A thermodynamic model for an open regenerated inverse Brayton cycle with pressure drop irreversibilities is established using finite time thermodynamics considering the size constraints of real plant in Part 1 of this paper. The analytical formulae about the cooling load and coefficient of performance of refrigeration cycle, the heating load and coefficient of performance of heat pump cycle are derived, which indicate that the thermodynamic performance for open regenerated inverse Brayton cycle can be optimised by adjusting the mass flowrate. It is shown that the cooling load, heating load and the power input increase with the increase in the compressor inlet relative pressure drops, the coefficient of performance reaches its maximum at the optimal compressor ratio and the exhaust temperature is higher than that of the ambient, which is lower than that of the ambient only at small effectiveness of the regenerator.