PROCÉDÉ POUR COMMANDER LE FONCTIONNEMENT D'UN SYSTÈME DE COMPRESSION DE VAPEUR DANS UN MODE SOUS-CRITIQUE ET DANS UN MODE SUPERCRITIQUE

摘要

A method for controlling operation of a vapor compression system (1), and a vapor compression system (1) are disclosed. The vapor compression system (1) comprises a compressor (2), a heat rejecting heat exchanger (3), a controllable valve (4), a receiver (5), at least one expansion device and at least one evaporator arranged along a refrigerant path having refrigerant flowing therein. The vapor compression system (1) is capable of being operated in a subcritical control regime as well as in a supercritical control regime. The method comprises the steps of measuring a temperature, TGC, of refrigerant leaving the heat rejecting heat exchanger; calculating a pressure reference, PGC, Ref, based on the measured temperature, TGC, and using a calculation formula being applicable to the subcritical control regime as well as to the supercritical control regime; and controlling an opening degree of the controllable valve in order to obtain a pressure of refrigerant leaving the heat rejecting heat exchanger which is equal to the calculated pressure reference, PGC, Ref. Since the calculation formula is applicable to the subcritical control regime as well as to the supercritical control regime, only one calculation formula is necessary, and the vapor compression system (1) can thereby be controlled in a very easy manner.