TY - JOUR
T1 - Local composition modelling of the thermodynamic properties of refrigerant and oil mixtures
AU - Martz, W. L.
AU - Burton, C. M.
AU - Jacobi, A. M.
N1 - measurement uncertainty. For both sets of data (from refs 6 and 8), measurement integrity is supported by a comparison of measured pure-refrigerant properties to reliable data from the literature. Example vapour pressure data from the study of Martz et al. 8 are provided in Figure 1 for the R22-POE mixture. Martz et al. discuss departures from ideal VLE behaviour in terms of fugacity and activity coefficients, and they find that departures from the Lewis-Randall rule are related to molecular size differences and intermolecular forces in the mixture. In all, the work by Grebner and Crawford 6 and Martz et al. 8 provides VLE data for the following refrigerant and oil combinations: R12-naphthenic, R12-paraffinic, R22-POE2, R134a-PAG, R134a-POE, R134a-POE2 and R125-POE2. These data will be used for comparing the six thermodynamic mixture models.
PY - 1996
Y1 - 1996
N2 - Six local composition models of the thermodynamic behaviour of mixtures are described. Using data from the literature and a non-linear regression analysis, a comparison of the predictive abilities of the models is undertaken for R12, R22, R134a and R125 with various oils. The Wilson and Heil equations provide the most consistent results, with the Heil equation providing a modest improvement over the Wilson model. Using a 95% confidence interval, the Heil equation predicted the behaviour of R12 with a paraffinic mineral oil to within 3.1%; its worst-case 2-σ error was 10.4% (R22 with a polyol ester oil), and its average 2-σ error for all of the mixtures was 6.2%. Using model parameters and error estimates from the regression analyses, pressure-temperature-concentration behaviour for these mixtures can be predicted for system design and simulation.
AB - Six local composition models of the thermodynamic behaviour of mixtures are described. Using data from the literature and a non-linear regression analysis, a comparison of the predictive abilities of the models is undertaken for R12, R22, R134a and R125 with various oils. The Wilson and Heil equations provide the most consistent results, with the Heil equation providing a modest improvement over the Wilson model. Using a 95% confidence interval, the Heil equation predicted the behaviour of R12 with a paraffinic mineral oil to within 3.1%; its worst-case 2-σ error was 10.4% (R22 with a polyol ester oil), and its average 2-σ error for all of the mixtures was 6.2%. Using model parameters and error estimates from the regression analyses, pressure-temperature-concentration behaviour for these mixtures can be predicted for system design and simulation.
KW - Refrigerant-oil mixtures
KW - Thermodynamic property modelling
UR - https://www.scopus.com/pages/publications/0029734560
UR - https://www.scopus.com/pages/publications/0029734560#tab=citedBy
U2 - 10.1016/0140-7007(95)00063-1
DO - 10.1016/0140-7007(95)00063-1
M3 - Article
AN - SCOPUS:0029734560
SN - 0140-7007
VL - 19
SP - 25
EP - 33
JO - International Journal of Refrigeration
JF - International Journal of Refrigeration
IS - 1
ER -