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  • 1
    Electronic Resource
    Electronic Resource
    Measurements ofPVTx properties of refrigerant mixture HFC-32+HFC-125 in the gaseous phase (1996)
    Springer
    International journal of thermophysics 17 (1996), S. 43-54 
    Details
    ISSN: 1572-9567
    Keywords: alternative refrigerant ; binary refrigerant mixtures ; HFC-32+HFC-125 system ; PVTx properties ; thermodynamic properties ; virial coefficients
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The experimental 156PVTx properties of an important binary refrigerant mixture, HFC-32 (difluoromethane)+HFC-125 (pentafluorethane), have been measured for three compositions, i.e., 50, 60, and 80 wt% HFC-32, by a constant-mass-method coupled with expansion procedure in an extensive range of temperaturesT from 320 to 440 K, of pressuresP from 1.8 to 5.3 M Pa, and of densities p from 50 to 124 kg · m−3. The experimental uncertainties of the present measurements are estimated to be within ±7 mK in temperature, ±2 kPa in pressure, ±0.2% in density and ±0.02 wt% of HFC-32. The sample purities are 99.998 wt% for HFC-32 and 99.99 wt% for HFC-125. Seventy-eight second and third virial coeflicients for temperatures from 320 to 440 K have been determined by the present measurements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01448208
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  • 2
    Electronic Resource
    Electronic Resource
    Ideal-gas specific heat and second virial coefficient of HFC-125 based on sound-velocity measurements (1996)
    Springer
    International journal of thermophysics 17 (1996), S. 587-595 
    Details
    ISSN: 1572-9567
    Keywords: alternative refrigerant ; HFC-125 ideal-gas specific heat ; second acoustic-virial coefficient ; second virial coefficient ; sound velocity ; spherical resonator
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The sound velocity in gaseous pentafluoroethane (HFC-125, CF3CHF2) has been measured by means of a spherical acoustic resonator, Seventy-two sound-velocity values were measured with an uncertainty of ±0.01% at temperatures from 273 to 343 K and pressures from 101 to 250 kPa. The ideal-gas specific heats and the second acoustic-virial coefficients have been determined on the basis of the Sound-velocity measurements. The second virial coefficients calculated from the present sound-velocity measurements agree with literature values which were determined fromPVT measurements by means of a Burnett method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01441505
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  • 3
    Electronic Resource
    Electronic Resource
    Bubble-Point Pressures and Saturated- and Compressed-Liquid Densities of the Binary R-125 + R-143a System (1999)
    Springer
    International journal of thermophysics 20 (1999), S. 911-922 
    Details
    ISSN: 1572-9567
    Keywords: alternative refrigerant ; binary R-125 + R-143a mixtures ; bubble-point pressure ; compressed-liquid density ; R-125 ; R-143a ; saturated-liquid density ; vapor-liquid equilibria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Bubble-point pressures and saturated- and compressed-liquid densities of the binary R-125 (pentafluoroethane) + R-143a (1,1,1 -trifluoroethane) system have been measured for several compositions at temperatures from 280 to 330 K by means of a magnetic densimeter coupled with a variable-volume cell mounted with a metallic bellows. The experimental uncertainties of the temperature, pressure, density, and composition were estimated to be within ±10mK, ± 12 kPa, ±0.2%, and ±0.2mass%, respectively. The purities of the samples used throughout the measurements are 99.96 area% for R-125 and 99.94 area% for R-143a. Based on these measurements, the thermodynamic behavior of the vapor-liquid equilibria of this binary refrigerant mixture has been represented using the Peng–Robinson equation for the bubble-point pressures, a correlation for the saturated-liquid densities, and an equation of state for the compressed-liquid densities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022643404972
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  • 4
    Electronic Resource
    Electronic Resource
    An Equation of State for 1,1,1-Trifluoroethane (R-143a) (1999)
    Springer
    International journal of thermophysics 20 (1999), S. 1639-1651 
    Details
    ISSN: 1572-9567
    Keywords: alternative refrigerant ; equation of state ; Helmholtz energy ; R-143a ; 1,1,1-trifluoroethane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A fundamental equation of state has been developed for 1,1,1-trifluoroethane (R-143a) using the dimensionless Helmholtz energy. The experimental thermodynamic property data, which cover temperatures from the triple point (161 K) to 433 K and pressures up to 35 MPa, are used to develop the present equation. These data are represented by the present equation within their reported experimental uncertainties: ±0.1% in density for both vapor and liquid phase P–ρ–T data, ±1% in isochoric specific heat capacities, and ±0.02% in the vapor phase speed-of-sound data. The extended range of validity of the present model covers temperatures from 160 to 650 K and pressures up to 50 MPa as verified by the thermodynamic behavior of the isobaric heat-capacity values over the entire fluid phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022645626800
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  • 5
    Electronic Resource
    Electronic Resource
    Determination of Second Virial Coefficients and Virial Equations of R-32 (Difluoromethane) and R-125 (Pentafluoroethane) Based on Speed-of-Sound Measurements (1999)
    Springer
    International journal of thermophysics 20 (1999), S. 1677-1688 
    Details
    ISSN: 1572-9567
    Keywords: alternative refrigerant ; equation of state ; hydrofluorocarbon ; R-32 ; R-125 ; second virial coefficient ; speed of sound
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The second virial coefficients, B, for difluoromethane (R-32, CH2F2) and pentafluoroethane (R-125, CF3CHF2) are derived from speed-of-sound data measured at temperatures from 273 to 343 K with an experimental uncertainty of ±0.0072%. Equations for the second virial coefficients were established, which are valid in the extensive temperature ranges from 200 to 400 K and from 240 to 440 K for R-32 and R-125, respectively. The equations were compared with theoretically derived second virial coefficient values by Yokozeki. A truncated virial equation of state was developed using the determined equation for the virial coefficients. The virial equation of state represents our speed-of-sound data and most of the vapor PρT data measured by deVries and Tillner-Roth within ±0.01 and ±0.1%, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022601811779
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