Summary

The performance of a compressor is affected by electrical, mechanical and thermodynamic inefficiencies. Electrical losses occur in the electric motor, while mechanical losses are due to friction in the bearings and oil pumping. Thermodynamic inefficiencies take place in the compression, expansion, suction and discharge processes and are associated with heat transfer, gas leakage, valve dynamics, among other aspects. The present thesis describes the development and validation of a numerical model for predicting the performance of rolling piston compressors commonly used in air conditioners. Relevant input data required by the model, such as clearances between moving parts, valve stiffness and natural frequency and electric motor efficiency, were obtained experimentally. Correlations for effective flow and force areas associated with the suction and discharge processes were derived from flow simulations, including the influence of the rolling piston. Experimental data for p-V diagram, as well as for compressor isentropic and volumetric efficiencies, were obtained in a calorimeter. Numerical predictions were compared with experimental data and showed good agreement in different operating conditions, represented by pairs of evaporating and condensing temperatures, validating the model developed.

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