Acoustic determination of ideal-gas heat capacity and second virial coefficients of some refrigerants between 250 and 420 K

Beekermann, W.; Köhler, Friedrich

doi:10.1007/bf01441911

Cited by 39 publications

(20 citation statements)

References 8 publications

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“…The temperature dependence of the second virial coefficients given in Table 3 is represented by B = 4.33476 x 10"1 + 6.09455 x 10-1 _1 -4.87858 x 1 exp(Tr_1) (3) where B is given in liters per mole. In Figure 5, the B values by Beckermann and Kohler (1994) obtained from acoustic measurements are compared with eq 3 and the present data. Although the values by Beckermann and Kohler are systematically higher than the present results, the two different measurements show agreement within 2%.…”

Section: Discussionmentioning

confidence: 74%

“…Therefore, it has recently been proposed to use this substance in refrigeration applications as a component of promising alternative refrigerant mixtures with other HFC refrigerants such as difluoromethane (R-32), pentafluoroethane (R-125), and/or 1,1,1,2tetrafluoroethane (R-134a). Concerning its thermodynamic properties, vapor pressures and second virial coefficients were reported in the literature (Beckermann and Kohler, 1994;Fukushima, 1993;Russell et al, 1944;Widiatmo et al, 1994;Ye, 1993), but very few PVT results are available.…”

mentioning

confidence: 99%

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Vapor Pressures, Gas-Phase PVT Properties, and Second Virial Coefficients for 1,1,1-Trifluoroethane

Zhang¹,

Sato²,

Watanabe³

1995

J. Chem. Eng. Data

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The PVT properties of 1,1,1-trifluoroethane (R-143a) in the gas phase have been measured by a Burnett apparatus in the range of temperatures from 320 to 380 K and at pressures up to 6 MPa. The vapor pressures in the range of temperatures from 295 to 342 K have also been measured, and a vapor-pressure correlation has been developed. The critical pressure was determined to be (3.776 ± 0.005) MPa on the basis of the present measurements. The second virial coefficients have been determined along seven isotherms, and a truncated virial equation of state has also been developed to represent the temperature dependence of the second virial coefficients and the present Burnett PVT measurements. The experimental uncertainties of temperature, pressure, density, and second virial coefficient throughout the present study were estimated to be no more than ±8 mK, ±0.8 kPa, ±0.12%, and ±5%, respectively. The purity of the R-143a sample used was better than 99.95 mol %.

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Section: Discussionmentioning

confidence: 74%

mentioning

confidence: 99%

Vapor Pressures, Gas-Phase PVT Properties, and Second Virial Coefficients for 1,1,1-Trifluoroethane

Zhang¹,

Sato²,

Watanabe³

1995

J. Chem. Eng. Data

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“…For the heat capacity fitting of frequencies, reference heat capacities for 25 compounds were used. All compounds used in the fitting of frequencies on heat capacities are also a part of the enthalpy of formation fitting set.…”

Section: Methodsmentioning

confidence: 99%

Generalized Prediction of Enthalpies of Formation Using DLPNO‐CCSD(T) Ab Initio Calculations for Molecules Containing the Elements H, C, N, O, F, S, Cl, Br

et al. 2019

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The prediction of thermochemical properties such as enthalpies of formation is of crucial importance, both in research and industrial applications, especially for systems involving not well‐characterized molecules, such as biomass systems (bio‐oils), or systems involving new compounds (new‐generation refrigerants). It is highly desirable to obtain an efficient method by which these values can be predicted. Ab initio‐based calculations can be very accurate for predicting gas phase thermochemical properties and are usually more versatile than group contribution methods. In this work, we propose a general extension of the work of Paulechka and Kazakov, using very accurate and efficient domain‐based local pair natural orbital‐coupled cluster theory ab initio calculations, to determine the enthalpies of formation of a broad variety of molecules. New sets of regressed atomic contributions are proposed for a larger group of elements: H, C, N, O, F, S, Cl, and Br. Excellent predictions are obtained for the most studied compounds (bio‐oil compounds and refrigerants). © 2019 Wiley Periodicals, Inc.

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“…Comparisons with their data in the liquid show deviations less than 1 % between (283 and 363) K. The deviations are substantially higher outside of this region. The second virial coefficient data of Beckermann and Kohler (1995) are represented to within about 1.5 %. Other sources show deviations of up to about 5 %.…”

Section: Enthalpy Differencesmentioning

confidence: 99%

Short Fundamental Equations of State for 20 Industrial Fluids

2006

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In a preceding project, functional forms for "short" Helmholtz energy equations of state for typical nonpolar and weakly polar fluids and for typical polar fluids were developed using simultaneous optimization. In this work, the coefficients of these short forms for the equations of state have been fitted for the fluids acetone, carbon monoxide, carbonyl sulfide, decane, hydrogen sulfide, 2-methylbutane (isopentane), 2,2-dimethylpropane (neopentane), 2-methylpentane (isohexane), krypton, nitrous oxide, nonane, sulfur dioxide, toluene, xenon, hexafluoroethane (R-116), 1,1-dichloro-1-fluoroethane (R-141b), 1-chloro-1,1-difluoroethane (R-142b), octafluoropropane (R-218), 1,1,1,3,3-pentafluoropropane (R-245fa), and fluoromethane (R-41). The 12 coefficients of the equations of state were fitted to substance specific data sets. The results show that simultaneously optimized functional forms can be applied to other fluids out of the same class of fluids for which they were optimized without significant loss of accuracy. The high numerical stability of the functional forms resulted in successful fits for fluids that previously could not be described by accurate empirical equations of state. For R-41, it is shown that the accuracies can be increased further by fitting the temperature exponents in addition to the coefficients of the equation of state, provided that highly accurate experimental data are available. Typical uncertainties of properties calculated using the new equations are 0.2 % in density, 1 % to 2 % in heat capacity and liquid-phase speed of sound, and 0.2 % in vapor pressure. Where data are available, uncertainties in vapor-phase sound speeds are generally less than 0.1 %.

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Acoustic determination of ideal-gas heat capacity and second virial coefficients of some refrigerants between 250 and 420 K

Cited by 39 publications

References 8 publications

Vapor Pressures, Gas-Phase PVT Properties, and Second Virial Coefficients for 1,1,1-Trifluoroethane

Vapor Pressures, Gas-Phase PVT Properties, and Second Virial Coefficients for 1,1,1-Trifluoroethane

Generalized Prediction of Enthalpies of Formation Using DLPNO‐CCSD(T) Ab Initio Calculations for Molecules Containing the Elements H, C, N, O, F, S, Cl, Br

Short Fundamental Equations of State for 20 Industrial Fluids

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