Abstract: The invention relates to a refrigeration circuit having a mono- or multi-component refrigerant circulating therein, said refrigeration circuit comprising at least one expansion device. According to the invention, the expansion device is provided in the form of at least two valves (a, b, c, d) connected in parallel. Furthermore, the invention relates to a method of operating such a refrigeration circuit. Said method is characterized in that, in case of a defect of one of the valves (a, b, c, d) connected in parallel, said defective valve is taken out of operation and the or at least one of the additional valves ensures the control operation of the refrigeration circuit.

Abstract: Method for controlling an intermittently supercritically operating refrigeration circuit (2) for circulating a refrigerant in a predetermined flow direction having in flow direction a compressor (4), a heat-rejecting heat exchanger (10), a control valve (12) associated to the outlet (14) of the heat-rejecting heat exchanger (10) and a control (16) for controlling the control valve (12), wherein the method comprises the following steps: (a) in the subcritical mode, controlling the control valve (12) so that a predetermined “subcritical pressure” ensuring a predetermined sub-cooling of the liquid refrigerant at the outlet (14) of the heat-rejecting heat exchanger (10) is maintained; (b) in the supercritical mode, controlling the control valve (12) so that a predetermined “supercritical pressure”, which is optimized for optimum efficiency, of the supercritical refrigerant at the outlet (14) of the heat-rejecting heat exchanger (10) is maintained; and (c) in a border mode in a border region next to the critical p

Abstract: Refrigeration circuit (2) for circulating a refrigerant in a predetermined flow direction, having in flow direction a heat rejecting heat exchanger (4), an evaporator throttle valve (8), an evaporator (10), a compressor (22), an internal heat exchanger (16) placed with its “cool side” between the evaporator (10) and the compressor (22), an inlet temperature sensor (24) located between the evaporator (10) and the internal heat exchanger (16) and an outlet temperature sensor (26) located between the internal heat exchanger (16) and the compressor (22), and a control (28) for controlling the evaporator throttle valve (8) based on the inlet and outlet temperature sensor measurement, wherein the control is adapted for controlling the evaporator throttle valve (8) based on an inlet temperature setpoint at the inlet temperature sensor (24); and shifting the inlet temperature setpoint based on the outlet temperature sensor measurement (26).

Abstract: The invention relates to a refrigeration circuit having a mono- or multi-component refrigerant circulating therein, said refrigeration circuit comprising, in the direction of flow, a condenser, a collecting container, a relief device connected up-stream of an evaporator, an evaporator and a compressor unit with single-stage compression. According to the invention, there is an intermediate relief device (a) arranged between the condenser (1) and the collecting container (3). Furthermore, there is disclosed a method of operating a refrigeration device in which pressure relief of the refrigerant to an (intermediate) pressure of 5 to 40 bar is effected in the intermediate relief device (a) arranged between the condenser (1) and the collecting container (3).