Specific Heat Capacity at Constant Volume for R125 and R410a at Temperatures from (300 to 400) K and Pressures to 20 MPa

Published

August 6, 2005

Author(s)

Richard A. Perkins, Joe W. Magee

Abstract

Specific heat capacities at constant volume (Cv) were measured with an adiabatic calorimeter for pure pentafluoroethane (R125) and an azeotrope-like mixture of R32 and R125 (R410A) with a mole fraction composition of 0.6975 difluoromethane + 0.3025 pentafluoroethane. Temperatures ranged from 300 K to 400 K, and pressures ranged from 3 MPa to 20 MPa. Measurements were conducted on single-phase liquid and compressed gaseous samples along isochores. Density was reported during each calorimetric experiment. The R410A mixture was gravimetrically prepared from high-purity substances. The principal sources of uncertainty are the temperature-rise measurement and the change-of-volume work adjustment. The expanded relative uncertainty (with a coverage factor k=2 and thus a 2-standard-deviation estimate) for Cv is estimated to be 2 % for liquid-phase results, increasing to 4 % for gas results (below critical density). The expanded relative uncertainty for density is 0.2 %.

Citation

Journal of Chemical and Engineering Data

Volume

50

Pub Type

Journals

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Keywords

density, isochoric specific heat, pentafluoroethane, R125, R410A

Citation

Perkins, R. and Magee, J. (2005), Specific Heat Capacity at Constant Volume for R125 and R410a at Temperatures from (300 to 400) K and Pressures to 20 MPa, Journal of Chemical and Engineering Data, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=30036 (Accessed January 15, 2025)