Isochoric Heat Capacity Measurements for Binary Refrigerant Mixtures Containing Difluoromethane (R32), Pentafluoroethane (R125), 1,1,1,2-Tetrafluoroethane (R134a), and Trifluoroethane (R143a) From 200 to 345 K at Pressures ato 35 Mpa

Published

June 1, 1999

Author(s)

Joe W. Magee

Abstract

Molar heat capacities at constant volume C_v were measured for binary refrigerant mixtures with an adiabatic colorimeter with gravimetric determinations of the amount of substance. Temperatures ranged from 200 to 345 K, while pressures extended up to 35 Mpa. Measurements were conducted on liquid samples with equimolar compositions for the following binary systems: R32/R134a, R32/R125, R125/R134a, and R125/R143a. The uncertainty is 0.002 K for the temperature rise and is 0.2% for the change-of-volume work, which is the principal source of uncertainty. The expanded relative uncertainty (with a coverage factor k=2 and thus a two-standard deviation estimate) for C_v is estimated to be 0.7%.

Citation

International Journal of Thermophysics

Volume

21

Issue

No. 1

Pub Type

Journals

Keywords

1, 1, 1, 2-tetrafluoroethane, binary mixtures, difluoromethane, heat capacity, pentafluoroethane, R125, R134a, R143a, R32

Citation

Magee, J. (1999), Isochoric Heat Capacity Measurements for Binary Refrigerant Mixtures Containing Difluoromethane (R32), Pentafluoroethane (R125), 1,1,1,2-Tetrafluoroethane (R134a), and Trifluoroethane (R143a) From 200 to 345 K at Pressures ato 35 Mpa, International Journal of Thermophysics (Accessed October 2, 2025)