BIBLIOS

Document type
Journal articles

Document subtype
Full paper

Title
Relative Permittivity and Dipole Moments of Replacement Refrigerant Mixtures (R408A and R409A) in the Liquid State

Participants in the publication
Ana P. C. Ribeiro (Author)
INSTITUTO SUPERIOR TÉCNICO
Carlos A. Nieto de Castro (Author)
Dep. Química e Bioquímica
CQE
Umesh V. Mardolcar (Author)
INSTITUTO SUPERIOR TÉCNICO

Summary
This paper provides reliable dielectric property information on two refrigerant mixtures regarded as replacements for chorodifluoromethane (CAS no. 75-45-6) (HCFC22) and R502 (CHClF2 + CClF2CF3) (w1 = 0.49; w2 = 0.51). Liquid phase relative permittivity measurements are reported for R408A (CHF2CF3 + CF3CH3 + CHClF2) (w1= 0.07; w2= 0.46; w3= 0.47) and R409A (CHClF2 + CHClFCH3 + CClF2CH3) (w1 = 0.60; w2 = 0.25; w3 = 0.15). The measurements were performed by using a direct capacitance method at temperatures from T = (233 to 303) K under pressures up to 16 MPa. A complete set of tables of experimental data, covering dielectric property needs for most engineering applications, is provided. The data obtained was correlated as a function of density, pressure, and temperature. The apparent dipole moments (μ∗) of R408A and R409A in the liquid state were obtained from the Kirkwood modification of the Onsager equation for the variation to the modified molar polarization with temperature and density. The μ∗ value found for R408A was 1.043·10−29 C·m and 1.047·10−29 C·m for R409A. The coefficient of thermal expansion and the coefficient of compressibility in the liquid state were derived from the experimental data, with uncertainties better than 2 % and 0.3 %, respectively.


Institution
FACULDADE DE CIÊNCIAS DA UNIVERSIDADE DE LISBOA

Where published
Journal of Chemical & Engineering Data

Publication Identifiers

Publisher
American Chemical Society (ACS)



Document Identifiers
DOI - https://doi.org/10.1021/je700433f
URL - http://dx.doi.org/10.1021/je700433f

Keywords
refrigerant mixtures R408A R409A relative permittivity Kirkwood equation isobaric thermal expansion isothermal compressibility

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