Semi-empirical model of scroll compressors and its extension to describe vapor-injection compressors. Model description and experimental validation

This paper presents a semi-empirical model of scroll compressors and proposes a methodology in order to extend this model to vapor-injection scroll compressors. The model takes into account the ideal evolution of the refrigerant throughout the compressor and considers the main sources of losses in the compression process. The model is able to predict the compressor and volumetric efficiencies in terms of ten empirical parameters, which have a direct physical interpretation. For the model validation, a series of four non-injected scroll compressors of different capacities were tested using R-290 and a scroll compressor with vapor-injection (SCVI) was characterized using R-407C. Results show a correct agreement between the experimental and calculated compressor efficiencies, with a maximum deviation of ±5%. Furthermore, the model estimates accurately the discharge temperature of the refrigerant, compressor power input, and refrigerant mass flow rate in the suction and injection port. Finally, the SCVI model response was evaluated by varying the intermediate pressure and the injection superheat.