Refrigeration circuit (1b, 1c, 1d) circulating a refrigerant and comprising in the direction of flow of the refrigerant: at least one compressor; at least one condenser (14a, 14b); a refrigerant line; an expansion device inlet line; at least one expansion device; and at least one evaporator; wherein the refrigeration circuit (1b, 1c, 1d) further comprises: a heat rejecting heat exchanger for heat exchange of the refrigerant with a heating system, an input side of the heat rejecting heat exchanger being fluidly connected the output side of the compressor; a gas-liquid-separator fluidly connected to an output side of the heat rejecting heat exchanger and being configured to separate the refrigerant leaving the heat rejecting heat exchanger into a gaseous phase refrigerant portion and a liquid phase refrigerant portion, the gas-liquid-separator having a gaseous phase output line fluidly connected to an inlet side of the at least one condenser (14a, 14b) and a liquid phase output line which is fluidly connected to the expansion device inlet line and/or a collecting container provided upstream of the at least one expansion device inlet line; a liquid refrigerant control device arranged in the liquid phase output line, which is configured to control the flow of liquid refrigerant flowing out of the gas-liquid-separator; a liquid meter, which is configured to measure the level of liquid refrigerant collected within the gas-liquid-separator and to provide at least one signal indicative of the level of liquid refrigerant collected within the gas-liquid-separator; a liquid level control device coupled to the liquid meter and to the liquid refrigerant control device, the liquid level control device being configured to drive the liquid refrigerant control device based on the at least one signal provided by the liquid meter, characterized in that a pressure regulation valve is arranged in the gaseous phase output line; and wherein a collecting container is provided between the liquid phase output line and the expansion device inlet line. at least one compressor; at least one condenser (14a, 14b); a refrigerant line; an expansion device inlet line; at least one expansion device; and at least one evaporator; a heat rejecting heat exchanger for heat exchange of the refrigerant with a heating system, an input side of the heat rejecting heat exchanger being fluidly connected the output side of the compressor; a gas-liquid-separator fluidly connected to an output side of the heat rejecting heat exchanger and being configured to separate the refrigerant leaving the heat rejecting heat exchanger into a gaseous phase refrigerant portion and a liquid phase refrigerant portion, the gas-liquid-separator having a gaseous phase output line fluidly connected to an inlet side of the at least one condenser (14a, 14b) and a liquid phase output line which is fluidly connected to the expansion device inlet line and/or a collecting container provided upstream of the at least one expansion device inlet line; a liquid refrigerant control device arranged in the liquid phase output line, which is configured to control the flow of liquid refrigerant flowing out of the gas-liquid-separator; a liquid meter, which is configured to measure the level of liquid refrigerant collected within the gas-liquid-separator and to provide at least one signal indicative of the level of liquid refrigerant collected within the gas-liquid-separator; a liquid level control device coupled to the liquid meter and to the liquid refrigerant control device, the liquid level control device being configured to drive the liquid refrigerant control device based on the at least one signal provided by the liquid meter, characterized in that a pressure regulation valve is arranged in the gaseous phase output line; and wherein a collecting container is provided between the liquid phase output line and the expansion device inlet line.