A general methodology for energy comparison of intermediate configurations in two-stage vapour compression refrigeration systems

► A new methodology for the general energy evaluation of inter-stage configurations in two-stage vapour compression systems is set out. ► This methodology allows comparing any intermediate configuration by means of two characteristic parameters, the subcooling and desuperheating parameters. ► Seven intermediate configurations (the most known) are analysed and compared for refrigerants R-717 and R-404A. ► We can conclude that subcooling is always positive for COP, but the desuperheating influence on COP will depend strongly on the refrigerant behaviour.