Refrigeration apparatus controlling opening degree of a second expansion mechanism based on air temperature at the evaporator or refergerant temperature at the outlet of a two stage compression element

Abstract

A refrigerating apparatus, where refrigerant reaches a supercritical state in at least part of a refrigeration cycle, includes at least one expansion mechanism, an evaporator connected to the expansion mechanism, first and second sequential compression elements, a radiator connected to the discharge side of the second compression element, a first refrigerant pipe interconnecting the radiator and the expansion mechanism, a heat exchanger arranged to cause heat exchange between the first refrigerant pipe and another refrigerant pipe. Preferably, a heat exchanger switching mechanism is switchable so that refrigerant flows in the first refrigerant pipe through the first heat exchanger or in a heat exchange bypass pipe connected to the first refrigerant pipe. Alternatively, a heat exchanger switching mechanism increases refrigerant flowing through a second expansion mechanism when an air temperature at the evaporator and/or a compressed refrigerant temperature detected is higher and/or lower than predetermined values.