Thermal conductivity of alternative refrigerants in the liquid phase

Abstract

Measurements of the thermal conductivity of five alternative refrigerants, namely, difluoromethane (HFC-32), pentafluoroethane ( H FC-125 ), 1,1,1-trifluoroethane (HFC-143a), and dichloropentafluoropropanes (HCFC-225ca and HCFC-225cb), are carried out in the liquid phase. The range of temperature is 253-324 K for HFC-32, 257-305 K for HFC-125, 268-314 K for HFC-134a, 267-325 K for HCFC-225ca, and 286-345 K for HCFC-225cb. The pressure range is from saturation to 30 MPa. The reproducibility of the data is better than 0.5 %, and the accuracy of the data is estimated to be of the order of 1%. The experimental results for the thermal conductivity of each substance are correlated by an equation which is a function of temperature and pressure. A short discussion is given to the comparison of the present results with literature values for HFC-125. The saturated liquid thermal conductivity values of HFC-32, HFC-125, and HFC-143a are compared with those of chlorodifluoromethane (HCFC-22) and tetrafluoroethane (HFC-134a) and it is shown that the value of HFC-32 is highest, while that of HFC-125 is lowest, among these substances. The dependence of thermal conductivity on number of fluorine atoms among the refrigerants with the same number of carbon and hydrogen atoms is discussed.

Models for viscosity, thermal conductivity, and surface tension of selected pure fluids as implemented in REFPROP v10.0

“…The dilute-gas thermal conductivity data of Haynes (Haynes, 1994) from NIST were used to obtain the dilute-gas coefficients in Table 6 (located in the Appendix), and the wide-ranging fluid measurements of both Haynes (Haynes, 1994) and of Le Neindre et al (Le Neindre, Garrabos, & Kim, 2001) were used to obtain the residual coefficients in Table 6. The value of qd -1 in Table 4 was obtained by fitting, while the other coefficients in Table 4 are from the generalized model of Perkins et al (R. A. Perkins et al, 2013) Measurements of other researchers (Lee, Kim, & Ro, 2001;Tanaka, Nakata, & Makita, 1991;Yata, Hori, Kobayashi, & Minamiyama, 1996) and the data used in regression (Haynes, 1994;Le Neindre et al, 2001) are shown in the deviation plots in Figures 107 and 108. As seen in the deviation plots, there are still discrepancies in the data, and future work would be useful to determine the most reliable data sets.…”

Correlating Thermal-Conductivity Data for Ternary Liquid Mixtures

“…According to Yata et al [2], a linear relationship also holds for the thermal conductivity of refrigerants in the saturated liquid state, but Ro et al [3] correlated such data using a second-order polynomial:…”

“…For refrigerants, several investigators [2][3][4][5][6][7][8] represented the combined temperature and pressure dependence, of pure and specific binary and ternary refrigerant mixtures, by the following polynomial:…”

“…The two combining rule options for the binary cross parameters were compared. The adjustable parameters were determined using only the pure and binary (2,2) and Wassiljewa models also did well. The former performed best with mass fractions.…”

“…Such fluids include alkanes employed as heat carriers and thermal storage materials [1] and HFC refrigerants used in refrigeration and heat pump systems [2][3][4][5][6][7][8][9][10][11][12][13][14]. The thermal conductivity is a relevant transport property affecting heat transfer performance.…”