Analysis of the Journal Bearing Performance in a CO2 Reciprocating Compressor

CFCs, HCFCs are stipulated to phase out, and other alternative refrigerants like R134a, are also constrained as a result from their high GWP values. CO2 as a natural working fluid now is used in reciprocating compressors due to its uniquely beneficial properties (ozone depletion potential, ODP=0; global warming potential, GWP =1). However, one remarkable characteristics of the CO2 reciprocating compressor operated in trans-critical region is the high operating pressure, which may impose high pressure loads on the connecting–rod big end bearing, further on the crankshaft journal bearings through the slider-crank mechanism. The work presented here is trying to study the friction losses of crankshaft journal bearings in a CO2 reciprocating compressor, by using a multiple regression method developed by Stachowiak and Batchelor(2001). The bearing performances depend mostly on the oil viscosity. In this case, the solubility of the CO2 into the lubricating oil is taken into consideration, which affects the oil viscosity.