Die thermischen zustandsgrössen von 1,1-difluoräthylen

PvT Properties and Thermodynamic Property Correlations for the Low Global Warming Potential Hydrofluoroolefin Refrigerant R-1132a (1,1-Difluoroethene)

“…The newly determined critical temperature is around 0.1 % lower than the values provided previously in the literature by Otto and Thomas [ 12 ] and Low [ 5 ] and is 0.2 % lower than those by Mears et al [ 11 ]. The experimental uncertainty of the temperature measurement at the critical point of the present work is 0.01 K; Mears et al’s uncertainty is 0.5 K, Low’s [ 5 ] uncertainty was stated to be 0.3 K, while Otto and Thomas [ 12 ] optimized the critical parameter using a correlation for the saturation pressures. Therefore, the new measurement can be considered as an improved direct measurement of the critical temperature due to the smaller uncertainty and also since the values are within the uncertainty range of Low’s measurements.…”

“…This signifies the reproducibility of the measurement using a different apparatus as well as the accuracy of the critical temperature and density. The R-1132a critical pressures previously provided in the literature by Mears et al [ 11 ], Low [ 5 ] as well as Otto and Thomas [ 12 ] show around 0.3 % deviations from the current value, while the Ambrose method has much higher deviations reaching 5 %. Due to the lower temperature uncertainties as well as the similar values of the critical density value, the newly determined critical pressure within this work can be considered as an improved and updated direct measurement.…”

“…Two-phase experimental vapor pressure data from the literature by Otto and Thomas [ 12 ], Tomassetti and di Nicola [ 15 ] and Thu et al [ 17 ] and also vapor pressure data determined using the EoS developed by Low [ 5 ] were obtained for comparison. Though Tomassetti and di Nicola’s data are the newest, it does not include a new measurement of the critical point and was limited to the range between 220 K and 280 K. The present measurements overlap Tomassetti and di Nicola’s range starting from 240 K to 280 K and additionally provide higher temperature vapor pressures up to the critical pressure, overlapping those provided by Otto and Thomas and Low.…”

“…2 Vapor pressure deviations in the two-phase region along the saturation pressure curve in comparison to the optimized correlation of Eq. 6 : App-WRT; App-HRT; App-LRT; Otto and Thomas [ 12 ]; Low [ 5 ]; Tomassetti and di Nicola [ 15 ]; and Thu et al [ 17 ] …”

“…As for the thermodynamic properties of R-1132a, Mears et al [ 11 ] presented several thermodynamic properties of pure R-1132a in 1955, where several techniques were used to measure the PvT properties in the vapor and liquid phases, vapor pressures, saturated liquid and vapor densities, critical parameters and liquid viscosities. Otto and Thomas [ 12 ] in 1964, presented the PvT properties mostly in the subcooled and supercritical regions, the vapor pressures, the saturated densities and the critical parameters. Koschine and Lehmann [ 13 ] measured the second and third virial coefficients for three isotherms in 1992, and Dymond et al [ 14 ] presented the second virial coefficients and correlations in 2002.…”