An Analytical Model of Heat Transfer to the Suction Gas in a Low-Side Hermetic Refrigeration Compressor

H. Doyle Thompson Dept. of Mechanical Engineering Purdue University W. Lafayette, IN 47907 .(317) 494-5624 Heat transfer to the suction gas in a hermetic compressor is known to have adverse effects on compressor performance. This can be explained in an overall sense by thermodynamic cycle analysis. The extent of suction gas heated. inside the compressor and the areas in which this heating occurs requires a more detailed. heat transfer analysis. The analytical model for this stud.y is a small (about 1/3 horsepower), low-side, reciprocating, hermetic compressor. The heat transfer equations for this model are, d.erived from stead.y-state energy balances on the overall system and on various compressor components. Where applicable, heat transfer coefficients are d.etermined from correlations found in the literature. A volumetric efficiency and a compression efficiency are determined from the experimental data. Some of the heat transfer coefficients for the complex threedimensional geometries were also d.etermined from experimental measurements. The model is used to predict the compressor performance over a range of operating conditions. Comparison with experimental measurements shows that the major trends are predicted by the model. Model adequacy and potential improvements are d.iscussed.