The effect of the lubricating oil on heat transfer in a hermetic reciprocating compressor

In some types of hermetic refrigeration reciprocating compressors, the oil circulation pattern inside the crankcase produces an oil falling film on the inner wall of the compressor shell. The conjugate heat transfer between the shell and the oil affects the heat dissipation from the internal components to the external environment and, consequently, the compressor thermal profile. A differential model is proposed to calculate the oil film and compressor shell temperature distributions. This model is incorporated into an existing compressor model based on integral forms of the energy balances for its components. The combined (integrated) model results are verified against experimental data for the temperature of the components and of the compressor shell. The model can be used to predict the compressor performance as a function of the suction and discharge pressures, the total oil flow rate and the fraction of this flow rate flowing as a film on the shell.