Effect of temperature on the dielectric properties of hydrofluoroethers and fluorinated ketone

Dielectric Properties of Refrigerant Fluids HFO-1336mzz-E, HFC-245fa, and HFE-7100

“…Both liquids show very good dielectric strength compared to the one of HFE-7100 reported in [16]. Even if obtained with a different technique, the AC values in [16] at room temperature may be put in comparison to the DC values reported in this paper.…”

“…where Cx is the capacitance of the vessel filled with the substance with unknown real permittivity 𝜀 𝑥 ′ , Ca is the vessel (b) Figure 7. Real permittivity of liquid HFO-1336mzz(E) (a) and HFC-245fa (b) obtained with dielectric spectroscopy similarly to what done in [16] and verified using the test vessel of Figure 2 and AC voltage application. The dielectric spectroscopy measurements have been obtained using reference liquid Novec 649 and equation (3) with and 𝜀 𝑛 ′ =1.8 (dashed lines, lower uncertainty bound) or 1.9 (continuous lines, upper uncertainty bound).…”

“…For what concerns HFE-7100, values ranging between 1-4•10 -8 S/m are reported in [16] at ambient temperature and under 250 V/mm field, therefore in similar range as HFC-245fa.…”

“…We report here for the first time the real permittivity and the dissipation factor of HFO-1336mzz(E) and HFC-245fa, obtained with AC spectroscopy using a 1260A impedance/gain-phase analyzer and a Solartron 1296 dielectric interface, similarly to what done in [16]. Further verification tests were also performed with the setup shown Figure 2, by applying high voltage (up to 20 kV) AC signal at frequency f from a voltage transformer and measuring the current with a Keithley 2002 Multimeter.…”

“…Paper [16] reports several measurement, including ageing effect, and an AC 50% BD probability of 97.4 kV/cm at 295 K In conclusion, in the liquid phase, the dielectric strength of HFO-1336mzz(E) is higher than both HFC-245fa and HFE-7100, the latter having the worse performance, approximately half the HFO-1336mzz(E) one.…”