Vapor pressure, density, and speed of sound of the R134a-R227ea refrigerants in the vapor phase

Abstract

The pressure on the dew line and density of the gas-phase 69.2 wt.% R134a / 30.8wt.% R227ea refrigerant were investigated using a constant volume piezometer in the temperature range from 293 to 373 K and at pressures from 0.45 to 3.1 MPa. The speed of sound of the 70.1 wt.% R134a / 29.9 wt.% R227ea mixture (323-373 K, 1.2-1.5 MPa) was also measured using an ultrasonic interferometer. The measurement errors of the temperature, pressure, density, and speed of sound were ±20 mK, ±4 kPa, ± (0.15–0.25)%, and ± (0.2–0.3)%, respectively. Approximation dependences of the studied properties were obtained and their errors were estimated. The obtained results were compared with the calculations using the REFPROP program.