Impact of refrigerant–oil solubility on an evaporator performances working with R-407C

High‐pressure viscosity and density of carbon dioxide + pentaerythritol ester mixtures: Measurements and modeling

“…This could affect, in an important manner, the heat transfer coefficients and the global performance of refrigeration system. 30,[59][60][61] In the (T,p) range analyzed in this work, the viscosity values of the pure lubricants are around two or three orders of magnitude higher than those of the studied mixtures. In the interval of composition considered in this work, the pressure dependence of the viscosity of the mixtures is close to that of the pure carbon dioxide, as can be observed in Figure 4.…”

The effect of oil in refrigeration: Current research issues and critical review of thermodynamic aspects

“…Because of oil presence, refrigerant/oil mixture becomes largely zeotropic, this equilibrium modification being described by the solubility curves. Youbi-Idrissi et al (2003a, 2004a) studied theoretically and experimentally the difference between the refrigeration capacity evaluated for an evaporator working with R-407C and a POE oil, with or without neglecting the presence of oil. This difference may reach 10% for a low evaporator outlet superheat but quickly decreases when increasing the superheat.…”

“…Youbi-Idrissi et al (2003a, 2004a proposed an alternative equation that highlights the effect of solubility:…”

“…In other words, the contribution of mixing heat of refrigerant-oil in the total enthalpy is less than 0.2% and can easily be neglected. From the above enthalpy calculation model, Youbi-Idrissi et al (2003a, 2004a plot Mollier-type diagrams for R-407C and two POE of the same viscosity grade (32 cSt at 40 C) but having a different solubility. Fig.…”

Influence of compressor oil admixtures on theoretical efficiency of a compressor system

“…Most of the indirect methods of determining the oil concentration in the different parts of refrigeration system are based on the information on RWF thermophysical properties (Andrade et al, 1999). To our knowledge, only a few papers are available in the literature which have considered caloric properties of the RWF and evaluated the effect of admixtures on the efficiency of the compressor system (Meltser, 1969;Hughes et al, 1982;Hewitt et al, 1996;Corr et al, 1996;Medvedev et al, 2004;Youbi-Idrissi et al, 2003Zhelezny, 2002;Zhelezny et al, 2004Zhelezny et al, , 2007aLottin et al, 2003), and the heat transfer (Zü rcher et al, 1998a,b;Kedzierski, 2001Kedzierski, , 2003. A very good review on this phenomenon has been recently published by Youbi-Idrissi and Bonjour (2008).…”