Bubble pressure measurements for the (1,1,1,2-tetrafluoroethane+triethylene glycol dimethyl ether) system

Marchi, P.; Scalabrin, G.; Ihmels, E. Christian; Fischer, Kai; Gmehling, Jürgen

doi:10.1016/j.jct.2006.03.004

Cited by 11 publications

(15 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The graph in Figure 6 for bubble pressure proves that DEoS‐2 can reproduce this property with high accuracy over the whole composition range that is considered here. Anyway, Table 6 shows a limited inconsistency between the data of Marchi et al7 and the data of Coronas et al4 In fact, the second data set has a high bias value and appears as shifted with respect to the first one.…”

Section: Validationmentioning

confidence: 84%

“…The first one is valid for mole fractions of R134a greater than 0.94, that is approximately equivalent to a mass fraction greater than 0.90. For the present problem, two neurons in the hidden layer ( J = 2) were used and the regression of the resulting 14 parameters ( w ij and w ik ) was done using a limited number of data that were measured specifically for this work 7, 11. The chosen range is representative of the refrigeration plants operating conditions.…”

Section: Residual Contributionmentioning

confidence: 99%

“…Bubble pressure as a function of liquid mole fraction along some isotherms is shown in Figure 3. The lines were calculated from DEoS‐1; the experimental points from Marchi et al7 are also reported. The representation of the experimental data is very good, as is confirmed by the 0.15% AAD and by the other statistical data given in Table 5, showing also that this property is reproduced within the experimental error of the data.…”

Section: Validationmentioning

confidence: 99%

“…Polyalkylene glycols (PAGs) were proposed as suitable lubricants in combination with R134a. Several researchers have focused their attention on such mixtures: measurements of solubility data,2–7 of density data,8–11 and of viscosity data8, 12–14 were produced.…”

Section: Introductionmentioning

confidence: 99%

“…The obtained DEoS is a fundamental equation of state, because it is expressed in terms of Helmholtz energy, from which all of the thermodynamic properties can be directly calculated through simple mathematical derivations. The regression of the equation parameters is done using the available experimental data, part of which were specifically produced for the present modeling purpose 7, 11…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

A fundamental equation of state for the (R134a + triethylene glycol dimethyl ether) mixture

Marchi

Scalabrin

Ihmels³

et al. 2007

AIChE Journal

Self Cite

View full text Add to dashboard Cite

in Wiley InterScience (www.interscience.wiley.com).The thermodynamic properties of the mixture of 1,1,1,2-tetrafluoroethane (R134a) and triethylene glycol dimethyl ether (TriEGDME) have been modeled with equations of state in an extended corresponding states format. A recent equation of state for pure R134a was assumed as the reference while the scale factors have been obtained in neural network form by regression of experimental data for the mixture. The modeling was focused on the liquid phase, considering the possible application of such a mixture in a refrigeration plant; since the vapor pressure of pure TriEGDME is negligible over the considered temperature range, the vapor phase of the mixture at vapor-liquid equilibrium condition is almost pure R134a. Two fundamental equations are proposed herein. The first one, developed from a limited amount of experimental data is valid for R134a mole fractions greater than 0.94. The second equation was obtained from a wider data base; it has a larger number of free parameters to regress and covers the R134a mole fractions greater than 0.59. 2007 American Institute of Chemical Engineers AIChE J, 53: [1349][1350][1351][1352][1353][1354][1355][1356][1357][1358][1359][1360][1361] 2007 Keywords: extended corresponding states, neural networks, R134a, refrigerant þ lubricant mixtures, thermodynamic properties, TriEGDME IntroductionThe environmental problems connected with the use of chlorofluorocarbon (CFC) refrigerants, in particular the depletion of the stratospheric layer of ozone, have imposed the phase-out of such substances and their replacement with less harmful fluids. Consequently, the study of alternative refrigerants and of their properties has become a fundamental task for scientific and technical research.Nowadays, the fluids mainly used in the refrigeration and air-conditioning plants are hydrofluorocarbons (HFC) that show better environmental behavior, thanks to the absence of chlorine atoms in their molecules. Among the substances of this family, 1,1,1,2-tetrafluoroethane (R134a) is widely used, because of its favorable thermodynamic performances in compression cycles and its compatibility with the existing refrigeration plants designed for CFC refrigerants.The identification of a suitable alternative refrigerant does not completely solve the technical problem: in fact, in the compression plants, the working fluid is not a pure refrigerant (or a mixture of refrigerants), but a certain amount of lubricant, compatible and soluble with the refrigerant, must be added. Because the mineral oils that were used with CFCs for years show low solubility in HFC refrigerants, it is necessary to propose alternative lubricants. The problems posed by the selection of the lubricant have been widely studied in recent years; a partial review is given by Marsh and Kandil.1 Guidance for the choice of the most efficient lubricant for specific technical applications, as for instance the design of a refrigeration plant, requires the knowledge of the thermophysical properties of t...

show abstract

Section: Validationmentioning

confidence: 84%