5. Condensing pressure adjustment

The coefficient of performance of a refrigeration plant is all the better when, for the same evaporation temperature, the condensing pressure is itself lower, without being abnormally so. As mentioned above, in steady-state operation, mass flow is identical at the expansion valve, evaporator and compressor, and can be limited by any one of these three devices. This is the case when the compressor flow rate is greater than that of the fully open expansion valve. In fact, the mass flow rate $\dot{m}$ of an expansion valve orifice is :