Language：English   Publishing type：Research paper (scientific journal)  

Measurements of the thermodynamic properties of HFO-1234yf were conducted. The critical temperature TC, critical density ρC, and critical pressure PC, were measured by the visual observation of the meniscus disappearance, and were determined to be 367.85 ± 0.01 K, 478 ± 3 kg/m3, and 3382 ± 3 kPa, respectively. Vapor pressures were measured by a batch-type calorimeter with a metal-bellows in the temperature range from 310 K to 360 K and correlated by the Wagner-type equation. Surface tensions were measured by the differential capillary-rise method in the temperature range from 273 K to 340 K and correlated by the van der-Waals type equation. The acentric factor was determined to be 0.280 with the vapor pressure correlation. Based on the critical parameters and acentric factor, saturated vapor and liquid densities were estimated by the Peng-Robinson equation and the Hankinson-Thomson equation, respectively. The heat of vaporization was also calculated from the Clausius-Clapeyron equation. © 2009 Elsevier Ltd and IIR.

DOI： 10.1016/j.ijrefrig.2009.10.003

Publisher：Journal of Molecular Liquids  

This study performed surface tension measurements assisted by molecular simulations for new candidate refrigerants R1132(E) and its isomer R1132a, which exhibit extremely low global warming potentials. Because the measured saturation density required for the surface tension measurement by the differential capillary rise method is insufficient at low temperatures, the density data was extrapolated by molecular simulations. In the process, quantum chemical and molecular dynamics simulations were performed to reproduce the vapor–liquid equilibrium state, and the accuracy of the obtained molecular force fields was verified by comparing them with the measured data. Based on the obtained surface tension data, validated temperature correlation equations were proposed for R1132(E) and R1132a, respectively, validated in the temperature range from 209 K to 225 K. Furthermore, their parachors, which relate surface tension to saturation density, were determined from the above data as 116.1 and 116.7 for R1132(E) and R1132a, respectively.

DOI： 10.1016/j.molliq.2024.125262

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Publisher：International Journal of Thermophysics  

PVTx properties of 0.80 mass fraction HFO1123 + 0.20 mass fraction R290 and 0.65 mass fraction HFO1123 + 0.35 mass fraction R290 refrigerant blends were measured in the temperature range from 300 K to 400 K and at pressures up to 6.9 MPa by the isochoric method along 6 isochores for each blend including the vapor and liquid phases. The expanded uncertainties in temperature and pressure are estimated to be 5 mK and 1.0 kPa (k = 2). The relative expanded uncertainties in density and mass fraction are estimated to be 0.15% and 0.0005 (k = 2), respectively. Saturated densities of these blends were directly measured in the temperature range between 319 K and 342 K by the visual observation of the meniscus disappearance, and also determined from the inflection points of the PVTx isochore-lines. Finally, the critical points of the blends were determined by the consideration of the meniscus disappearing level as well as the intensity of the critical opalescence as Tc = 334.91 ± 0.01 K, ρc = 402 ± 3 kg·m−3 and Pc = 4392 ± 3 kPa for 0.80 mass fraction HFO1123 + 0.20 mass fraction R290, and Tc = 340.94 ± 0.02 K, ρc = 357 ± 3 kg·m−3 and Pc = 4429 ± 5 kPa for 0.65 mass fraction HFO1123 + 0.35 mass fraction R290. A Helmholtz energy equation of state (EOS) was compared with the experimental data, and is in good agreement with the obtained PVTx property data with an absolute average deviation (AAD) of 1.1% for 0.80 mass fraction HFO1123 + 0.20 mass fraction R290, and that of 0.7% for 0.65 mass fraction HFO1123 + 0.35 mass fraction R290 in density. In addition, vapor-liquid equilibrium data of HFO1123 + R290 blends were obtained from 263 K to 323 K based on the recirculation method. A mixing parameter of a simple cubic EOS was determined, and the EOS represents the VLE data with an AAD of 0.73% in pressure and 0.010 mol·mol−1 in mole fraction.

DOI： 10.1007/s10765-024-03330-6

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Publishing type：Research paper (scientific journal)   Publisher：International Journal of Refrigeration  

This study presents a comparative energy, exergy, and life cycle climate performance (LCCP) analysis of various refrigerants in a cascade refrigeration system (CRS). The refrigerants analyzed in the low-temperature cycle (LTC) include R-23, R-116, R-41, R-170, R-1150, and R-1132a whereas high-temperature cycle (HTC) utilizes R-404A, R-455A, R-454C, R-459B, R-161, R-290, R-1270, and R-1234yf. For the first time for CRS, LCCP analysis is conducted and fourth generation low GWP and less flammable prospective refrigerants R-1132a, R-455A, R-454C, R-459B are analyzed. The study aims to find a refrigerant pair that outperforms R-23/R-404A in terms of thermodynamic efficiency while also considering environmental impact and safety considerations. Among the 48 refrigerant groups analyzed, the study reveals that R-170/R-161 and R-41/R-161 demonstrate superior performance in terms of thermodynamic efficiency and environmental impact assessment whereas the largest exergy destruction components are HTC/LTC compressors. However, if flammability is a major concern, the recommended refrigerant pair is R-1132a/R-1234yf, as it is a suitable alternative in terms of safety considerations while still maintaining favorable thermodynamic and environmental performance.

DOI： 10.1016/j.ijrefrig.2023.12.020

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Publisher：International Journal of Thermophysics  

Vapor–liquid equilibrium (VLE) of binary refrigerant blends, HFO1123 + CF3I and HFC125 + CF3I, were measured at temperature range from 263 to 323 K by the recirculation method. A sample was filled into an equilibrium cell of the experimental apparatus equipped with optical windows in the vapor–liquid equilibrium condition, and the saturated vapor and liquid were extracted from each phase in small quantities. The compositions of the samples were measured by a gas chromatograph with a thermal conductivity detector and a Porapak-Q column. The expanded uncertainties in temperature, pressure, and composition are estimated to be 10 mK, 3.0 kPa, and 0.007 mol·mol−1, respectively. Based on the experimental data, mixing parameters of a cubic equation of state (PR EOS) and Helmholtz energy EOSs were determined. The VLE behavior (temperature, pressure, and composition relation) calculated from the PR EOS and the Helmholtz energy EOSs show good agreement with each other. The PR EOS reasonably represents the VLE data with an absolute average deviation (AAD) of 1.8% for HFO1123 + CF3I and that of 1.1% for HFC125 + CF3I in pressure, and with an AAD of 0.012 mol·mol−1 in mole fraction for both mixtures. In addition, PVTx properties of HFO1123 + CF3I and HFC125 + CF3I blends were measured from 300 to 400 K and at pressures up to 6.9 MPa by the isochoric method. The expanded uncertainties in temperature and pressure are estimated to be 5 mK and 1.0 kPa (k = 2). The relative expanded uncertainties in density and mass fraction are estimated to be 0.0015 and 0.0005 (k = 2), respectively. The Helmholtz energy EOSs with the mixing parameters determined on the basis of the VLE data were compared with the experimental PVTx property data, and the EOSs represent them in the vapor phase except for the isochores near the critical density with an AAD of 0.9% in density.

DOI： 10.1007/s10765-023-03286-z

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：International Journal of Thermophysics  

R-1132a is increasingly being considered as a low global warming potential component in alternative mixtures to R-23 in specialized low temperature and ultra-low temperature refrigeration systems. Though the thermodynamic properties of R-1132a were investigated in several studies up to 2018, reinvestigations have been carried out in recent years. In order to contribute toward these renewed measurements, the critical parameters of R-1132a were experimentally re-determined. Thirty-two vapor pressures from 240 K to the critical temperature, fifteen saturated vapor and six saturated liquid densities above 254 K and the PvT properties in both the vapor phase (98 points) and liquid phase (34 points) from densities of 50 kg·m−3 to 760 kg·m−3 were also measured. Specific correlations for each of these properties were optimized and compared to previously available data from the literature. Additionally, the Peng–Robinson equation of state was used to represent the aforementioned properties and further utilized to determine the enthalpy and entropy of R-1132a.

DOI： 10.1007/s10765-023-03184-4

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Publishing type：Research paper (scientific journal)   Publisher：International Journal of Thermophysics  

A new isochoric apparatus was developed for measuring PvT properties of refrigerants from 240 K to 410 K. This temperature range extends measurements below ambient (~ 300 K) and overlaps with the range of other isochoric apparatuses in NEXT-RP centre of I2CNER, Kyushu University. PvT properties of four refrigerants (1,1,1,2-tetrafluoroethane, R-134a; pentafluoroethane, R-125; trifluoromethane, R-23 and 2,3,3,3-tetrafluoropropene, R-1234yf) were measured for the inner volume calculation and validation exercise. Vapour pressures of 1,1-difluoroethene (R-1132a) were measured between 240 K and 296 K (14 data points). All property measurements were conducted for heating up and cooling down phases. The expanded uncertainty values of temperature, pressure and density using the new isochoric apparatus are U(T) = 10 mK, U(p) = 1 kPa and Ur(ρ) = 0.002, respectively, where the coverage of 2 was adopted for 95% confident levels. The measured vapour pressures were fitted using Wagner-type and Antoine-type equations and compared with the published data.

DOI： 10.1007/s10765-023-03167-5

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Language：English   Publisher：Japan Society of Refrigerating and Air Conditioning Engineers  

<p><b> </b>R 473A is an emerging four-component refrigerant blend for replacing high GWP and flammable refrigerants currently used for low temperature applications. Since limited prior publications on the thermodynamic properties of R 473A are available, the initial investigation of its vapor phase <i>pvT</i> properties were carried out and are presented here. The <i>pvT</i> properties were measured using two separate isochoric apparatus for the temperature range of 270 K to 400 K, density range of 43 kg·m^-3 to 210 kg·m^-3and at pressures below 7 MPa. The virial equation of state was used to verify the measured properties. The linearized virial equation was used to determine the second and third virial coefficients. This method provided an absolute average deviation in pressure and density of 0.29% and 0.38%, respectively. The measured properties were all within 1% deviations which signify the accuracy of the results and the potential for them to be used as preliminary data for developing a more accurate representation of R 473A properties through equations of state.</p>

DOI： 10.11322/tjsrae.22-24dt_em

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

Mixing R13I1 with flammable or weakly flammable refrigerants is an approach to reduce both their flammability and global warming potential (GWP); however, thermodynamic property data of mixtures containing R13I1 are currently scarce. In this work, experimental measurements were performed for the (p, ρ, T) behavior in the vapor-phase of R32 + R13I1, R125 + R13I1, and R32 + R125 + R13I1 mixtures. The measurements were made at temperatures from 300 K to 400 K and pressures up to 6.3 MPa, and 44 data points were obtained for the R32 + R13I1 mixture and 25 data points for the R125 + R13I1 mixture. For the ternary mixture, 25 data points were obtained at the composition of R466A (R32:R125:R13I1 = 49:11.5:39.5 mass %). The validity of the experimental data was verified by comparing to the virial equation of state generalized for nonpolar or weakly polar fluids based on the corresponding states principle. The comparison showed that deviations between the experimental and calculated pressures are generally minor and less scattered; this suggests that the (p, ρ, T) data obtained in this work are reasonable in terms of the law of corresponding states.

DOI： 10.1007/s10765-022-03080-3

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Other Link： https://link.springer.com/article/10.1007/s10765-022-03080-3/fulltext.html

Publishing type：Research paper (scientific journal)   Publisher：Elsevier {BV}  

PvT properties, saturated densities, and critical parameters of R1132(E) were measured with two kinds of experimental apparatus. Along eight isochores between 65 and 832 kg m−3, PvT property measurements were carried out in the temperature range from 310 to 400 K and at pressures up to 6.5 MPa by the isochoric method. The saturated-vapor and saturated-liquid densities were determined by the visual observation of meniscus disappearance and by the break point of the PvT property isochores in the temperature range from 304 K to the critical temperature and in the density range from 65 to 833 kg m−3. The critical temperature and density were also determined as Tc = 348.82 ± 0.01 K and ρc = 438 ± 3 kg m−3 on the basis of the meniscus disappearing level as well as the intensity of the critical opalescence.

DOI： 10.1016/j.ijrefrig.2022.05.012

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Publishing type：Research paper (scientific journal)   Publisher：Journal of Chemical and Engineering Data  

Measurements of PvT properties, saturated pressures, saturated densities, and critical parameters were carried out for R-13I1 (trifluoroiodomethane; CF3I). Forty-seven PvT property data in the one-phase region along seven isochores for R-13I1 were obtained in the temperatures between 310 and 405 K, pressures up to 6392 kPa, and densities between 48 and 1784 kg·m-3using the isochoric method. Thirty-seven saturation pressure data for R-13I1 were obtained in the temperatures between 240 K and the critical temperature and pressures between 58 kPa and the critical pressure. Twenty-six saturated density data for R-13I1 were obtained by the observation of meniscus disappearance and the inflection points of the isochore in the densities between 48 and 1784 kg·m-3. On the basis of these measurements, the critical temperature, critical density (critical molar volume), and critical pressure of R-13I1 were determined as Tc= 396.495 ± 0.010 K (with a coverage factor, k = 2), ρc= 865 ± 5 kg·m-3(vc= 226.5 ± 1.3 cm3·mol-1) (bracketed interval), and Pc= 3971 ± 3 kPa (with a coverage factor, k = 2), respectively. Moreover, a correlation for the saturation pressure and correlations for the vapor liquid coexistence curve were established by optimization techniques.

DOI： 10.1021/acs.jced.2c00182

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Publishing type：Research paper (scientific journal)   Publisher：International Journal of Refrigeration  

The authors regret the typo error of one data at T=320.11 K in Table 3. The corrected table is as follow; No other error is found. All figures and equations in this article were made based on the correct data set. The authors would like to apologise for any inconvenience caused.

DOI： 10.1016/j.ijrefrig.2021.01.027

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Publishing type：Research paper (scientific journal)   Publisher：International Journal of Refrigeration  

R1132(E) (trans-1,2-difluoroethylene, C2H2F2) is a potential next generation refrigerant to be utilized in air conditioning applications. This hydrofluoroolefin (HFO) refrigerant possesses an extremely low-GWP value below 1 and it is an excellent candidate for replacing R32 in blends such as R410A, which are subjected to local and international greenhouse gas regulations for limiting global warming. Two isochoric apparatus were used to measure the saturation pressures of R1132(E) from 240 K to its critical temperature. At the critical temperature, the critical pressure of R1132(E) was also directly measured. Twenty-four saturation pressures including the critical point were used for optimizing a Wagner-type equation representing the saturation pressure curve. The absolute average deviation of the saturation pressures of R1132(E) predicted by the model using the fitted parameters and the experimental data is 0.02%. The optimized Wagner-type equation of saturation pressures is used for determining the acentric factor of R1132(E) as 0.2433, which is further utilized for the prediction of the saturation pressures using the Peng-Robinson cubic equation of state within an absolute average deviation of 0.31%.

DOI： 10.1016/j.ijrefrig.2021.12.014

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Publishing type：Research paper (scientific journal)   Publisher：Journal of Chemical and Engineering Data  

The (p, ρ, T) behavior of a refrigerant mixture of 50.00 mass% R1234yf and 50.00 mass% R290 was measured with the isochoric method. Along the six isochores (60, 121, 305, 500, 550, and 600 kg·m-3), a total of 40 single-phase (p, ρ, T) data points were obtained at temperatures from 330 to 400 K and pressures up to 6.6 MPa. In addition, the phase boundary of this mixture was experimentally investigated by visual observation of the vapor-liquid meniscus, and a total of 17 saturated densities and the critical parameters were obtained. Additionally, five saturated densities were also determined from the inflection points of the isochores. According to the multifluid approximation approach, a thermodynamic mixture model was formulated for R1234yf/290 mixtures. The parameters of the mixture model were determined by fitting the experimental data obtained in this work and those available in the literature. Expected uncertainties (k = 2) in calculated values with the mixture model are 0.2% for bubble and dew point pressures, 0.2% for liquid densities, 0.4% for vapor densities, 1% for saturated liquid and vapor densities, and 1.5% for isochoric heat capacities in the liquid phase. The mixture model can also be applied to regions away from the fitted experimental data with reasonable accuracy because it extrapolates well to higher temperatures and pressures, and to lower temperatures.

DOI： 10.1021/acs.jced.1c00890

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Chemical Society of Japan  

Current greenhouse gas emissions suggest that keeping global temperature increase below 1.5 degrees, as espoused in the Paris Agreements will be challenging, and to do so, the achievement of carbon neutrality is of utmost importance. It is also clear that no single solution can meet the carbon neutral challenge, so it is essential for scientific research to cover a broad range of technologies and initiatives which will enable the realization of a carbon free energy system. This study details the broad, yet targeted research themes being pioneered within the International Institute for Carbon-Neutral Energy Research (I2CNER). These approaches include hydrogen materials, bio-mimetic catalysts, electrochemistry, thermal energy and absorption, carbon capture, storage and management and refrigerants. Here we outline the state of the art for this suite of technologies and detail how their deployment, alongside prudent energy policy implementation can engender a carbon neutral Japan by 2050. Recognizing that just as no single technological solution will engender carbon neutrality, no single nation can expect to achieve this goal alone. This study represents a recognition of conducive international policy agendas and is representative of interdisciplinary, international collaboration.

DOI： 10.1246/bcsj.20210323

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Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.18462/iir.HFO.2021.1023

Language：English   Publishing type：Research paper (scientific journal)  

Countermeasures for global warming have been promoted internationally. Heat pump cycles that utilize refrigerants with high global warming potential values are required to adopt the next generation refrigerants to conform to the revised Montreal Protocol. Refrigerants R410A is commonly used in the room air conditioners while it has been substituted with HFC32 in Japan; yet their global warming potential values are relatively high and are going to be phased down in the near future. On the other hand, refrigerant mixtures such as the blend of HFC32 and HFO1234yf with extremely low global warming potential can be considered as possible alternatives in compromising the flammability and the ecological tribulations. Targeting the global warming potential value of 150 or lower, the performance of HFC32/HFO1234yf (22/78 mass%) blend was evaluated using drop-in tests, and the results were compared with those of R410A and HFC32. Optimum charge amounts for these refrigerants were first evaluated, followed by the performance comparison in terms of the coefficient of performance from part- to full-load operations. The results showed that the current blend with the low global warming potential less than 150 is comparable to the targeted substitutes at part-load operations while within 83–87% of the COP using HFC32 was achievable at the full-load. The performance results from these experiments could serve as the basis for the refrigerant evaluation targeting the global warming potential 150.

DOI： 10.1080/01457632.2020.1776997

Language：English   Publishing type：Research paper (scientific journal)  

The urge to replace hydrofluorocarbons which possess high global warming potentials has taken center stage in the air conditioning industry due to both international and local policies such as the Kigali Amendment and Japan’s revised Fluorinated Gas law. This has prompted the exploration of novel refrigerants as well as their mixtures to create high performance environmentally friendly alternatives. These refrigerants can be integrated into existing systems as ‘drop in’ refrigerants, which provide a simpler and low cost substitution process to replace environmentally harmful refrigerants such as R410a. R410a is currently a widely used refrigerant in air conditioning systems, but is to be phased out of use under the Kigali Amendment by the late 2040s. Thus to compare the suitability of replacing this refrigerant with environmentally friendly ‘drop in’ alternatives, a preliminary baseline investigation on a mechanical vapor compression chiller with R410a is conducted via performance and exergy indicators. The testing procedure utilized Air Conditioning, Heating and Refrigeration Standard 551/591 which revealed an optimum charge amount of 0.70 kg with a peak performance near 88% of full capacity. The heat exchanger overall heat transfer coefficients showed varying trends, whilst the exergy destruction was as expected highest for the compressor.

DOI： 10.1080/01457632.2020.1776990

Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.18462/iir.HFO.2021.1024

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1021/acs.jced.0c00848

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10/1016/j.ijrefrig.2020.10.009

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.applthermaleng.2020.115952

Language：Others   Publishing type：Research paper (scientific journal)  

© 2020 The vapor–liquid equilibrium properties of R32/R1123 binary refrigerant mixtures were precisely determined. Such mixtures have the potential to provide a reduced global warming potential although data regarding their properties is extremely limited, especially with regard to vapor–liquid equilibrium characteristics such as boiling point and dew point pressures, for which no actual experimental data exist. The present study acquired such data by means of two recirculation type apparatuses located at different universities. One apparatus, which was used to measure data in high temperature region, is installed at Toyama Prefectural University and includes an optical cell and two circulation loops with a thermostatted liquid bath. After thermal equilibration, a part of the sample in both loops is sandwiched between two valves and mixed with helium, following which the compositions are determined using gas chromatograpy. The other apparatus, which was for lower temperature region, at Kyushu University, has a similar design. The vapor–liquid equilibrium data were obtained between 300 and 330 K using the apparatus for high temperatures and from 273 to 313 K using the apparatus for low temperatures. These data were compared with predictions from the Helmholtz-type equation of state and a systematic deviation of approximately 1&#37; was observed at low temperatures. A regression analysis using the binary interaction parameter kij for the modified Peng–Robinson equation of state more accurately reproduced the present measurement results.

DOI： 10.1016/j.ijrefrig.2020.07.005

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1007/s10765-020-02752-2

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Vapor pressures for new low-GWP refrigerants of R1233zd(E) (trans-1-chloro-3,3,3-trifluoropropene) and R1336mzz(Z) (cis-1,1,1,4,4,4-hexafluoro-2-butene) were measured by the isochoric method. Twelve vapor-pressure measurements of R1233zd(E) were obtained at temperatures between 300 and 410 K, whereas 17 vapor-pressure measurements of R1336mzz(Z) were obtained at temperatures between 290 and 410 K. Temperature was measured with a 25 ω standard platinum resistance thermometer with an aid of ITS-90, and pressure was measured with a digital quartz pressure transducer. The experimental uncertainties in temperature and pressure are estimated to be within 5 mK and 1 kPa, respectively. The experimental data were compared with the previous experimental data and equations of state. New vapor-pressure correlations of R1233zd(E) and R1336mzz(Z) have been formulated on the basis of the data obtained.

DOI： 10.1021/acs.jced.0c00239

Language：Others   Publishing type：Research paper (scientific journal)  

Copyright © 2020 American Chemical Society. In this paper, 182 pvTz data (28 data in the two-phase region and 154 data in the superheated vapor region) of mixtures containing difluoromethane (R32) and trans-1,3,3,3-tetrafluoroprop-1-ene (R1234ze(E)) are reported. The measurements were carried out along 10 isochores (0.013173, 0.039422, 0.043115, 0.046522, 0.062966, 0.068225, 0.068959, 0.110447, 0.115156, and 0.121732 m3·kg-1) in the temperature range from 263 to 373 K for 10 R32 mole fractions (0.1677, 0.2360, 0.2551, 0.4634, 0.5374, 0.6715, 0.7383, 0.7544, 0.9532, and 0.9533). The flash method with three equations of state (EoSs) was used to assess the vapor-liquid equilibrium of the binary mixture under analysis. The calculated vapor-liquid equilibrium behavior for the R32 + R1234ze(E) binary system agreed with the experimental data collected from the open literature. The vapor-phase measurements were correlated through the aforementioned EoSs and a truncated virial EoS. These pvTz points agreed with both the values provided by the EoSs and REFPROP 10.0.

DOI： 10.1021/acs.jced.9b00995

Language：Japanese   Publishing type：Research paper (scientific journal)  

Correlation Assessment and Temperature Dependence Check ofSurface Tension and Parachor for New Low-GWP Pure Refrigerants

DOI： 10.11322/tjsrae.19-36TG_EM_OA

Language：Others   Publishing type：Research paper (scientific journal)  

Copyright © 2019 American Chemical Society. This article presents the accurate surface tension measurement of cis-1-chloro-2,3,3,3-tetrafluoropropene (R1224yd(Z), (Z)-CF3CFâ• CHCl), over the temperature range 266-340 K. The measurement was performed using the differential capillary rise. The expanded uncertainty at 95&#37; confidence was estimated to be within 0.19 mN·m-1. Based on the measured data, the van der Waals-type correlation expressing the temperature dependence was obtained as σ = 57.02 (1 - T/428.69)1.265 [mN·m-1]. In addition, the parachor [PR1224yd(Z)] was determined as 207. The surface tension values predicted by Miller and Thodos (Ind. Eng. Chem. Fund., 1963, 2.1, 78), Miqueu et al. (Fluid Ph. Equilibria, 2000, 172, 169), and Di Nicola et al. (Int. J. Thermophys., 2011, 34, 2243), as well as those obtained using the parachor method, were in good agreement with the measurement data.

DOI： 10.1021/acs.jced.9b00613

Language：Others   Publishing type：Research paper (scientific journal)  

Copyright © 2019 American Chemical Society. PvT properties, vapor pressures, and saturated densities for a new low-GWP refrigerant; R1224yd(Z) (cis-1-chloro-2,3,3,3-tetrafluoropropene; CF3CF=CHCl), were measured. Forty-six PvT property data were obtained along four lower density isochores in the superheated region; 22, 48, 55, and 103 kg·m-3, and three higher density isochores in the compressed liquid region; 970, 1107, and 1197 kg·m-3 at pressures up to 6.4 MPa. Fifteen vapor pressure data were obtained in the temperature range from 310 to 410 K and at pressures up to 2393 kPa, and a vapor pressure correlation was formulated based on these vapor pressure measurements. Saturated vapor and liquid densities were directly measured by the visual observation of the vapor-liquid meniscus disappearance in the critical region, and also graphically determined by the intersections of the vapor pressure curve and the isochores of the PvT properties. In addition, the critical temperature Tc = 428.69 ± 0.02 K, the critical density ρc = 535 ± 5 kg·m-3, and the critical pressure Pc = 3331 ± 3 kPa for R1224yd(Z) were determined.

DOI： 10.1021/acs.jced.9b00374

Language：Others   Publishing type：Research paper (other academic)  

© 2019 International Institute of Refrigeration. All rights reserved. LNG (Liquefied Natural Gas) vaporizer is widely used all over the world to vaporize LNG by using seawater, etc. as a heating source. Intermediated Fluid type LNG Vaporizer (IFV) is using intermediated fluid between LNG and heating source. Propane has been used as an intermediated fluid conventionally, but new refrigerants except for propane are required because usage environment was diversified recently. In this study, refrigerants substitute for propane applicable to IFV were selected as R32 and R410A. On the basis of some experimental formula, prediction of boiling and condensation heat exchange quantity in tube bundles was also carried out and it enabled to predict actual IFV vaporization quantity with plus or minus 2 percent accuracy. The prediction demonstrated that those selected refrigerants can increase the vaporization rate with IFV from the base line of propane.

DOI： 10.18462/iir.icr.2019.1596

Language：Others   Publishing type：Research paper (other academic)  

© 2019 International Institute of Refrigeration. All rights reserved. In this work, the calculated surface tension of selected new low GWP (global warming potential) pure compound refrigerants HFO (hydro-fluoro-olefin) is presented. Molecular simulation methods are used to calculate the surface tension of R-1123 (trifluoroethylene) and of R-1234ze(E) (trans-1,3,3,3-tetrafluoroprop-1-ene), as well as densities at saturation. The results obtained by molecular simulation are compared with recent experimental data.

DOI： 10.18462/iir.icr.2019.0060

Language：English  

By a differential capillary rise method, the surface tension was measured for a new candidate of low GWP refrigerant HFO-1123. 16 points of surface tension data with a propagated uncertainty of approximately ±0.22 mN m^-1 are presented in this paper. Based on the measured data, a Van der Waals type empirical correlation was proposed for HFO-1123:
σ = 61.02 (1-T/T_crit)^1.30 [mN m^-1], where T_crit is a critical temperature of 331.7 K measured by Higashi and Akasaka. This empirical correlation agrees with the measured surface tension data at temperatures from 267 K to 304 K.

DOI： 10.11322/tjsrae.18-31

Language：English  

Language：English   Publishing type：Research paper (scientific journal)  

Measurements of PvT properties, saturated densities, and critical parameters were carried out for a low-GWP refrigerant: 3,3,3-trifluoropropene (HFO1243zf, CF₃CH=CH₂). Seventy-five PvT property data points along seven isochores around the critical point were obtained in the temperature range from 328 to 430 K, in the density range between 50 and 899 kg m^-3, and at pressures up to 6.9 MPa by the isochoric method. Fourteen saturated densities were obtained by the observation of meniscus disappearance in the critical region. On the basis of these measurements, the critical parameters of T_c = 376.93 ± 0.01 K and ρ_c = 414 ± 3 kg m^-3 were determined. The present results are compared to an available equation of state.

DOI： 10.1021/acs.jced.8b00452

Language：Japanese   Publishing type：Research paper (other academic)  

Vapor-Liquid Equilibrium Measurements of Binary Refrigerant Mixtures Composed of R1123, R1234yf and R32

DOI： 10.1299/jsmekyushu.2018.71.F11

Language：English   Publishing type：Research paper (scientific journal)  

Saturation pressures for new low global warming potential refrigerants trifluoroethene (R1123, CF₂= CHF) and 3,3,3-trifluoropropene (R1243zf, CF₃CH=CH₂) were measured by the isochoric method for temperatures between 278 and 377 K. Temperature was measured with a 25 standard platinum resistance thermometer on ITS-90. Pressure was measured with a digital quartz pressure transducer. The experimental uncertainties in temperature and pressure are estimated to be 5 mK and 1 kPa (k = 2), respectively. New saturation-pressure correlations for the refrigerants have been formulated based on the present saturation-pressure data. The critical pressures of R1123 and R1243zf were also determined.

DOI： 10.1021/acs.jced.7b00818

Language：English   Publishing type：Research paper (scientific journal)  

PVT properties in the vapor phase of cis-1,3,3,3-tetrafluoropropene (R1234ze(Z)) were measured by a multiple expansion method in the temperature range from 353 to 413 K and at pressures up to 2.7 MPa. Thirty data along four isotherms are obtained in the temperatures between 353 and 413 K. The vapor pressures at the temperatures were also measured by adding a sample of R1234ze(Z) to a sample cell at the vapor-liquid equilibrium conditions. The uncertainties in temperature and pressure measurements are estimated to be within 6 mK and 0.3 kPa, respectively. The expanded uncertainty in density measurement is estimated within no greater than 0.12% (k = 2). The obtained PVT properties and vapor pressures are compared with the existing equation of state.

DOI： 10.1021/acs.jced.7b00263

Language：English  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1080/23744731.2016.1230981

Language：English   Publishing type：Research paper (scientific journal)  

Copyright © 2016 ASHRAE. Measurements of pressure-density-temperature-composition properties, saturated densities, and critical parameters for the low-global warming potential refrigerant blend of the 50 mass&#37; R1234yf (2,3,3,3-tetrafluoroprop-1-ene; CF3CF = CH2) + 50 mass&#37; R1234ze(E) (trans-1,3,3,3-tetrafluoroprop-1-ene; CF3CH = CHF) were measured with two types of isochoric methods. As for the PρTx properties, 38 data along five isochores in one phase region were obtained by the isochoric method. This measurement was made in the range of temperatures from 340 to 430 K, of pressures from 1693 to 6774 kPa, and of densities from 100 to 900 kg·m−3. As for the saturated densities, nine saturated vapor densities and six saturated liquid densities were measured by the direct observation of meniscus disappearance. These experimental data were obtained in the temperature range from 354.62 to 374.28 K and densities between 219 and 870 kg·m−3. On the basis of the present data, the critical temperature Tc = 374.28 K, critical density ρc = 480 kg·m−3, and critical pressure Pc = 3524 kPa for the 50mass&#37; R1234yf + 50mass&#37; R1234ze(E) blend were determined. In addition the critical locus correlations corresponding the composition were proposed for the R1234yf + R1234ze(E) blend.

DOI： 10.1080/23744731.2016.1223975

Language：Japanese  

Language：Japanese  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Measurements of Thermodynamic Properties for the Binary R 245fa + R 134a Mixture:- 2nd Report

DOI： 10.11322/tjsrae.15-46_OA

Language：Japanese   Publishing type：Research paper (scientific journal)  

Measurements of Thermodynamic Properties for the Binary R 245fa + R 134a Mixture:- 1st Report

DOI： 10.11322/tjsrae.15-45_OA

Language：English   Publishing type：Research paper (scientific journal)  

© 2015 Elsevier Ltd and IIR. All rights reserved. Thermodynamic properties are discussed for 1,1,1,2-tetrafluoroethane (R-134a) + 2,3,3,3-tetrafluoropropene (R-1234yf) mixtures. The critical temperatures, densities, and pressures experimentally determined are first presented with their uncertainties. Subsequently a mixture model for calculations of thermodynamic properties is formulated using the multi-fluid approximation. Comparisons to experimental data show that the mixture model calculates the vapor-liquid equilibrium and densities of the mixtures with reasonable accuracies. The critical parameters are also well represented by the mixture model.

DOI： 10.1016/j.ijrefrig.2015.06.011

Language：English   Publishing type：Research paper (scientific journal)  

The 5 pair layered FeSi₂ thermoelectric conversion module was manufactured by sintering five layers of p type and n type powder at the same time, using SPS (spark plasma sintering) method. This process is expected to have higher reliability and shorter manufacturing time compared with conventional process which is performed by joining machined p type and n type element with the electrode. Maximum power of 32.4 mW was provided by this module under the condition of heating temperature 773 K and cooling temperature 293 K. The changes of the module shape and sintering condition greatly changed the performance of this module. By the optimization of the sintering condition and the shape, the performance of this process can be expected to be higher. To obtain the high performance it is necessary to develop the module shape which has large temperature difference with low electric resistance and sintering condition which enable low thermal conductivity with high density.

DOI： 10.2497/jjspm.62.457

Language：Japanese   Publishing type：Research paper (scientific journal)  

The 5 pair layered FeSi2 thermoelectric conversion module was manufactured by sintering five layers of p type and n type powder at the same time, using SPS (spark plasma sintering) method. This process is expected to have higher reliability and shorter manufacturing time compared with conventional process which is performed by joining machined p type and n type element with the electrode. Maximum power of 32.4 mW was provided by this module under the condition of heating temperature 773 K and cooling temperature 293 K. The changes of the module shape and sintering condition greatly changed the performance of this module. By the optimization of the sintering condition and the shape, the performance of this process can be expected to be higher. To obtain the high performance it is necessary to develop the module shape which has large temperature difference with low electric resistance and sintering condition which enable low thermal conductivity with high density.

DOI： 10.2497/jjspm.62.457

Language：Japanese   Publishing type：Research paper (scientific journal)  

© 2015, Journal of the Japan Society of Powder and Powder Metallurgy. All rights reserved. To achieve high performance of thermoelectric conversion module, it is important that the contact electric resistance between thermoelectric element and electrode is decreased. The manufacturing method to perform sintering of FeSi2 powder and joining of the sintered body with Ag metal plates at the same time was examined by using SPS(spark plasma sintering) method. The Ag plates were successfully joined to FeSi2 element by this process. In addition, it was able to lower the resistance of thermoelectric conversion module because the contact electric resistance between the FeSi2 element and the Cu electrode was decreased by joining Ag plates. The thermoelectric conversion modules with various element heights were produced by this process, and the performance of the modules was evaluated under several temperature differences. The most suitable thermoelectric module height, 5 mm, was decided by investigating relations of the module height and the performance. The FeSi2 thermoelectric conversion module consisting of 50 pairs of p-n elements was produced using an element with 5 mm height, and the performance was measured. As a result, the maximum electric power of FeSi2 thermoelectric conversion module of 50 pairs was 1.70 W in the condition of heating temperature at 873 K and/or cooling temperature at 293 K.

DOI： 10.2497/jjspm.62.313

Language：English   Publishing type：Research paper (scientific journal)  

Abstract The surface tension of R1243zf, R1234ze(Z), and R1233zd(E) were measured at temperatures from 270 K to 360 K by an experimental apparatus based on the differential capillary rise method. The deviation between the measured surface tension of R134a and R245fa and the calculated surface tension with REFPROP 9.1 (Lemmon et al., 2013) was ±0.13 mN m^-1, which is less than the estimated propagated uncertainty in surface tension of ±0.2 mN m^-1. Eleven points, thirteen points, and ten points of surface tension data were provided for R1243zf, R1234ze(Z), and R1233zd(E), respectively, in this paper. The measured data and the estimated surface tension using the methods of Miller (1963), Miqueu et al. (2000), and Di Nicola et al. (2011) agree within the standard deviation of ±0.43 mN m^-1. The empirical correlations that represent the measured data within ±0.14 mN m^-1 were proposed for each refrigerant.

DOI： 10.1016/j.ijrefrig.2015.01.005

Language：English   Publishing type：Research paper (scientific journal)  

© 2015 Elsevier Ltd and IIR. All rights reserved. Abstract The surface tension of R1243zf, R1234ze(Z), and R1233zd(E) were measured at temperatures from 270 K to 360 K by an experimental apparatus based on the differential capillary rise method. The deviation between the measured surface tension of R134a and R245fa and the calculated surface tension with REFPROP 9.1 (Lemmon et al., 2013) was ±0.13 mN m-1, which is less than the estimated propagated uncertainty in surface tension of ±0.2 mN m-1. Eleven points, thirteen points, and ten points of surface tension data were provided for R1243zf, R1234ze(Z), and R1233zd(E), respectively, in this paper. The measured data and the estimated surface tension using the methods of Miller (1963), Miqueu et al. (2000), and Di Nicola et al. (2011) agree within the standard deviation of ±0.43 mN m-1. The empirical correlations that represent the measured data within ±0.14 mN m-1 were proposed for each refrigerant.

DOI： 10.1016/j.ijrefrig.2015.01.005

Language：Japanese  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Thermoelectric Properties of layered FeSi₂ Thermoelectric Conversion Module Produced by Spark Plasma Sintering Method

DOI： 10.2497/jjspm.62.457

Language：Japanese   Publishing type：Research paper (scientific journal)  

Thermoelectric Properties of FeSi₂ Thermoelectric Conversion Modules Sintered with Ag Joint Plates by Spark Plasma Sintering Method

DOI： 10.2497/jjspm.62.313

Language：English   Publishing type：Research paper (scientific journal)  

A fundamental equation of state is presented for cis-1,3,3,3- tetrafluoropropene (R-1234ze(Z)). The equation of state is expressed explicitly in the Helmholtz energy with independent variables of temperature and density. The equation of state is based on experimental data for the critical parameters, vapor pressures, densities of the liquid and vapor phases, and sound speeds in the vapor phase. All thermodynamic properties can be derived as derivatives of the Helmholtz energy. The equation is valid for temperatures from 273 K to 430 K and for pressures up to 6 MPa. The estimated uncertainties of properties calculated from the equation are 0.15&#37; in vapor pressures, 0.4&#37; in vapor densities, 0.2&#37; in liquid densities, and 0.05&#37; in the vapor phase sound speeds. The equation exhibits reasonable extrapolation behavior in regions away from the experimental data. © 2014 Elsevier Ltd and IIR. All rights reserved.

DOI： 10.1016/j.ijrefrig.2013.12.018

Language：Japanese  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

The vapor-liquid coexistence curves near the critical point of the binary mixture of 2,3,3,3-tetrafluoropropene (R-1234yf) + difluoromethane (R-32) were measured by means of the visual observation of meniscus disappearance. Eleven, eighteen, and eleven saturated densities were obtained for mixtures with 50.00 mass&#37;, 80.01 mass&#37;, and 90.00 mass&#37; of R-1234yf, respectively. The critical temperatures, critical densities, and critical molar volumes of the mixtures were determined from the meniscus disappearing level and the intensity of the critical opalescence. The critical pressures of the mixtures were also determined from the analysis of pρTx measurements. The composition dependence of the critical parameters was formulated with simple correlations. © 2013 Elsevier Ltd and IIR. All rights reserved.

DOI： 10.1016/j.ijrefrig.2013.02.005

Language：English   Publishing type：Research paper (scientific journal)  

The surface tensions of trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(E)) alone and when mixed with difluoromethane (HFC-32) were measured using the differential capillary-rise method. Twenty-three data points for HFO-1234ze(E) were obtained in the temperature range 273-333 K. Twenty-six data points for the 50.00 mass% HFO-1234ze(E)+50.00 mass% HFC-32 mixture were obtained in the temperature range from 273-323 K. The experimental uncertainty of the surface tension was estimated to be 0.2 mN m^-1 for pure HFO-1234ze(E) and 0.3 mN m^-1 for the fluid mixture. Based on the obtained data, the surface tension correlations for HFO-1234ze(E) and the HFO-1234ze(E)+HFC-32 mixture were formulated. The correlations can represent the data with a standard deviation of 0.06 mN m-¹ for HFO-1234ze(E) and 0.18 mN m^_1 for the HFO-1234ze(E)+HFC-32 mixture.

DOI： 10.1252/jcej.13we021

Language：Japanese  

3成分系R‐1234ze(E)+R‐32+CO₂混合冷媒の熱力学性質の測定

Language：Japanese  

Language：Japanese  

Language：Japanese  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Measurements of Density and Isobaric Specific Heat Capacity for HFO-1234ze(E)+HFC-32 Mixtures

Language：Japanese  

<tt>An experimental apparatus for measuring </tt><tt>PρTx </tt><tt>(pressure-density-temperature-composition) properties along isochores was constructed. After the calibration of pressure sensor and the determination of the inner volume of sample vessel, the reproducibility of the experimental apparatus was confirmed by the measurement of isochores for pure HFC-134a (1,1,1,2-tetrafluoroethane). The </tt><tt>PρTx </tt><tt>properties of the 50 mass&#37; HFO-1234ze(E) (trans-1,3,3,3-tetrafluoropropene) + 50 mass&#37; HFC-32 (difluoromethane) mixtures and those of the 75 mass&#37; HFO-1234ze(E) + 25 mass&#37; HFC-32 mixtures were measured for five isochores including 128 </tt><tt>PρTx </tt><tt>property data points and for seven isochores including 188 </tt><tt>PρTx </tt><tt>property data points, respectively. The critical pressures were determined from the present isochores close to the critical density against the critical temperature. The relationship between pressure and temperature at vapor-liquid equilibrium was graphically determined from thepresentisochores</tt><tt>. </tt>

DOI： 10.11322/tjsrae.28.415

Language：Japanese  

Language：Japanese  

Language：Japanese   Publishing type：Research paper (scientific journal)  

A Review of Study on Thermodynamic Properties of Hydrofluoroolefin Refrigerants R 1234yf and R 1234ze(E)

Language：Japanese  

Language：Japanese  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Measurements of Density and Isobaric Specific Heat Capacity for HFO-1234ze(E)+HFC-32 Mixtures

DOI： 10.11322/tjsrae.28.427

Language：Japanese   Publishing type：Research paper (scientific journal)  

A Review of Study on Thermodynamic Properties of Hydrofluoroolefin Refrigerants R 1234yf and R 1234ze(E)

DOI： 10.11322/tjsrae.28.1

Language：English   Publishing type：Research paper (scientific journal)  

Measurements of the PpT properties for trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(E)) in the gaseous phase were carried out using metal bellows volumometer. A total of 204 PpT property values was obtained in the range of temperatures from (310 to 360) K, pressures from (657 to 2300) kPa, and densities from (34 to 146) kg•m-3. The sample purity was better than 99.96 &#37; in mole fraction. The present data were compared with the existing data and equations of state. The Benedict-Webb-Rubin-Starling (BWRS) and Martin-Hou equations of state were used to correlate the present data. © 2010 American Chemical Society.

DOI： 10.1021/je100707s

Language：English   Publishing type：Research paper (scientific journal)  

The isobaric specific heat capacity and density for dimethyl ether were measured in the temperature range from (310 to 360) K at pressures up to 5 MPa in the liquid state. Measurements were conducted by the metal-bellows calorimeter. The uncertainties of isobaric specific heat capacity and density measurements were estimated to be less than 5 &#37; and 0.2 &#37;, respectively. Experimental values for the isobaric specific heat capacity and density were correlated as functions of pressure and temperature. In addition, the saturated liquid isobaric specific heat capacity and saturated liquid density were obtained from extrapolation of these correlations to the vapor pressure. © 2010 American Chemical Society.

DOI： 10.1021/je900922x

Language：English   Publishing type：Research paper (scientific journal)  

The isobaric specific heat capacity of trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(E)) in the liquid phase was measured using a metal-bellows calorimeter. Twenty-six data points were obtained in the temperature range from (310 to 370) K and pressure range from (2 to 5) MPa. The relative experimental uncertainty of the isobaric specific heat capacity was estimated to be 5 &#37;. On the basis of the present data, the correlation of the isobaric specific heat capacity in the liquid phase was formulated as functions of temperature and pressure. The heat capacities of saturated liquid were derived from this correlation by substituting the vapor pressure. © 2010 American Chemical Society.

DOI： 10.1021/je900799e

Language：English   Publishing type：Research paper (scientific journal)  

Measurements of the vapor pressures and p ρ T properties for trans -1,3,3,3-tetrafluoropropene (HFO-1234ze(E))
The vapor pressures and pρT properties for trans-1,3,3,3- tetrafluoropropene (HFO-1234ze(E)) are measured using a metal-bellows cell. As for the vapor pressure, eight data points are obtained in the temperature range from (310 to 380) K and pressure range from (703 to 3458) kPa. The data of the vapor pressure is correlated by the Wagner type equation with the absolute average deviation of 0.02 &#37;. By extrapolating the vapor-pressure correlation to the critical temperature, the critical pressure is determined to be 3632 kPa. The acentric factor is also determined to be 0.296 by using the vapor-pressure correlation. As for the pρT properties, 26 data points are obtained in the temperature range from (310 to 370) K and pressure range from (2000 to 5000) kPa. The data of the pρT properties are correlated by the Sato equation with the absolute average deviation of 0.04 &#37;. Seven data points of the saturated liquid density are obtained by extrapolating the correlation of the pρT properties to the vapor pressure. © 2010 American Chemical Society.

DOI： 10.1021/je900756g

Language：English   Publishing type：Research paper (scientific journal)  

Measurements of the thermodynamic properties of HFO-1234yf were conducted. The critical temperature T_C, critical density ρ_C, and critical pressure P_C, were measured by the visual observation of the meniscus disappearance, and were determined to be 367.85 ± 0.01 K, 478 ± 3 kg/m³, and 3382 ± 3 kPa, respectively. Vapor pressures were measured by a batch-type calorimeter with a metal-bellows in the temperature range from 310 K to 360 K and correlated by the Wagner-type equation. Surface tensions were measured by the differential capillary-rise method in the temperature range from 273 K to 340 K and correlated by the van der-Waals type equation. The acentric factor was determined to be 0.280 with the vapor pressure correlation. Based on the critical parameters and acentric factor, saturated vapor and liquid densities were estimated by the Peng-Robinson equation and the Hankinson-Thomson equation, respectively. The heat of vaporization was also calculated from the Clausius-Clapeyron equation.

DOI： 10.1016/j.ijrefrig.2009.10.003

Language：English   Publishing type：Research paper (scientific journal)  

Measurements of the saturated vapor and liquid densities near the critical point for trans-1,3,3,3-tetrafluoropropene (CFH=CHCF3; HFO-1234ze(E)) were carried out in the reduced temperature range of 0.962 < T/Tc < 1 and in the reduced density range of 0.40 < ρ/ρc < 1.70. Taking into consideration the meniscus disappearing level as well as the intensity of the critical opalescence, the critical temperature T c and critical density ρc were determined experimentally. The critical pressure Pc was calculated by extrapolating the vapor-pressure equation to the critical temperature. The critical parameters reported in this paper are Tc = (382.51 ± 0.01) K, ρc = (486 ± 3) kgm-3, Vc = (235 ± 2) cm3mol-1, and Pc = (3632 ± 3) kPa. The saturated liquid density correlation is formulated using the present data. In addition, the critical exponent β along the coexistence curve was also discussed. © 2009 American Chemical Society.

DOI： 10.1021/je900696z

Language：English   Publishing type：Research paper (scientific journal)  

Measurements of the isobaric specific heat capacity for the hydrocarbons 1,1,1-trifluoroethane (R143a), pentafluoroethane (R125), and difluoromethane (R32) were carried out in the liquid phase at a pressure of 5 MPa by using a batch type calorimeter equipped with a metal bellows. Ten data points of the isobaric specific heat capacity for R143a, 11 data points for R125, and seven data points for R32 were obtained in the temperature range from (310 to 350) K and at a pressure of 5 MPa. The experimental uncertainties are estimated to be 5 mK for temperature, 3 kPa for pressure, and 5.2 &#37; for isobaric specific heat capacity. The present results were compared with the literature data and the values calculated from the equation of state. The correlations of the isobaric specific heat capacity were formulated as a function of temperature at a pressure of 5 MPa. Maximum deviations of the present results from correlations were 1.4 &#37; for R143a, 1.5 &#37; for R125, and 0.9 &#37; for R32, respectively. © 2009 American Chemical Society.

DOI： 10.1021/je900661c

Language：English   Publishing type：Research paper (scientific journal)  

The isobaric specific heat capacity and density of the HFO-1234yf (2,3,3,3-tetrafluoropropene, CH₂=CFCF₃) in the liquid state have been measured in the temperature range from (310 to 360) K at pressures up to 5 MPa. The uncertainties in temperature, pressure, isobaric specific heat capacity, and density measurements were estimated to be less than 5 mK, 3 kPa, 5 %, and 0.2 %, respectively. A sample with purity of 99.99 mol % or greater was used for the measurement. Experimental values for the isobaric specific heat capacity were correlated as a function of pressure along isotherms, and those for density were correlated as functions of pressure and temperature. In addition, the saturated liquid isobaric specific heat capacity and density were obtained from extrapolation of these correlations to the vapor pressure.

DOI： 10.1021/je900515a

Language：English   Publishing type：Research paper (scientific journal)  

This paper presents a timely and reliable equation of state for 2,3,3,3-tetrafluoropropene (HFO-1234yf) whose thermodynamic property information is strongly desired. The Patel-Teja (PT) equation of state and the extended corresponding state (ECS) model have been individually applied to property modeling for this new refrigerant. Comparisons of predicted values with the equation/model were made with the most recent experimental data. Both the PT equation of state and the ECS model can represent the vapor pressures with an accuracy of 0.2%. However, the ECS model is much better than the PT equation of state in the predictions for the liquid density and isobaric heat capacity. The uncertainties of calculated values with the ECS model are 0.5% in liquid density and 2.5% in isobaric heat capacity. The use of the ECS model is recommended for a detailed assessment of HFO-1234yf. Thermodynamic property tables and diagrams generated using the ECS model are provided.

DOI： 10.1016/j.ijrefrig.2009.09.004

Language：English   Publishing type：Research paper (scientific journal)  

This paper presents a timely and reliable equation of state for 2,3,3,3-tetrafluoropropene (HFO-1234yf) whose thermodynamic property information is strongly desired. The Patel-Teja (PT) equation of state and the extended corresponding state (ECS) model have been individually applied to property modeling for this new refrigerant. Comparisons of predicted values with the equation/model were made with the most recent experimental data. Both the PT equation of state and the ECS model can represent the vapor pressures with an accuracy of 0.2%. However, the ECS model is much better than the PT equation of state in the predictions for the liquid density and isobaric heat capacity. The uncertainties of calculated values with the ECS model are 0.5% in liquid density and 2.5% in isobaric heat capacity. The use of the ECS model is recommended for a detailed assessment of HFO-1234yf. Thermodynamic property tables and diagrams generated using the ECS model are provided. © 2009 Elsevier Ltd and IIR.

DOI： 10.1016/j.ijrefrig.2009.09.004

Language：English   Publishing type：Research paper (scientific journal)  

A temperature-change sensor by thermoelectric elements that is directly connected to a p-type element and an n-type element was developed. A β-FeSi2 thermo-electric semiconductor made by a spark plasma sintering method was used as a prototype sensor. Evaluation of this thermoelectric temperature-change sensor was carried out by measuring its electromotive force when it was dropped into a thermo-stated water bath. It was confirmed that there existed a correlation between the temperature difference and the electromotive force of the sensor, i.e., approximately 5 mV of electromotive force was generated at a temperature difference of 30 K. In addition, the dependence of electromotive force on the size and properties of the thermoelectric elements was evaluated by carrying out FEM analysis. © 2009 Wiley Periodicals, Inc.

DOI： 10.1002/htj.20268

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

There were no data of the surface tension for the R290 + R32 mixture which is expected as one of the new refrigerant mixtures, and its prediction is considered to be difficult because it is a mixture of a very polar molecule with a nonpolar molecule. In this work, the surface tension measurements for the R290 + R32 mixture were carried out by the differential capillary-rise method modified for measuring mixtures. Thirtyone, thirty-five, and thirty-three data points were obtained with changing the composition of the mixture at T = 280 K, 290 K, and 300 K, respectively. The experimental uncertainties of temperature and surface tension are estimated to be within 20 mK and 0.2 mN·m -1, respectively. The excess molar surface tension is also calculated by the present data, and its uncertainty was estimated to be 0.3 mN·m-1. The excess molar surface tension was correlated as a function of composition. The deviation of the present data from the present correlation was within the experimental uncertainty. © 2009 American Chemical Society.

DOI： 10.1021/je800756r

Language：English   Publishing type：Research paper (scientific journal)  

Vapor - liquid equilibrium (VLE) of the CO2 + R290 mixture has been measured by the recirculation method. Thirty-three data sets of VLE measurements were obtained in the temperature range between (260 and 290) K and in the pressure range between (408 and 4710) kPa. The experimental uncertainties of the temperature, pressure, and composition measurements are estimated to be within 3 mK, 3 kPa, and 0.11 &#37;, respectively. The present data were compared with the calculation by the REFPROP and correlated well by two cubic equations of state, i.e., the Peng - Robinson equation and the Soave - Redlich - Kwong equation. © 2009 American Chemical Society.

DOI： 10.1021/je800938s

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese  

As for the plan of Agency for Natural Resources and Energy, Ministry of Economy, Trade and Industry, the Information Center for Energy and Environment Education is tackling to the program for the regional base university of energy education from 2002. It is the main objectives to teach the concept of energy conservation and renewable energy for the children learning at elementary schools, junior high schools, and high schools. In this stage, 36 universities are active as the regional base university in Japan. Moreover 11 universities are selected as the advanced regional base university. From 2004 to 2006, Iwaki Meisei University was active as the regional base university to construct the model of energy education program based on the regional cooperation. At the present, we are active as the advanced regional base university to make the wide network connecting the university, schools, industries, city, prefecture, and government. The activities in Iwaki Meisei University are consisted of four approaches, i.e., (1) experience study, (2) opening of symposium, (3) external class for students and parents, and (4) development of educational equipments.

Language：English  

Language：Japanese  

Language：English   Publishing type：Research paper (scientific journal)  

The surface tensions of R290, R600a and R290/R600a mixture have been measured by the modified differential capillary-rise method. Twenty-two data points for R290 and 21 data points for R600a were obtained in the temperature range between 273 K and 354 K, and 43 data points for R290/R600a mixture on three isotherms of 278 K, 300 K and 320 K were obtained. The experimental uncertainties of temperature and surface tension are estimated to be within 20 mK and 0.2 mN m-1, respectively. Surface tension correlations as a function of temperature for pure R290 and R600a were formulated in the temperature range between 253 K and critical temperature, and the correlation as a function of the composition for R290/R600a mixture was discussed at 278 K, 300 K and 320 K. It is found that the surface tension for R290/R600a mixture can be reproduced by the simple mixing rule by mole fraction with the correlations of both pure components. © 2007 Elsevier Ltd and IIR.

DOI： 10.1016/j.ijrefrig.2007.04.002

Language：English   Publishing type：Research paper (scientific journal)  

Hydrocarbons such as propane (R-290), n-butane (R-600), and isobutane (R-600a) are expected candidates for CFC, HCFC, and HFC alternative working fluids for refrigerators and heat pump systems. Hydrocarbons (HCs) are environmentally acceptable refrigerants; however, most HCs have the problem of flammability. In order to maintain the safety of home refrigerators and air-conditioners, mixing a small amount of HFCs with HCs may be effective. In our previous study, the vapor-liquid equilibrium (VLE) measurements for the binary mixtures of R-290 + R-600a and the difluoromethane (R-32) + R-290 have already been performed. This study measured the VLEs of the binary mixture of R-32 + R-600a and the ternary mixture of R-290 + R-600a + R-32. Based on the experimental data, the VLEs for three binary mixtures were correlated by using the cubic equations of state with the conventional mixing rule, and the appropriate binary interaction parameters were determined for each binary mixture. For the R-290 + R-600a and R-32 + R-290 mixtures, the correlations were successful. For the R-32 + R-600a mixture, however, because of a relatively high nonideality, the accuracy of correlation was less than that for the other two mixtures. By applying the mixing rule based on the excess Gibbs free energy model, the accuracy was well improved. Moreover, by using the binary interaction parameters for each binary mixture the prediction of the VLE for the R-290 + R-600a + R-32 mixture was tested, and predicted bubble-point pressures were compared with the experimental values. The accuracy of this prediction was at similar level to the VLE correlation for the R-32 + R-600a mixture. © 2007 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.fluid.2007.06.029

Language：Japanese  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

The surface tensions of 1,1,1,2,2,3,3,4,4-nonafluorohexane (CF ₃CF₂CF₂CF₂CH₂CH ₃) and 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoro-ethyl ether (CHF ₂CF₂OCH₂CF₃), which are potential alternatives to HCFC solvents, were measured by the differential capillary-rise method. 20 data points for 1,1,1,2,2,3,3,4,4-nonafluorohexane and 17 data points for 1,1,2,2-tetrafluoroethyl-2,2,2,-trifluoroethyl ether were obtained in the temperature range of 289-348 K. The experimental uncertainties of temperature and surface tension measurements were estimated to be within 20 mK and 0.14 mN·m^-1, respectively. Surface tension correlations for 1,1,1,2,2,3,3,4,4-nonafluorohexane and 1,1,2,2-tetrafluoroethyl-2,2,2- trifluoroethyl ether were formulated and were found to reproduce the present data within the limits of experimental uncertainty.

DOI： 10.1252/kakoronbunshu.33.1

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)  

Measurements of the vapor-liquid coexistence curve near the critical point for 2-methylpropane (isobutane; R600a) were carried out in the reduced temperature range of 0.957 < T/Tc < 1 and in the reduced density range of 0.40 < ρ/ρc < 1.70, and the critical temperature Tc and critical density ρc were determined. The critical pressure Pc was calculated by extrapolating reliable vapor-pressure data in the vicinity of the critical point. The critical parameters determined are Tc = (407.795 ± 0.010) K, ρc = (229 ± 2) kg·m-3, Vc = (253.8 ± 2.2) cm3·mol-1, and Pc = (3628.2 ± 1.4) kPa. In addition, the critical exponent β along the coexistence curve is discussed. © 2006 American Chemical Society.

DOI： 10.1021/je050328d

Language：English   Publishing type：Research paper (scientific journal)  

In this paper, the simple and useful procedures of the surface tension measurement are reported. The principles and calculation methods as well as the experimental technique are also represented with respect to the typical methods, i.e., Wilhelmy method, ring method, capillary rise method, and so on. Especially, the differential capillary rise method, which is adopted by the author for the surface tension measurements under high pressures are explained in detail.

Language：English  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English  

PTxy data (bubble-point and dew-point pressures at a specific composition) for two binary systems, propane (1) + n-butane (2) and propane (1) + isobutane (3), are presented in this paper. These binary systems are under consideration for use as a refrigerant for a Lorentz cycle. A recirculation method along with the aid of a new composition measurement system was employed. The experimental uncertainty is 3 mK for temperature, 0.027&#37; + 1.04 kPa for pressure, and 0.11 mol &#37; for composition. A total of 60 data points were obtained in the temperature range of (270 to 310) K for propane (1) + n-butane (2) and (260 to 320) K for propane (1) + isobutane (3). Comparisons of the present data with available mixture thermodynamic models and other experimental data are discussed in this paper. © 2005 American Chemical Society.

DOI： 10.1021/je0496701

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Language：English   Publishing type：Research paper (other academic)  

Vapor-liquid coexistence curves in the critical region for binary difluoromethane (R32) + propane (R290) mixtures have been measured by visual observation of the meniscus disappearance. Twelve and 15 data of saturated vapor and liquid densities for 70mass&#37; R32 and 90mass&#37; R32, respectively, have been obtained in the temperature range of 316K<T<345K and in the density range of 109kg/m3<ρ<717kg/m3. The uncertainties of the temperature, density, and composition measurements are estimated to be within 10mK, 0.3-1.1kg/m3, and 0.03&#37;, respectively. On the basis of the present results of the vapor-liquid coexistence curve, the critical temperature and the critical density for the R32 + R290 system have been determined considering the meniscus disappearance level as well as the intensity of the critical opalescence. The critical pressure of the mixtures were estimated based on the measured critical temperature and the REFPROP database. © 2004 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.fluid.2004.02.004

Language：Japanese   Publishing type：Research paper (scientific journal)  

Vapor-Liquid Equilibrium Measurements of the Binary R32+R125 Refrigerant Mixture

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

A new apparatus for precise measurements of the vapor-liquid equilibria of mixtures by the circulation method has been developed. This apparatus has two special components: a high-stability temperature control system and a helium pressurization system. The temperature in the liquid bath surrounding the sample cell is kept constant within ±0.5 mK. The helium pressurization system increases the pressure of the sampled mixture when measuring the compositions at low temperatures by gas chromatography. With these components, the uncertainty in measuring the vapor-liquid equilibria has been reduced. Using this apparatus, the vapor-liquid equilibria of HFC-32/134a mixtures were measured in a temperature range of 263.15 to 293.15 K. These results are in good agreement with the calculated results from REFPROP (Ver. 6.0.1) with a relative pressure difference of about 2&#37;.

DOI： 10.1023/A:1015407205188

Language：Japanese   Publishing type：Research paper (scientific journal)  

Current Information on the Properties of Hydrofluorocarbons(HFCs) and Other Pure Refrigerants

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Language：English   Publishing type：Research paper (scientific journal)  

The vapor-liquid equilibrium for pentafluoroethane (R125) + 1,1,1,2-tetrafluoroethane (R134a) was measured along four isotherms between 283 K and 313 K. The vapor-liquid coexistence curve at constant composition near the mixture critical point was measured by the observation of the meniscus disappearance. The critical temperatures and critical densities of the 0.2670 and 0.6648 mole fraction of R125 were determined from the saturation densities along the coexistence curve in the critical region. In addition, the critical locus for the R125/R134a mixture is correlated as a function of composition.

DOI： 10.1021/je980265h

Language：English  

Language：English   Publishing type：Research paper (scientific journal)  

The vapor-liquid equilibrium for pentafluoroethane (R125) + 1,1,1-trifluoroethane (R143a) was measured by the static method in the temperature range between 273.15 K and 313.15 K. The vapor-liquid coexistence curve near the critical point was measured by observation of the meniscus disappearance. The critical temperatures and critical densities of the 0.4118 and 0.6208 mole fraction of R125 were determined from the saturation densities along the coexistence curve in the critical region. In addition, the critical locus for the R125/R143a mixture is correlated as a function of composition.

DOI： 10.1021/je980266+

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

The surface tension of several refrigerant mixtures was measured and correlated. The measurements were conducted using the differential capillary rise method (DCRM) under conditions of coexistence of the sample liquid and its saturated vapor in equilibrium. The temperature range covered was from 273 to 323 K. The resulting data were represented by a mixing rule using mass friction based on the van der Waals correlation.

DOI： 10.1023/A:1021482231102

Language：English   Publishing type：Research paper (scientific journal)  

The vapor-liquid equilibrium of the mixture composed of difluoromethane (R-32) and propane (R-290) was studied in the temperature range between 273.15 and 313.15 K. The experimental uncertainties of temperature, pressure, and composition measurements were estimated to be within ± 10 mK, ± 3 kPa, and ± 0.4 mol%, respectively. Comparisons between the present data and available experimental data were made using the Helmholtz free energy mixture model (HMM) adopted in the thermophysical properties program package, REFPROP 6.0, as a baseline. In addition, the existence of an azeotrope and the determination of new adjustable parameters for HMM for the R-32 + R-290 mixture are discussed.

DOI： 10.1023/A:1022653020420

Language：English   Publishing type：Research paper (scientific journal)  

The plane of vapor-liquid criticality for ternary refrigerant mixtures of difluoromethane (R-32)+pentafluoroethane (R-125)+1,1,1,2-tetrafluoroethane (R-134a) was determined from data on the vapor-liquid coexistence curve near the mixture critical points. The compositions (mass percentage) of the mixtures studied were 23% R-32+25% R-125+52% R-134a (R-407C), 25% R-32+15% R-125+60% R-134a (R-407E), and 20% R-32+40% R-125+40% R-134a (R-407A). The critical temperature of each mixture was determined by observation of the disappearance of the meniscus. The critical density of each mixture was determined on the basis of meniscus disappearance level and the intensity of the critical opalescence. The uncertainties of the temperature, density, and composition measurements are estimated as ±10 mK, ±5 kg·m^-3, and ±0.05%, respectively. In addition, predictive methods for the critical parameters of R-32/125/134a mixtures are discussed.

DOI： 10.1023/A:1021445222925

Language：English  

The vapor-liquid equilibrium of the mixture composed of difluoromethane (R-32) and propane (R-290) was studied in the temperature range between 273.15 and 313.15 K. The experimental uncertainties of temperature, pressure, and composition measurements were estimated to be within ± 10 mK, ± 3 kPa, and ± 0.4 mol&#37;, respectively. Comparisons between the present data and available experimental data were made using the Helmholtz free energy mixture model (HMM) adopted in the thermophysical properties program package, REFPROP 6.0, as a baseline. In addition, the existence of an azeotrope and the determination of new adjustable parameters for HMM for the R-32 + R-290 mixture are discussed.

DOI： 10.1023/A:1022653020420

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Apparatus of the vapor-pressure measurements for natural refrigerants

DOI： 10.11322/tjsrae.15.335

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

The surface tensions for 1,1,1-trifluoroethane (R-143a), 1,1,1,2-tetrafluoroethane (R-134a), 1,1-dichloro-2,2,3,3,3-pentafluoropropane (R-225ca), and 1,3-dichloro-1,2,2,3,3-pentafluoropropane (R-225cb) have been measured by the differential capillary rise method. The results were obtained in the temperature range between 273 K and 343 K. The experimental uncertainties of temperature and surface tension are estimated to be within ±20 mK and ±0.15 mN·m^-1, respectively. A correlation for the surface tension as a function of temperature is presented.

DOI： 10.1021/je960274v

Language：English   Publishing type：Research paper (scientific journal)  

The vapor-liquid equilibrium for difluomethane + pentafluoroethane (R-32 + R-125) was measured by the static method in the temperature range between 283 K and 313 K. The vapor-liquid coexistence curve near the critical point was measured by the observation of the meniscus disappearance. The critical temperatures and critical densities of a 30 mass % R-32 and a 60 mass % R-32 mixture were determined on the basis of the saturation densities along the coexistence curve in the critical region. In addition, the critical locus for the R-32 + R-125 mixture is correlated as the function of composition.

DOI： 10.1021/je9701083

Language：Japanese  

Language：English   Publishing type：Research paper (scientific journal)  

Measurements of the vapor-liquid coexistence curve near the critical point were carried out for 1,1,1-trifluoroethane (R-143a) in the reduced temperature range of 0.97 < T/Tc < 1 and in the reduced density range of 0.45 < ρ/ρc < 1.53. Taking into consideration of the disappearing level of the meniscus as well as the intensity of the critical opalescence, the critical temperature Tc and critical density ρc were determined. With respect to the critical pressure Pc, we calculated the value from the new vapor-pressure equation made by ourselves in order to represent the behavior of vapor-pressures near the critical point. The critical parameters determined in this paper are Tc = 345.88 + δT K, δT = 0.00±0.01 K, ρc = 431 ± 3 kg m-3, and Pc = 3764 + 78.73δT ± 5 kPa. In addition, the critical exponent β along the coexistence curve was also discussed.

DOI： 10.1016/s0378-3812(96)03089-0

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Two kinds of equilibrium measurements of binary R-32/134a mixtures were carried out. The vapor-liquid equilibria were measured by the static method in the temperature range between 283 and 313 K. On the basis of the present experimental data, the temperature dependence of the binary interaction parameter k12 for two equations of state, namely, the Soave-Redlich-Kwong equation and Carnahan-Starling-De Santis equation, was discussed. The vapor-liquid coexistence curve near the critical point was also measured by the observation of meniscus disappearance. The critical temperatures and critical densities of 30 and 70 wt&#37; R-32 mixtures were determined on the basis of the saturation densities along the coexistence curve in the critical region. In addition, a correlation of the critical locus for this mixture is proposed as a function of composition. © 1995 Plenum Publishing Corporation.

DOI： 10.1007/BF02081285

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

The surface tension of six alternative refrigerants, i.e., HFC-32 (CH, F, ). HCFC-124 (CHClFCF,), HFC-125 (CHF2CF3). HCFC-14lb ICH,CCI,F). HCFC-142b (CH3CCIF2), and HFC-152a (CH3CHF2), has been measured in the present study. The measurements were conducted under equilibrium conditions between the liquid and its saturated vapor. The differential capillary-rise method (DORM) used two glass capillaries, with inner radii of 0.3034 ± 0.0002 and 0.5717 ±0.0002 mm, respectively. Temperatures in the range from 270 to 340 K were considered. The accuracy of surface tension measurements is estimated to be within ±0.2 mN · m-1. The temperatures are accurate to within ±20 mK. The temperature dependence of the resultant data were successfully represented by van der Waals' correlations to within ±(1.1 mN m-1 for each substance. Available surface tension data are compared with the present data. © 1995 Plenum Publishing Corporation.

DOI： 10.1007/BF01438864

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Surface tension measurements of fluids under high pressure is described here. A topic focused on is the fluorocarbon refrigerants and alternative refrigerants, since the authors have much experience for these fluids. The principle and the experimental apparatus of capillary rise method is briefly explained, since this method is widely utilized to measure the surface tension under high pressure. This article introduces the summary of the experimental results and correlations for surface tension of HCFCs and HFCs which are the candidate fluids for alternative refrigerants.

DOI： 10.4131/jshpreview.3.324

Language：English   Publishing type：Research paper (scientific journal)  

The vapour-liquid coexistence curves near the critical point for HFC134a (CF₃CH₂F: 1,1,1,2-tetrafluoroethane), HFC32 (CH₂F₂: difluoromethane) and HFC125 (CHF₂CF₃: pentafluoroethane) have been measured by visual observation of the meniscus disappearance. Three sets of 17 experimental results for the saturated liquid or vapour densities for HFC134a, HFC32 and HFC125 have been obtained in the reduced temperature range T/T_c > 0.96 and in the reduced density range 0.4 < ρ/ρ_c < 1.7. From these measurements, the critical temperature and the critical density for these HFCs have been determined in consideration of the meniscus disappearance level as well as the intensity of the critical opalescence. The critical pressure has been calculated by the extrapolation of the vapour-pressure correlation. The uncertainties of the critical temperature, critical density and critical pressure are estimated to be within ± 10 mK, ± 5 kg m^-3 and ± 9 kPa, respectively.

DOI： 10.1016/0140-7007(94)90028-0

Language：Japanese  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Others   Publishing type：Research paper (scientific journal)  

Measurements of the surface tension for two kinds of CFC alternatives, i.e., HCFC-123 (2,2-dichloro-1,1,1-trifluoroethane), and HFC-134a (1,1,1,2-tetrafluoroethane), have been made by the differential capillary rise method (DCRM) and the vertical plate method (VPM). For HCFC-123, 15 data have been obtained by DCRM in the temperature range between 273 and 333 K within the uncertainty of ±0.1mN/m, and 21 data have been obtained by VPM in the temperature range between 273 and 290 K within the uncertainty of ±0.2mN/m. For HFC-134a, 17 data have been obtained by DCRM in the temperature range between 276 and 329 K within the uncertainty of ±0.1mN/m. The uncertainty of temperature measurement by DCRM is estimated within ±20mK, whereas that by VPM within ±30mK. New correlations of the surface tension for HCFC-123 and HFC-134a have been also proposed.

DOI： 10.11322/tjsrae.9.191

Language：English   Publishing type：Research paper (scientific journal)  

A new apparatus for measurements of PVT properties and their derivatives with a metal bellows was designed for fluids and fluid mixtures of a fixed composition for pressures up to 20 MPa in the range of temperatures from room-temperature condition to 473 K. The apparatus, procedures, and results of calibrations are described. The capabilities of the apparatus are illustrated by means of the vapor-pressure measurements for chlorodifluoromethane and the PVT measurements of sulfur hexafluoride. Temperatures were set and kept constant at the values desired within ±3 mK and pressures within ±2 kPa. It was shown that density derivatives with respect to pressure at constant temperature and those with respect to temperature at constant pressure may both obtain from the experimental results.

DOI： 10.1063/1.1141059

Language：English   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Measurements of the vapor-liquid coexistence curve in the critical region for the refrigerant mixture of bromotrHIuoromethane (CBrF3, R 13B1) and 1,2-dlchloro-1,1,2,2-tetrafluoroethane (CCIF2CCIF2, R 114) were made by visual observation of the disappearance of the meniscus at the vapor-liquid Interface within an optical cell. Eighteen saturated-vapor densities and 21 saturated-liquid densities for four different compositions of 25, 50, 70, and 80 wt &#37; R 13B1 between 345 and 406 K were obtained in the range of densities 356-1166 kg/m3. The experimental error of temperature, density, and mass fraction was estimated within ±15 mK, ±0.5&#37;, and ±0.05&#37;, respectively. On the basis of these measurements, the critical curve of the R 13B1 + R 114 system is determined and compared with several predictive methods. In addition, new correlation so as to represent the composition dependence of the critical parameters for the R 13B1 + R 114 system is proposed. © 1988, American Chemical Society. All rights reserved.

DOI： 10.1021/je00051a009

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1299/jsmeb1988.31.3_573

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Journal of Chemical and Engineering Data

Language：Japanese  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Others  

MEASUREMENT OF VAPOR PRESSURE, VAPOR-LIQUID COEXISTENCE CURVE AND CRITICAL PARAMETERS OF REFRIGERANT 152a.
Forty-four vapor pressures of Refrigerant 152a (CH//3CHF//2: 1,1-difluoroethane) between 273 K and 386 K have been measured in the range of pressures from 0. 26 MPa to 4. 48 MPa. Ten saturated liquid densities and eleven saturated vapor densities near the critical point have also been measured in the range of temperatures from 370 K to the critical temperature which corresponds to a density variation of 153 kg multiplied by (times) m** minus **3 to 635 kg multiplied by (times) m** minus **3. The experimental uncertainties of temperature, pressure and density measurements have been estimated within 10 mK, 0. 8 kPa and 0. 55&#37;, respectively. On the basis of these results, the critical temperature, critical pressure and critical density of R 152a have been determined to be 386. 44 K, 4. 519 8 MPa and 368 kg multiplied by (times) m** minus 3, respectively, in consideration of the meniscus disappearing level as well as the intensity of the critical opalescence.

DOI： 10.1299/jsme1987.30.1106

Language：English   Publishing type：Research paper (scientific journal)  

Forty-four vapor pressures of Refrigerant 152 a (CH₃ CHF₂ : 1, 1-difluoroethane) between 273 and 386 K were measured in the range of pressures from 0.26 to 4.48 MPa. Ten saturated liquid densities and eleven saturated vapor densities near the critical point were also measured in the range of temperatures from 370 K to the critical temperature which corresponds to a density variation of 153 to 635 kg·m^-3. The experimental uncertainties of temperature, pressure and density measurements were estimated within ±10 mK, ±0.8 kPa and ±0. 55 %, respectively. On the basis of these results, the critical temperature, critical pressure and critical density of R 152 a were determined to be 386.44 K, 4.5198 MPa and 368 kg·m^-3, respectively, in consideration of the meniscus disappearing level as well as the intensity of the critical opalescence. In addition, the correlation of vapor pressure and that of the vapor-liquid coexistence curve were also proposed.

DOI： 10.1299/kikaib.53.1379

Language：English   Publishing type：Research paper (scientific journal)  

Forty-four vapor pressures of Refrigerant 152a (CH//3CHF//2: 1,1-difluoroethane) between 273 K and 386 K have been measured in the range of pressures from 0. 26 MPa to 4. 48 MPa. Ten saturated liquid densities and eleven saturated vapor densities near the critical point have also been measured in the range of temperatures from 370 K to the critical temperature which corresponds to a density variation of 153 kg multiplied by (times) m** minus **3 to 635 kg multiplied by (times) m** minus **3. The experimental uncertainties of temperature, pressure and density measurements have been estimated within 10 mK, 0. 8 kPa and 0. 55%, respectively. On the basis of these results, the critical temperature, critical pressure and critical density of R 152a have been determined to be 386. 44 K, 4. 519 8 MPa and 368 kg multiplied by (times) m** minus 3, respectively, in consideration of the meniscus disappearing level as well as the intensity of the critical opalescence.

DOI： 10.1299/jsme1987.30.1106

Language：English   Publishing type：Research paper (scientific journal)  

Measurements of the vapor-liquid coexistence curve in the critical region for the systems of binary refrigerant mixture, i.e., Refrigerant 22 + Refrigerant 114 and Refrigerant 13B1 + Refrigerant 114, have been made by visual observation of the meniscus at the vapor-liquid interface within an optical cell. The experimental uncertainty of the temperature, density, and mass fraction is estimated within 15 mK, 0.5&#37;, and 0.05&#37;, respectively. The critical locus for these mixtures has been determined taking into consideration the disappearing meniscus level and the intensity of the critical opalescence. In accordance with the previous results of the Refrigerant 12 + Refrigerant 22 system, the coexistence curve for binary refrigerant mixtures is discussed. The composition dependence of the critical parameters for refrigerant mixtures is also discussed and compared with that of several predictive methods. © 1986 Plenum Publishing Corporation.

DOI： 10.1007/BF00503796

Language：English   Publishing type：Research paper (scientific journal)  

Measurements of the vapor-liquid coexistence curve in the critical region for the systems of binary refrigerant mixture, i.e., Refrigerant 22 + Refrigerant 114 and Refrigerant 13B1 + Refrigerant 114, have been made by visual observation of the meniscus at the vapor-liquid interface within an optical cell. The experimental uncertainty of the temperature, density, and mass fraction is estimated within 15 mK, 0.5%, and 0.05%, respectively. The critical locus for these mixtures has been determined taking into consideration the disappearing meniscus level and the intensity of the critical opalescence. In accordance with the previous results of the Refrigerant 12 + Refrigerant 22 system, the coexistence curve for binary refrigerant mixtures is discussed. The composition dependence of the critical parameters for refrigerant mixtures is also discussed and compared with that of several predictive methods.

DOI： 10.1007/BF00503796

Language：English   Publishing type：Research paper (scientific journal)  

This paper presents an overview of the thermophysical properties of nonazeotropic refrigerant blends (NARBs) which have been considered prospective especially for the advanced vapor-compression heat pump systems. After introducing some general backgrounds on the thermodynamic behaviors of NARBs, the current state of the art for the thermophysical properties research on NARBs is reviewed. The emphasis, however, is given not only to the systematic studies of thermodynamic properties of NARBs by the group of the present authors at Keio University, Yokohama, but also to the experimental results of non-equilibrium properties recently published in Japan. The paper concludes the importance of thermophysical properties research on refrigerant mixtures under the extended ranges of parameters so as to provide more accurate and concrete criteria to the selection of the optimum blend for various industrial applications.

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Measurements of the vapor-liquid coexistence curve in the critical region for Refrigerant 114 (C//2Cl//2F//4) were made by visual observation of the disppearance of a meniscus at the vapor-liquid interface within an optical cell. Twenty-three saturated densities between 410 K and the critical temperature were obtained in the density range 290 to 894 kg/m**3. The experimental uncertainties of temperature and density were estimated within plus or minus 15 mK and plus or minus 0. 5 %, respectively. On the basis of these results, the critical temperature ** TAU //c and the critical density ** rho //c for R 114 were determined to be 418. 78 K and 576 kg/m**3, respectively, in consideration of the disappearing meniscus level as well as the intensity of the critical opalescence.

DOI： 10.1299/jsme1958.28.2968

Language：English   Publishing type：Research paper (scientific journal)  

The measurements of the vapor-liquid coexistence curve in the critical region for R 114 (C₂Cl₂F₄) were made by visual observation of the disappearance of the meniscus at the vapor-liquid interface within an optical cell. Twenty-three saturated densities between 410 K and critical temperature were obtained in the range of densities 290 to 894 kg/m³. The experimental errors of temperature and density were estimated within ±15mK and ±0.5%, respectively. On the basis of these results, the critical temperature T_c and the critical density ρ_c for R 114 were determined to be 418.78 K and 576 kg/m³, respectively, in consideration of the disappearing meniscus level as well as the intensity of the critical opalescence. The critical pressure P_c for R 114 was calculated to be 3.252 MPa by the available vapor-pressure correlation with the present value of T_c. In addition, the critical exponent β and the law of rectilinear diameter near the critical point were also discussed.

DOI： 10.1299/kikaib.51.1327

Language：English   Publishing type：Research paper (scientific journal)  

Measurements of the vapor-liquid coexistence curve in the critical region for Refrigerant 13B1 (CBrF//3) were made by visual observation of the disappearance of the meniscus at the vapor-liquid interface within an optical cell. Twenty-two saturated densities for temperatures between 332 and 340 K were obtained in the range of densities 376 to 1108 kg/m**3. Based upon the results along the coexistence curve, the critical temperature T//c, the critical density P//c and the critical pressure P//c for R 13B1 were determined to be 340. 08 K, 764 kg/m**3 and 3. 956 MPa, respectively, in consideration of the disappearing meniscus level as well as the intensity of the critical opalescence. In addition, the critical exponent beta was determined to be 0. 340 and the correlation of the vapor-liquid coexistence curve for R 13B1 was established.

DOI： 10.1299/jsme1958.28.2660

Language：English   Publishing type：Research paper (scientific journal)  

The vapor-liquid coexistence curve for refrigerant 502 (R 502) near the critical point has been determined by visual observation of the disappearance of the meniscus. Twenty-six saturated densities between 262 and 899 kg· m-3 have been obtained within an experimental error in temperature and density of ± 10 mK and ± 0.5&#37;, respectively. Using these results along the vapor-liquid coexistence curve, the critical parameters, i.e., the critical temperature Tc=355.37 ±0.01 K and the critical density ρc=555±3kg · m-3, have been determined based on the disappearance of the meniscus level as well as on the intensity of the critical opalescence. A critical pressure Pc=4.070±0.002 MPa has been calculated from the existing vapor-pressure correlation using the present Tcvalue. In addition, the critical exponent β along the coexistence curve and the law of rectilinear diameter near the critical point are discussed. © 1984 Plenum Publishing Corporation.

DOI： 10.1007/BF00505495

Language：English   Publishing type：Research paper (scientific journal)  

The vapor-liquid coexistence curve for refrigerant 502 (R 502) near the critical point has been determined by visual observation of the disappearance of the meniscus. Twenty-six saturated densities between 262 and 899 kg· m^-3 have been obtained within an experimental error in temperature and density of ± 10 mK and ± 0.5%, respectively. Using these results along the vapor-liquid coexistence curve, the critical parameters, i.e., the critical temperature T_c=355.37 ±0.01 K and the critical density ρ_c=555±3kg · m^-3, have been determined based on the disappearance of the meniscus level as well as on the intensity of the critical opalescence. A critical pressure P_c=4.070±0.002 MPa has been calculated from the existing vapor-pressure correlation using the present T_cvalue. In addition, the critical exponent β along the coexistence curve and the law of rectilinear diameter near the critical point are discussed.

DOI： 10.1007/BF00505495

Language：English   Publishing type：Research paper (scientific journal)  

Measurements of the vapor-liquid coexistence curve In the critical region for the binary dichlorodlfluoromethane (CCI2F2, R12) + chlorodlfluoromethane (CHCIF2, R22) system were made by visual observation of the disappearance of the meniscus at the vapor-liquid Interface within an optical cell. Fifty-one saturated-vapor densities and thirty-seven saturated-liquid densities for seven different compositions of 0, 10, 20, 30, 50, 75, and 100 wt &#37; R22 between 355 and 385 K (T, > 0.98) were obtained In the range of densities 280-892 kg/m3 (0.5 < p, < 1.5). The experimental error of temperature, density, and mass fraction was estimated within ±10 mK, ±0.5&#37; and ±0.05 &#37;, respectively. The composition dependence of the critical parameters Is analyzed and discussed on the basis of these measurements. © 1984, American Chemical Society. All rights reserved.

DOI： 10.1021/je00035a012

Language：English   Publishing type：Research paper (scientific journal)  

Measurements of the vapor-liquid coexistence curve In the critical region for the binary dichlorodlfluoromethane (CCI₂F₂, R12) + chlorodlfluoromethane (CHCIF₂, R22) system were made by visual observation of the disappearance of the meniscus at the vapor-liquid Interface within an optical cell. Fifty-one saturated-vapor densities and thirty-seven saturated-liquid densities for seven different compositions of 0, 10, 20, 30, 50, 75, and 100 wt % R22 between 355 and 385 K (T, > 0.98) were obtained In the range of densities 280-892 kg/m³ (0.5 < p, < 1.5). The experimental error of temperature, density, and mass fraction was estimated within ±10 mK, ±0.5% and ±0.05 %, respectively. The composition dependence of the critical parameters Is analyzed and discussed on the basis of these measurements.

DOI： 10.1021/je00035a012

Language：English   Publishing type：Research paper (scientific journal)  

An apparatus and procedures to determine the critical parameters and the vapor-liquid coexistence curve in the critical region by observing the disappearance of the vapor-liquid interface are described. The apparatus has the advantage of measuring the saturated vapor and liquid densities with only a single filling of the sample, and the procedures are applicable not only to pure fluids but also to mixtures. Three densities of liquid and eight of vapor on the coexistence curve for trifluoromethane are obtained, and the critical temperature, density, and pressure are also determined.

DOI： 10.1063/1.1137208

Language：English   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese  

Language：Japanese  

Language：English  

Language：Japanese  

Language：Japanese  

Language：English  

Language：English  

Language：English  

Language：Japanese  

Language：Japanese  

Language：Japanese  

Language：Japanese  

Event date： 2019.9

Language：Japanese  

Venue：東京都江東区   Country：Japan  

Event date： 2019.9

Language：Japanese  

Venue：東京都江東区   Country：Japan  

Event date： 2019.9

Language：Japanese  

Venue：東京都江東区   Country：Japan  

Event date： 2019.8

Language：English  

Venue：Montreal   Country：Canada  

PvTx properties of a binary mixture of 50 mass&#37; HFO1123 (trifluoroethene) + 50 mass&#37; HFO1234yf (2,3,3,3-tetrafluoroprop-1-ene) were measured in the temperature range from 294 to 410 K, in the density range between 83 kg.m^-3 and 905 kg.m^-3, and at pressures up to 8.1 MPa by an isochoric method, and the obtained data are compared with an equation of state (EOS) compiled in REFPROP 10.0. In addition, the critical parameters and saturated densities of the mixture were measured. Vapor-liquid equilibrium of HFO1123 + HFO1234yf was also measured at temperatures from 273 to 313 K by a recirculation method, and the binary interaction parameter of a cubic EOS was determined.

Event date： 2019.8

Language：English  

Venue：Montreal   Country：Canada  

In this work, the calculated surface tension of selected new low GWP (global warming potential) pure compound refrigerants HFO (hydro-fluoro-olefin) is presented. Molecular simulation methods are used to calculate the surface tension of R-1123 (trifluoroethylene) and of R-1234ze(E) (trans-1,3,3,3-tetrafluoroprop-1-ene), as well as densities at saturation. The results obtained by molecular simulation are compared with recent experimental data.

Event date： 2019.8

Language：English  

Venue：Montreal   Country：Canada  

LNG (Liquefied Natural Gas) vaporizer is widely used all over the world to vaporize LNG by using seawater, etc. as a heating source. Intermediated Fluid type LNG Vaporizer (IFV) is using intermediated fluid between LNG and heating source. Propane has been used as an intermediated fluid conventionally, but new refrigerants except for propane are required because usage environment was diversified recently. In this study, refrigerants substitute for propane applicable to IFV were selected as R32 and R410A. On the basis of some experimental formula, prediction of boiling and condensation heat exchange quantity in tube bundles was also carried out and it enabled to predict actual IFV vaporization quantity with plus or minus 2 percent accuracy. The prediction demonstrated that those selected refrigerants can increase the vaporization rate with IFV from the base line of propane.

Event date： 2019.8

Language：English  

Venue：Montreal   Country：Canada  

In this work, the surface tensions of some selected new low GWP (global warming potential) refrigerant mixtures containing HFOs (hydrofluoroolefins) were determined. The surface tension of the HFO-1123/HFC-32 was experimentally determined at temperatures from 265 K to near the critical points and with various compositions. Further, a model associating a cubic equation of state with the linear gradient theory was developed. Good agreement was observed between the experimentally obtained results and those obtained using the developed model.

Event date： 2019.8

Language：English  

Venue：Montreal, Qc   Country：Canada  

Other Link： https://icr2019.org

Event date： 2019.8

Language：English  

Venue：Montreal, Qc   Country：Canada  

Other Link： https://icr2019.org

Event date： 2019.8

Language：English  

Venue：Montreal, Qc   Country：Canada  

Other Link： https://icr2019.org

Event date： 2019.6

Language：English  

Venue：Nago   Country：Japan  

Other Link： https://www.jsme.or.jp/env/iwee/2019

Event date： 2018.12

Language：Japanese  

Venue：兵庫県神戸市   Country：Japan  

Event date： 2018.11

Language：Japanese  

Venue：愛知県名古屋市   Country：Japan  

Event date： 2018.9

Language：English  

Venue：Birmingham   Country：United Kingdom  

By a differential capillary rise method, liquid-vapor interface surface tension was measured for new candidates of next generation refrigerant HFO-1123 and HCFO-1224yd(Z) at temperatures from 266 K to 304 K and from 266 K to 340 K, respectively. The repeatability and reproducibility of the measurement method were checked with HFC-134a and HFC-32. The propagated uncertainty in surface tension was estimated to be within ±0.2 mNm^-1. Based on the measured data, the Van der Waals type empirical correlations were proposed for HFO-1123 and HCFO-1224yd(Z), those are associated with the critical temperatures reported by Higashi and Akasaka. These empirical correlations agree with the measured surface tension data within the measurement uncertainty in the tested temperature range.

Event date： 2018.9

Language：English  

Venue：Birmingham   Country：United Kingdom  

The first fundamental equation of state for HCFO-1224yd(Z) was published in 2017. This equation shows reasonable accuracies in the density and vapor pressure at moderate temperatures and pressures. In addition, this equation is designed to exhibit physically correct behavior in extrapolated regions. At high temperatures and pressures, however, uncertainties in calculated properties would be higher, because at this time available experimental data are limited to restricted ranges. This paper demonstrates comparisons of the current equation to some available experimental data and evaluates behavior of the equation in the extrapolated regions.

Event date： 2018.9

Language：English  

Venue：Birmingham   Country：United Kingdom  

Other Link： https://ior.org.uk/events/hfo2018

Event date： 2018.9

Language：English  

Venue：Birmingham   Country：United Kingdom  

Event date： 2018.7

Language：English  

Venue：Purdue, West Lafayette   Country：United States  

Other Link： https://engineering.purdue.edu/Herrick/Conferences/2018/2018_HLPurdueConferences_Program.pdf

Event date： 2018.7

Language：English  

Venue：Purdue, West Lafayette   Country：United States  

Other Link： https://engineering.purdue.edu/Herrick/Conferences/2018/2018_HLPurdueConferences_Program.pdf

Event date： 2018.6

Language：English  

Venue：Sapporo, Hokkaido   Country：Japan  

The global warming is now one of the serious international concern should be tackled worldwide. HFC refrigerants, such as R410A, are categorized as the long lived green-house gasses. This paper presents the surface tension measurement data of HFO-1123 with GWP less than 1, and a binary mixture HFO-1123/HFC-32. The capillary constant and surface tension of those are measured across temperature range from 267 K to 307 K by a differential capillary rise with a propagated uncertainty ±0.3 mN m^-1. Among the selected predicting methods, the correlations of Di Nicola et al. (2011) and Gharagheizi et al. (2012) show the best agreement to the measured surface tension of HFO-1123 alone. For HFO-1123/HFC-32, the correlation of Di Nicola et al. (2017) shows good agreement. To predict the surface tension HFO-1123/HFC-32, empirical correlation is proposed based on the measured data.

Event date： 2018.6

Language：English   Presentation type：Oral presentation (general)  

Venue：Sapporo   Country：Japan  

Other Link： http://www.acra2018.org/

Event date： 2018.6

Language：English  

Venue：Sapporo   Country：Japan  

Other Link： http://www.acra2018.org/

Event date： 2017.11

Language：Japanese  

Venue：つくば   Country：Japan  

Event date： 2017.11

Language：Japanese  

Venue：つくば   Country：Japan  

Event date： 2017.9

Language：Japanese  

Venue：東京   Country：Japan  

Event date： 2017.9

Language：Japanese  

Venue：東京   Country：Japan  

Event date： 2017.9

Language：Japanese  

Venue：東京   Country：Japan  

Event date： 2017.9

Language：English  

Venue：Graz   Country：Austria  

Event date： 2017.5

Language：English  

Venue：Seoul   Country：Korea, Republic of  

Event date： 2016.12

Language：English  

Venue：Kobe   Country：Japan  

Event date： 2016.12

Language：English   Presentation type：Oral presentation (general)  

Venue：神戸   Country：Japan  

Event date： 2016.11

Language：Japanese  

Venue：Okayama   Country：Japan  

Event date： 2016.10

Language：English   Presentation type：Oral presentation (general)  

Venue：Yokohama   Country：Japan  

Event date： 2016.9

Language：Japanese  

Venue：徳島大学   Country：Japan  

Event date： 2016.7

Language：English  

Venue：Purdue   Country：United States  

Event date： 2015.10

Language：Japanese  

Venue：東京   Country：Japan  

Event date： 2015.9

Language：English   Presentation type：Symposium, workshop panel (public)  

Venue：Yokohama   Country：Japan  

Event date： 2015.9

Language：English   Presentation type：Symposium, workshop panel (public)  

Venue：I2CNER, Kyushu University, Fukuoka   Country：Japan  

Event date： 2015.8

Language：English  

Venue：Yokohama   Country：Japan  

Measurements of PρTx properties, saturated densities and critical parameters for low GWP refrigerant mixtures of 50.00 mass&#37; R1234yf (2, 3, 3, 3-tetrafluoroprop-1-ene; CF₃CF=CH₂) + 50.00 mass&#37; R1234ze(E) (trans-1, 3, 3, 3-tetrafluoroprop-1-ene; CF₃CH=CHF) system were measured with two types of isochoric methods. As for PρTx properties, 5 isochores were obtained in the range of temperatures from 310 K to 430 K, of pressures from 837 kPa to 6774 kPa, and of densities from 100 kg·m^-3 to 900 kg·m^-3. As for the saturated densities, 9 saturated vapor densities and 6 saturated liquid densities were measured for temperatures from 354.622 K to 374.280 K and for densities between 219 kg·m^-3 and 870 kg·m^-3. On the basis of the present data, the critical temperature T_c = 374.28 K, critical density ρ_c = 480 kg·m^-3, and critical pressure P_c = 3524 kPa for 50&#37; R 1234yf + 50&#37; R 1234ze(E) mixture were determined by the direct observation of meniscus disappearance.

Event date： 2015.8

Language：English  

Venue：Yokohama   Country：Japan  

R1234ze(Z) and R1233zd(E) are very recently under consideration as a potential candidate to replace R245fa that is widely used in organic Rankine cycles and high-temperature industrial heat pumps. The capillary constant and surface tension of saturated R1234ze(Z) and R1233zd(E) were measured across the temperature range from 274 K to 350 K using a measuring apparatus based on the differential capillary rise method. The measurement uncertainty in the surface tension was typically 0.3 mN m^-1. The experimental surface tension was well represented by a van der Waals type equation expressing the temperature dependence as, ω= 59.90 (1 - T_r)^1.237 for R245fa, ω= 56.57 (1 - T_r) ^1.220 for R1234ze(Z), and ω= 61.95 (1 - T_r) ^1.277 for R1233zd(E), where, ω and T_r are the surface tension in mNm^-1 and the reduced temperature, T_r = T/T_crit. The critical temperatures T_crit are given as 427.01 K for R245fa, 423.27 K for R1234ze(Z) by Higashi et al. (2015), and 438.75 K for R1233zd(E) by Hulse et al. (2012). The constants and exponents are empirically determined by the least square mean method. The above correlations represent the experimental surface tension within ±0.13, ±0.21 mN m¹, and ±0.05 mN m^-1 for R245fa, R1234ze(Z), and R1233zd(E), respectively.

Event date： 2015.8

Language：English  

Venue：Yokohama   Country：Japan  

Event date： 2015.8

Language：English  

Venue：Yokohama   Country：Japan  

Event date： 2015.6

Language：English  

Venue：Boulder, Colorado   Country：United States  

Event date： 2015.6

Language：English  

Venue：Boulder, Colorado   Country：United States  

Event date： 2015.6

Language：English  

Venue：Boulder, Colorado   Country：United States  

Event date： 2015.6

Language：English  

Venue：Boulder, Colorado, USA   Country：United States  

Event date： 2015.4

Language：Japanese  

Venue：東京   Country：Japan  

Event date： 2014.12

Language：English   Presentation type：Symposium, workshop panel (public)  

Venue：Padova   Country：Italy  

Event date： 2014.11

Language：Japanese  

Venue：東京   Country：Japan  

Event date： 2014.11

Language：Japanese  

Venue：東京   Country：Japan  

Event date： 2014.9

Language：Japanese  

Venue：佐賀   Country：Japan  

Event date： 2014.9

Language：Japanese  

Venue：佐賀   Country：Japan  

Event date： 2014.7

Language：English  

Venue：Purdue University   Country：United States  

Event date： 2014.5

Language：English  

Venue：Jeju Island   Country：Korea, Republic of  

The determination of the critical parameters as well as the measurements of vapor pressures was made for 1,1,1,3,3-pentafluoropropane (R 245fa: C₃H₃F₅). The critical temperature and critical density of R 245fa were determined by the direct observation of meniscus disappearance in consideration of the intensity of critical opalescence and meniscus disappearing level. The measurements of vapor pressures were carried out by the isochoric method. As for both of apparatus, temperature was measured with 25 Ω standard platinum resistance thermometer and thermometer bridge with an aid of ITS-90. The digital quartz pressure transducer and pressure indicator were used for the pressure measurements. And density was calculated from the sample mass and inner volume of pressure vessel. The experimental uncertainties of temperature, pressure, and density measurements are estimated within 20 mK, 1 kPa, and 0.1&#37;, respectively. Twenty-nine vapor pressure data for R 245fa were obtained in the temperature range from 310 K to the critical temperature and pressure up to 3.59 MPa with individual two runs. On the basis of these vapor-pressure measurements, the correlation of vapor pressures was proposed. The comparison with the vapor-pressure data reported by other investigators was also made. The authors are greatly indebted to Kobe Steel Ltd., Japan, for financial support, and to Asahi Glass Co., Japan, for furnishing and analyzing the high purity sample. The authors greatly thank to Messrs S. Hayasaka, C. Shirai, and Y. Oohira who are the student of Iwaki Meisei University, for their valuable assistance in the experiment. This work was supported by Grant-in-Aid for Scientific Research (C) 24560240 and 24560243 from Japan Societry for the Promotion of Science.

Event date： 2014.5

Language：English  

Venue：Juju   Country：Korea, Republic of  

Event date： 2013.11 - 2019.11

Language：Japanese  

Venue：名古屋   Country：Japan  

Event date： 2013.11

Language：Japanese  

Venue：名古屋   Country：Japan  

Event date： 2013.11

Language：Japanese  

Venue：富山   Country：Japan  

Event date： 2013.11

Language：Japanese  

Venue：東京   Country：Japan  

Event date： 2013.11

Language：Japanese  

Venue：東京   Country：Japan  

Event date： 2013.9

Language：Japanese  

Venue：東京   Country：Japan  

Event date： 2013.6

Language：English  

Venue：Delft   Country：Netherlands  

Event date： 2013.6

Language：English  

Venue：Delft   Country：Netherlands  

Event date： 2012.11 - 2012.12

Language：Japanese  

Venue：大阪   Country：Japan  

Event date： 2012.11

Language：Japanese  

Venue：熊本   Country：Japan  

Event date： 2012.10

Language：Japanese  

Venue：大阪   Country：Japan  

Event date： 2012.9

Language：Japanese  

Venue：北海道   Country：Japan  

Event date： 2012.6

Language：English  

Venue：Boulder, Colorado   Country：United States  

Event date： 2012.6

Language：English  

Venue：Boulder, Colorado   Country：United States  

Event date： 2011.11

Language：Japanese  

Venue：横浜   Country：Japan  

Event date： 2011.11

Language：Japanese  

Venue：横浜   Country：Japan  

Event date： 2011.10

Language：English  

Venue：Prague   Country：Czech Republic  

Event date： 2011.10

Language：English  

Venue：Prague   Country：Czech Republic  

Event date： 2011.9

Language：Japanese  

Venue：東京   Country：Japan  

Event date： 2010.11 - 2019.11

Language：Japanese  

Venue：福岡   Country：Japan  

Event date： 2010.11

Language：Japanese  

Venue：福岡   Country：Japan  

Event date： 2010.10

Language：English  

Venue：Tokyo   Country：Japan  

Event date： 2010.9

Language：Japanese  

Venue：金沢   Country：Japan  

Event date： 2010.9

Language：Japanese  

Venue：金沢   Country：Japan  

Event date： 2010.9

Language：Japanese   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：Tokyo   Country：Japan  

Event date： 2010.6

Language：English  

Venue：Tokyo   Country：Japan  

The surface tension of mixtures including low GWP refrigerants, 50 mass &#37; HFO-1234yf/50 mass &#37; HFC-32 and 50 mass &#37; HFO-1234ze(E)/50 mass &#37; HFC-32, was measured by the differential capillary-rise method in the temperature range from 273 K to 323 K. On a basis of the present data, correlations were formulated as a function of temperature by the expression of van der Waals type. A mixing rule for the coefficients in correlations of pure components was discussed for representing the data of mixtures. It is found to be difficult for representing the data of mixtures by a simple mixing rule.

Event date： 2010.5

Language：Japanese  

Venue：Tokyo   Country：Japan  

Event date： 2010.4

Language：Japanese  

Venue：東京   Country：Japan  

Event date： 2010.2

Language：English  

Venue：Tokyo   Country：Japan  

Event date： 2010.2

Language：English  

Venue：Tokyo   Country：Japan  

Event date： 2009.10

Language：Japanese  

Venue：米沢   Country：Japan  

Event date： 2009.10

Language：Japanese  

Venue：米沢   Country：Japan  

Event date： 2009.10

Language：Japanese  

Venue：東京   Country：Japan  

Event date： 2009.10

Language：Japanese  

Venue：東京   Country：Japan  

Event date： 2009.7

Language：Japanese  

Venue：沖縄   Country：Japan  

Event date： 2009.6

Language：English  

Venue：Boulder, Denver   Country：United States  

Event date： 2009.6

Language：English  

Venue：Boulder, Colorado   Country：United States  

Event date： 2009.6

Language：English  

Venue：Boulder, Colorado   Country：United States  

Event date： 2009.6

Language：English  

Venue：Boulder, Colorado   Country：United States  

Event date： 2009.6

Language：English  

Venue：Boulder, Colorado   Country：United States  

Event date： 2009.4

Language：Japanese  

Venue：東京   Country：Japan  

Event date： 2009.4

Language：Japanese  

Venue：東京   Country：Japan  

Event date： 2009.4

Language：Japanese  

Venue：東京   Country：Japan  

Event date： 2008.10

Language：Japanese  

Venue：東京   Country：Japan  

Event date： 2008.5

Language：English  

Venue：Copenhagen   Country：Denmark  

Event date： 2008.3

Language：Japanese  

Country：Japan  

Event date： 2007.11

Language：Japanese  

Venue：長岡   Country：Japan  

Event date： 2007.11

Language：English  

Venue：Beijing   Country：China  

Event date： 2007.10

Language：Japanese  

Venue：札幌   Country：Japan  

Event date： 2007.10

Language：Japanese  

Venue：東京農工大学   Country：Japan  

Event date： 2006.10

Language：Japanese  

Venue：福岡   Country：Japan  

Event date： 2006.10

Language：Japanese  

Venue：福岡   Country：Japan  

Event date： 2006.10

Language：Japanese  

Venue：京都   Country：Japan  

Event date： 2006.8

Language：Japanese  

Country：Japan  

Event date： 2006.6

Language：English  

Venue：Boulder, Colorado   Country：United States  

Event date： 2006.6

Language：English  

Venue：Boulder, Colorado   Country：United States  

Event date： 2006.5

Language：English  

Venue：Gyeongju   Country：Korea, Republic of  

The surface tension of the R290 + R600a mixture has been measured by the differential capillary-rise method. For measuring the binary system, the apparatus was modified to determine the composition of the sample. Seventeen data with a change of composition were obtained at 278.28 K. The experimental uncertainties of temperature and surface tension measurements are estimated to be within 20 mK and 0.2 mN·m^-1, respectively. The present data are compared with REFPROP ver.7.0 calculations [1]. As for composition dependence, the present data show different behavior against to REFPROP ver.7.0 calculations. Three kinds of mixing rules were tested for representing the composition dependence of the present data. It is found the simple mixing rule by mole fraction is effective for the R290 + R600a mixture.

Event date： 2006.3

Language：English  

Venue：Gyeongju   Country：Korea, Republic of  

Event date： 2006.3

Language：Japanese  

Venue：福島   Country：Japan  

Event date： 2006.3

Language：Japanese  

Venue：福島   Country：Japan  

Event date： 2006.3

Language：Japanese  

Venue：福島   Country：Japan  

Event date： 2005.11

Language：Japanese  

Venue：つくば   Country：Japan  

Event date： 2005.9

Language：English  

Venue：Vicenza   Country：Italy  

Event date： 2005.3

Language：Japanese  

Venue：宮城   Country：Japan  

Event date： 2004.10

Language：Japanese  

Venue：浜松   Country：Japan  

Event date： 2004.10

Language：Japanese  

Venue：長野   Country：Japan  

Event date： 2004.10

Language：English  

Venue：Glasgow   Country：United Kingdom  

Event date： 2004.10

Language：English  

Venue：Glasgow   Country：United Kingdom  

Event date： 2003.10

Language：Japanese  

Venue：岡山   Country：Japan  

Event date： 2003.9

Language：English  

Venue：Boulder, Colorado   Country：United States  

Event date： 2003.5

Language：English  

Venue：Sendai   Country：Japan  

Event date： 2002.11

Language：Japanese  

Venue：東京   Country：Japan  

Event date： 2002.11

Language：Japanese  

Venue：岡山   Country：Japan  

Event date： 2002.11

Language：Japanese  

Venue：岡山   Country：Japan  

Event date： 2002.7

Language：English  

Venue：Purdue University   Country：United States  

Event date： 2001.11

Language：Japanese  

Venue：仙台   Country：Japan  

Event date： 2001.9

Language：English  

Venue：Paderborn   Country：Germany  

Event date： 2000.10

Language：Japanese  

Venue：名古屋   Country：Japan  

Event date： 2000.6

Language：English  

Venue：Boulder, Colorado   Country：United States  

Event date： 2000.6

Language：English  

Venue：Boulder, Colorado   Country：United States  

Event date： 1997.6

Language：English  

Venue：Boulder, CO, USA   Country：Other  

The surface tension of several refrigerant mixtures was measured and correlated. The measurements were conducted using the differential capillary rise method (DCRM) under conditions of coexistence of the sample liquid and its saturated vapor in equilibrium. The temperature range covered was from 273 to 323 K. The resulting data were represented by a mixing rule using mass friction based on the van der Waals correlation.

Event date： 1997.6

Language：English  

Venue：Boulder, Colorado   Country：United States  

Event date： 1997.6

Language：English  

Venue：Boulder, Colorado   Country：United States  

Event date： 1996.11

Language：Japanese  

Venue：筑波   Country：Japan  

Event date： 1996.11

Language：Japanese  

Venue：筑波   Country：Japan  

Event date： 1996.11

Language：Japanese  

Venue：筑波   Country：Japan  

Event date： 1996.11

Language：Japanese  

Venue：博多   Country：Japan  

Event date： 1996.11

Language：Japanese  

Venue：博多   Country：Japan  

Event date： 1996.11

Language：Japanese  

Venue：博多   Country：Japan  

Event date： 1996.4

Language：English  

Venue：New Orleans   Country：United States  

Event date： 1995.11

Language：Japanese  

Venue：広島   Country：Japan  

Event date： 1995.11

Language：Japanese  

Venue：広島   Country：Japan  

Event date： 1995.11

Language：Japanese  

Venue：広島   Country：Japan  

Event date： 1995.11

Language：Japanese  

Venue：広島   Country：Japan  

Event date： 1995.9

Language：English  

Venue：Tokyo   Country：Japan  

Event date： 1995.4

Language：English  

Venue：Hague   Country：Netherlands  

Event date： 1995.4

Language：Japanese  

Venue：東京   Country：Japan  

Event date： 1995.4

Language：Japanese  

Venue：東京   Country：Japan  

Event date： 1995.2

Language：English  

Country：Singapore  

Event date： 1994.11

Language：English  

Venue：Padova   Country：Italy  

Event date： 1994.11

Language：Japanese  

Country：Japan  

Event date： 1994.11

Language：English  

Venue：Padova   Country：Italy  

Event date： 1994.10

Language：English  

Venue：富山   Country：Japan  

Event date： 1994.9

Language：English  

Venue：Boulder, Colorado   Country：United States  

Event date： 1994.9

Language：English  

Venue：Boulder, Colorado   Country：United States  

Event date： 1994.4

Language：Japanese  

Venue：東京   Country：Japan  

Event date： 1994.4

Language：Japanese  

Venue：東京   Country：Japan  

Event date： 1994.4

Language：Japanese  

Venue：東京   Country：Japan  

Event date： 1993.11

Language：English  

Venue：横浜   Country：Japan  

Event date： 1993.11

Language：English  

Venue：横浜   Country：Japan  

Event date： 1992.9

Language：English  

Venue：秋田   Country：Japan  

Event date： 1992.9

Language：English  

Venue：秋田   Country：Japan  

Event date： 1991.11

Language：English  

Venue：京都   Country：Japan  

Event date： 1991.2

Language：English  

Venue：Montreal   Country：Canada  

Event date： 1990.11

Language：English  

Venue：東京   Country：Japan  

Event date： 1989.10

Language：English  

Venue：Sapporo   Country：Japan  

Event date： 1987.5

Language：English  

Venue：Wien   Country：Austria  

Event date： 1987.5

Language：English  

Venue：Wien   Country：Austria  

Event date： 1987.4

Language：English  

Venue：Hawaii   Country：United States  

Event date： 1987.4

Language：English  

Venue：Hawaii   Country：United States  

Event date： 1986.10

Language：English  

Venue：筑波   Country：Japan  

Event date： 1986.5

Language：English  

Country：Japan  

Event date： 1985.11

Language：English  

Venue：仙台   Country：Japan  

Event date： 1985.10

Language：Japanese  

Venue：徳島   Country：Japan  

Event date： 1984.3

Language：Japanese   Presentation type：Symposium, workshop panel (public)  

Venue：Erlangen   Country：Germany  

Event date： 1983.9

Language：English   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：Tokyo   Country：Japan  

Event date： 1983.7

Language：English  

Venue：Paris   Country：France  

Language：Japanese  

Country：Japan  

Language：Japanese  

Country：Japan  

Language：Japanese  

Country：Japan  

Language：Japanese  

Country：Japan  

Language：Japanese  

Venue：東京   Country：Japan  

Language：Japanese  

Country：Japan  

Language：English  

Country：Other  

The assessment of the predictive methods of the critical parameters is discussed on the basis of the comparison with the experimental results of our own critical parameters for the binary refrigerant mixtures, i. e. , the R 12(dichlorodifluoromethane; CCl//2F//2) plus R 22 (chlorodifluoromethane; CHClF//2) system, the R 22 plus R 114 (1,2-dichloro-1,1,2,2-tetrafluoroethane; CClF//2CClF//2) system, and the R 13B1 (bromotrifluoromethane; CBrF//3) plus R 114 system. The predictive method by Li for the critical temperature, that by Chueh-Prausnitz for the critical temperature and critical molar volume, that by Kreglewski-Kay for the critical pressure, that by Soave-Redlich-Kwong equation (SRK equation) as well as that by Peng-Robinson equation (PR equation) are discussed. Due to these comparisons, it becomes clear that it is difficult to predict the critical parameters for the binary refrigerant mixtures consistency by the predictive methods ever reported.

Language：English  

Country：Other  

The approach to the generalized representation of vapor-pressure curve is discussed on the basis of the experimental data of vapor pressure for eight halogenated hydrocarbons. With respect to the functional form of the generalized representation of vapor-pressure curve, the Pitzer expansion based on the principle of corresponding states with acentric factor was adopted. The coefficients in the representation have been determined by the least squares fitting to the experimental vapor pressure data for eight halogenated hydrocarbons mentioned above. The proposed generalized representation reproduces most of these data within a pressure deviation of plus or minus 1. 0&#37;.

Language：English  

Country：Other  

Measurements of the vapor-liquid coexistence curve in the critical region have been continued by visual observation of the disappearance of the meniscus at the vapor-liquid interface within an optical cell. The experimental results for dichlorodifluoromethane plus chlorodifluoromethane and chlorodifluoromethane plus 1,2-dichlorotetrafluoroethane systems are presented. The critical locus of these systems is illustrated and the composition dependence of the critical parameters is discussed.

Language：Japanese  

Venue：いわき   Country：Japan