Molecular properties of alternative refrigerants derived from dielectric-constant measurements

Journal Article · Sat Mar 01 04:00:00 EST 1997 · International Journal of Thermophysics

DOI:https://doi.org/10.1007/BF02575172· OSTI ID:675535

Barao, M T; Castro, C A.N. de ^[1]; Mardolcar, U V ^[2]

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1. Univ. de Lisboa (Portugal)
2. Inst. Superior Tecnico, Lisboa (Portugal). Dept. de Fisica

A review of the current work in Lisbon on the measurement of the dielectric constant of the liquid phase of some environmentally acceptable refrigerants proposed as alternative replacements of the chlorofluorocarbons (CFCs), responsible for the destruction of the ozone layer, is presented. Measurements on HCFC 141b, HCFC 142b, HCFC 123, HFC 134a, HFC 152a, and HFC 32 samples of stated purities of 99.8 mass % or better were performed as a function of pressure and temperature, in the temperature range from 200 to 300 K and at pressures up to 20 MPa. The ratio of the capacitances of a cell filled with the sample and under vacuum was measured with a direct capacitance method. The dielectric-constant measurements have a repeatability of 0.003% and an accuracy of 0.1%. The theory developed by Vedam et al. based on the Eulerian Strain and the Kirkwood equation for the variation of the modified molar polarization with temperature and density were applied to obtain the dipole moments of the refrigerants in the liquid state, to obtain a physical insight of the molecular behavior, and to understand the equilibrium configuration of these liquids.

• Sponsoring Organization: USDOE
• OSTI ID: 675535
• Report Number(s): CONF-9509483--
• Journal Information: International Journal of Thermophysics, Journal Name: International Journal of Thermophysics Journal Issue: 2 Vol. 18; ISSN 0195-928X; ISSN IJTHDY
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
DIELECTRIC PROPERTIES
DIPOLE MOMENTS
HALOGENATED ALIPHATIC HYDROCARBONS
LIQUIDS
MATERIAL SUBSTITUTION
PRESSURE DEPENDENCE
REFRIGERANTS
TEMPERATURE DEPENDENCE