３陶瓷的化学不均匀性和介电行为。ＥＤＳ分析得到：体系中存在富Ｗ和富Ｚｒ、Ｔｉ的两相，平均分子式为：Ⅰ相（富Ｗ相）：Ｐｂ（Ｍｇ＿（０．２７０）Ｗ＿（０．３６７）Ｔｉ＿（０．１７８）Ｚｒ＿（０．１８２））Ｏ＿（３．０９１）；Ⅱ相（富Ｚｒ、Ｔｉ相）：Ｐｂ（Ｍｇ＿（０．１０９）Ｗ＿（０．１８７）Ｔｉ＿（０．２０４）Ｚｒ＿（０．３４０）Ｏ＿（２．７５８）。两相居里点分别为：Ｔ＿（ｃＩ）＜－６５℃，Ｔ＿（ｃＩ）＝１０５℃，图像处理得到两相的面积比为：Ｓ＿Ⅰ＝６８．６４％，Ｓ＿Ⅱ＝３１．３６％。按３－３模型复合，得到两相体积比为：７６％、２４％。复合相的介电性能符合Ｘ７Ｒ要求，｜ＴＣＣ｜≤１２％，且介－温曲线与原材料有相同的规律。     

Synthesis and electrical properties of (Bi(1/2)Na(1/2))TiO3 (BNT) ferroelectric thin films by liquid sprayed mist chemical vapor deposition technique

This study aims to synthesize lead-free ferroelectric material, (Bi(1/2)Na(1/2))TiO3 using the Liquid Sprayed Mist Chemical Vapor Deposition (LSMCVD) technique. The mist of precursor solution was vaporized and deposited on two different substrates of Si(100) and (111)Pt/TiO2/SiO2/Si(100) in an oxygen atmosphere. The deposition temperature and time were varied in the range of 400-600 degrees C and 30-90 min. (Bi(1/2)Na(1/2))TiO3 thin film had preferred orientations of (110). The thickness of the thin film deposited was 35-162 nm. The remnant polarization (2Pr) and the dielectric constant were 4.6-16.8 microC/cm2, 325-350, respectively.