Hermetic refrigerating compressors and CFC substitution

Abstract

This paper presents a basic criterion for determining the most feasible substitute refrigerants for CFC 12 in small refrigerating hermetic compressors. The method includes a simple analysis of some physical and thermodynamic properties of each refrigerant within the ranges of evaporating and condensing temperatures in which small refrigerating systems work. Parameters such as vapour pressure, compression ratio, final isentropic compression temperature and volumic refrigerant effect allow a relative comparison between the refrigerants. The Embraco procedure for the development of hermetic compressors adjusted to new refrigerants is also described. Project optimization, material compatibility analysis, performance and reliability product tests and means of production are considered. A time frame is established for the procedure, from the preliminary refrigerant analysis through to the start up of production. The strategy of the phase in of new environmental friendly refrigerants versus the phase out of CFC compounds is discussed. Focus is given to the differences between developed and developing countries, with Brazil used as an example.