Scroll compressor, suction superheating, NTU method
Suction superheating plays a major role in determining the efficiency degradation of hermetic scroll compressors. Current models to predict superheating are usually experimentally calibrated and therefore can only be applied to existing compressors. This paper presents a thermal model to estimate suction superheating in scroll compressors, based on the NTU method for heat exchangers design. The model considers an isothermal surface exchanging heat with the gas in the suction path and in the discharge plenum. Compared to other models, the new approach described herein has the advantage of not requiring any experimental input data. The thermal model is coupled to a thermodynamic model and applied to evaluate the performance of a scroll compressor. The model was capable to predict the suction gas temperature in good agreement with experimental data, making it particularly useful for compressor design.