Semi-empirical modelling of a variable speed scroll compressor with vapour injection

•Semi empirical modelling of a variable speed scroll compressor with vapour injection.•Suction and injection flow rates, input power and discharge temperature are computed.•Model is tuned and validated against 63 experimental data.•89%–98% of calculated data are within ±5%, ±10% or ±5 K.

Vapour injection scroll compressors are nowadays gaining attention in vapour compression systems, especially in high temperature lift application, due to the advantages they provide. To date, proposed models of this kind of compressor are mainly deterministic models, requiring a detailed description of compressor geometry and allowing, in turn, minute calculation of the refrigerant state as function of orbiting angle. Semi-empirical models are largely proposed for standard scroll compressors in order to accurately compute compressor performance without the need of the knowledge of compressor geometrical feature. In this paper, a semi-empirical model of a variable speed scroll compressor with vapour injection is introduced and validated over a set of 63 experimental data finding that 89%–98% of calculated suction and injection refrigerant mass flow rates, compressor electrical power and refrigerant temperature at compressor discharge agree within ±5%, ±10% or ±5 K with respect to the experimental values.