### Abstract

We developed a fundamental equation of state for pentafluoroethane (R-125, CHF_{2}CF_{3}) which is represented in terms of a non-dimensional Helmholtz free energy. The equation has been established on the basis of selected measurements of the pressure-density-temperature relation, speed of sound, heat capacities, and saturation properties. Linear and non-linear regression analysis was employed to determine the functional form and the numerical parameters. The equation represents all the thermodynamic properties of R-125 in the liquid and gaseous phases for temperatures between the triple point and 470 K, and pressures up to 35 MPa. The uncertainties are estimated to be about ±0.05% or 0.1 kPa for the vapor pressure, ±0.05% for the liquid and vapor densities, about ±1% for the isobaric and isochoric heat capacities in the liquid, and ±0.5% or ±0.02% for the speed of sound in the liquid and vapor, respectively.

Original language | English |
---|---|

Pages (from-to) | 1623-1635 |

Number of pages | 13 |

Journal | International Journal of Thermophysics |

Volume | 19 |

Issue number | 2-6 |

Publication status | Published - 1998 Nov |

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### Keywords

- Equation of state
- HFCs
- Pentafluoroethane
- R-125
- Refrigerant
- Thermodynamic properties

### ASJC Scopus subject areas

- Physical and Theoretical Chemistry
- Mechanics of Materials
- Computational Mechanics
- Fluid Flow and Transfer Processes
- Physics and Astronomy (miscellaneous)

### Cite this

*International Journal of Thermophysics*,

*19*(2-6), 1623-1635.

**A thermodynamic equation of state for pentafluoroethane (R-125).** / Sunaga, H.; Tillner-Roth, R.; Sato, H.; Watanabe, K.

Research output: Contribution to journal › Article

*International Journal of Thermophysics*, vol. 19, no. 2-6, pp. 1623-1635.

}

TY - JOUR

T1 - A thermodynamic equation of state for pentafluoroethane (R-125)

AU - Sunaga, H.

AU - Tillner-Roth, R.

AU - Sato, H.

AU - Watanabe, K.

PY - 1998/11

Y1 - 1998/11

N2 - We developed a fundamental equation of state for pentafluoroethane (R-125, CHF2CF3) which is represented in terms of a non-dimensional Helmholtz free energy. The equation has been established on the basis of selected measurements of the pressure-density-temperature relation, speed of sound, heat capacities, and saturation properties. Linear and non-linear regression analysis was employed to determine the functional form and the numerical parameters. The equation represents all the thermodynamic properties of R-125 in the liquid and gaseous phases for temperatures between the triple point and 470 K, and pressures up to 35 MPa. The uncertainties are estimated to be about ±0.05% or 0.1 kPa for the vapor pressure, ±0.05% for the liquid and vapor densities, about ±1% for the isobaric and isochoric heat capacities in the liquid, and ±0.5% or ±0.02% for the speed of sound in the liquid and vapor, respectively.

AB - We developed a fundamental equation of state for pentafluoroethane (R-125, CHF2CF3) which is represented in terms of a non-dimensional Helmholtz free energy. The equation has been established on the basis of selected measurements of the pressure-density-temperature relation, speed of sound, heat capacities, and saturation properties. Linear and non-linear regression analysis was employed to determine the functional form and the numerical parameters. The equation represents all the thermodynamic properties of R-125 in the liquid and gaseous phases for temperatures between the triple point and 470 K, and pressures up to 35 MPa. The uncertainties are estimated to be about ±0.05% or 0.1 kPa for the vapor pressure, ±0.05% for the liquid and vapor densities, about ±1% for the isobaric and isochoric heat capacities in the liquid, and ±0.5% or ±0.02% for the speed of sound in the liquid and vapor, respectively.

KW - Equation of state

KW - HFCs

KW - Pentafluoroethane

KW - R-125

KW - Refrigerant

KW - Thermodynamic properties

UR - http://www.scopus.com/inward/record.url?scp=0001953593&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0001953593&partnerID=8YFLogxK

M3 - Article

VL - 19

SP - 1623

EP - 1635

JO - International Journal of Thermophysics

JF - International Journal of Thermophysics

SN - 0195-928X

IS - 2-6

ER -