## 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 |
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Pages (from-to) | 1623-1635 |

Number of pages | 13 |

Journal | International Journal of Thermophysics |

Volume | 19 |

Issue number | 6 |

DOIs | |

Publication status | Published - 1998 Nov |

## Keywords

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

## ASJC Scopus subject areas

- Condensed Matter Physics