Virial Coefficients from Burnett Measurements for the R23 + N2O System

Abstract

This paper presents experimental results for the trifluoromethane (R23) + nitrous oxide (N 2 O) system, which has been chosen as a working fluid for low-temperature applications since it might be a valid option for the lowtemperature stage in a cascade cycle. The thermodynamic properties of the binary mixture's constituents are well known from the literature, but no experimental results have been published to date on the PVTx properties of this binary system. PVTx measurements were obtained for the binary R23 + N 2 O system for three isotherms (303, 323, and 343 K), performing 15 Burnett expansions in a range of pressures from about 4400 to 80 kPa. The second and third virial coefficients were derived from experimental results together with the second and third cross virial coefficients. The experimental uncertainties in the second and third virial coefficients were estimated to be within ±1 cm 3 ·mol −1 and ±500 cm 6 ·mol −2 , respectively.