Refrigeration circuit configured for circulating a refrigerant and comprising in the direction of flow of the refrigerant: at least one compressor (2a, 2b, 2c, 2d); at least one heat recovery heat exchanger; a gas/liquid separator; at least one gas cooler/condenser; at least one high-pressure expansion device; a receiver; and at least one evaporator with at least one evaporator associated expansion device fluidly connected upstream thereof; wherein the gas/liquid separator comprises: a refrigerant inlet line fluidly connected to an outlet-side of the at least one heat recovery heat exchanger; a gaseous phase outlet line fluidly connected to an inlet side of the at least one gas cooler/condenser; and a liquid phase outlet line fluidly connected to the receiver; wherein the refrigeration circuit further comprises: at least one switchable valve, which is switchable between a closed state and at least two different open states and configured for selectively opening and closing the liquid phase outlet line of the gas/liquid separator and a control unit, characterized by a liquid level sensor, which is configured for sensing the level of liquid refrigerant collected at the bottom of the gas/liquid separator; and by the control unit being configured for controlling the at least one switchable valve based on the level of liquid refrigerant detected by the liquid level sensor. at least one compressor (2a, 2b, 2c, 2d); at least one heat recovery heat exchanger; a gas/liquid separator; at least one gas cooler/condenser; at least one high-pressure expansion device; a receiver; and at least one evaporator with at least one evaporator associated expansion device fluidly connected upstream thereof; wherein the gas/liquid separator comprises: a refrigerant inlet line fluidly connected to an outlet-side of the at least one heat recovery heat exchanger; a gaseous phase outlet line fluidly connected to an inlet side of the at least one gas cooler/condenser; and a liquid phase outlet line fluidly connected to the receiver; a refrigerant inlet line fluidly connected to an outlet-side of the at least one heat recovery heat exchanger; a gaseous phase outlet line fluidly connected to an inlet side of the at least one gas cooler/condenser; and a liquid phase outlet line fluidly connected to the receiver; wherein the refrigeration circuit further comprises: at least one switchable valve, which is switchable between a closed state and at least two different open states and configured for selectively opening and closing the liquid phase outlet line of the gas/liquid separator and a control unit, characterized by a liquid level sensor, which is configured for sensing the level of liquid refrigerant collected at the bottom of the gas/liquid separator; and by the control unit being configured for controlling the at least one switchable valve based on the level of liquid refrigerant detected by the liquid level sensor. at least one switchable valve, which is switchable between a closed state and at least two different open states and configured for selectively opening and closing the liquid phase outlet line of the gas/liquid separator and a control unit, characterized by a liquid level sensor, which is configured for sensing the level of liquid refrigerant collected at the bottom of the gas/liquid separator; and by the control unit being configured for controlling the at least one switchable valve based on the level of liquid refrigerant detected by the liquid level sensor.