Abstract: A vapour compression system (1) including a compressor unit (2) having at least one main compressor (3) and at least one receiver compressor (4), a heat rejecting heat exchanger (5), a receiver (7), an expansion device (8) and an evaporator (9) being arranged in a refrigerant path. The vapour compression system (1) further includes a bypass valve (12) fluidly interconnecting the gaseous outlet (10) of the receiver (7) and the main compressor(s) (3). A pressure difference across the bypass valve (12) is measured or derived, and a mass flow rate of refrigerant through the bypass valve (12) is derived, based at least on the pressure difference across the bypass valve (12), and using a fluid model. A minimum mass flow rate of refrigerant required to operate the receiver compressor (4) is derived, based on a minimum displacement volume of the receiver compressor (4) and using a fluid model taking prevailing operating conditions into account.

Abstract: The vapour compression system includes a compressor unit having at least one main compressor and at least one receiver compressor, a heat rejecting heat exchanger, a receiver, an expansion device and an evaporator being arranged in a refrigerant path. The vapour compression system further includes a bypass valve fluidly interconnecting the gaseous outlet of the receiver and the main compressor(s). An opening degree of the bypass valve is controlled to regulate the pressure prevailing in the receiver in accordance with a first pressure setpoint when a load demand of the vapour compression system exceeds a maximum capacity of the receiver compressor(s). The opening degree of the bypass valve is controlled to regulate the pressure prevailing in the receiver in accordance with a second pressure setpoint when the receiver compressor(s) is/are operating and the load demand of the vapour compression system is below the maximum capacity of the receiver compressor(s).

Abstract: A method for monitoring a refrigerant charge in a vapour compression system (1) is disclosed, the vapour compression system (1) including a compressor unit (2), a heat rejecting heat exchanger (3), a high pressure expansion device (4), a receiver (5), at least one expansion device (9, 10), and at least one evaporator (11, 12) arranged in a refrigerant path. A change in net mass flow into or out of the receiver (5) and/or a change in net enthalpy flow into or out of the receiver (5) is detected, and a pressure inside the receiver (5) is monitored as a function of time, following the detected change in net mass flow and/or in net enthalpy flow. A time constant being representative for dynamics of the receiver (5) is derived, based on the monitored pressure as a function of time, and information regarding a refrigerant charge in the vapour compression system (1) is derived, based on the derived time constant.

Abstract: A method for configuring a plurality of operating setpoints for a vapour compression system (1) is disclosed. The plurality of operating setpoints are divided into a first group (12) of operating setpoints to be generated manually and a second group (13) of operating setpoints to be generated automatically, and the operating setpoints are operated in accordance therewith. The manually generated operating setpoints (12) and the automatically generated operating setpoints (13) are provided to a setpoint manager (11), and the setpoint manager (11) checks if the provided operating setpoints (12, 13) are in compliance with a set of rules. In the case that at least some of the provided operating setpoints (12, 13) are not in compliance with the set of rules, the setpoint manager (11) adjusts at least some of the provided operating setpoints (12, 13) in accordance with the set of rules, thereby obtaining an adjusted set of operating setpoints.

Abstract: A vapour compression system (1) including a compressor unit (2) having at least one main compressor (3) and at least one receiver compressor (4), a heat rejecting heat exchanger (5), a receiver (7), an expansion device (8) and an evaporator (9) being arranged in a refrigerant path. The vapour compression system (1) further includes a bypass valve (12) fluidly interconnecting the gaseous outlet (10) of the receiver (7) and the main compressor(s) (3). A pressure difference across the bypass valve (12) is measured or derived, and a mass flow rate of refrigerant through the bypass valve (12) is derived, based at least on the pressure difference across the bypass valve (12), and using a fluid model. A minimum mass flow rate of refrigerant required to operate the receiver compressor (4) is derived, based on a minimum displacement volume of the receiver compressor (4) and using a fluid model taking prevailing operating conditions into account.

Abstract: The vapour compression system (1) includes a compressor unit (2) having at least one main compressor (3) and at least one receiver compressor (4), a heat rejecting heat exchanger (5), a receiver (7), an expansion device (8) and an evaporator (9) being arranged in a refrigerant path. The vapour compression system (1) further includes a bypass valve (12) fluidly interconnecting the gaseous outlet (10) of the receiver (7) and the main compressor(s) (3). A first pressure setpoint for a pressure prevailing in the receiver (7) and a second pressure setpoint for the pressure prevailing in the receiver (7) are defined, the second pressure setpoint being higher than the first pressure setpoint.

Abstract: A method for monitoring a refrigerant charge in a vapour compression system (1) is disclosed, the vapour compression system (1) including a compressor unit (2), a heat rejecting heat exchanger (3), a high pressure expansion device (4), a receiver (5), at least one expansion device (9, 10), and at least one evaporator (11, 12) arranged in a refrigerant path. A change in net mass flow into or out of the receiver (5) and/or a change in net enthalpy flow into or out of the receiver (5) is detected, and a pressure inside the receiver (5) is monitored as a function of time, following the detected change in net mass flow and/or in net enthalpy flow. A time constant being representative for dynamics of the receiver (5) is derived, based on the monitored pressure as a function of time, and information regarding a refrigerant charge in the vapour compression system (1) is derived, based on the derived time constant.

Abstract: A method for configuring a plurality of operating setpoints for a vapour compression system (1) is disclosed. The plurality of operating setpoints are divided into a first group (12) of operating setpoints to be generated manually and a second group (13) of operating setpoints to be generated automatically, and the operating setpoints are operated in accordance therewith. The manually generated operating setpoints (12) and the automatically generated operating setpoints (13) are provided to a setpoint manager (11), and the setpoint manager (11) checks if the provided operating setpoints (12, 13) are in compliance with a set of rules. In the case that at least some of the provided operating setpoints (12, 13) are not in compliance with the set of rules, the setpoint manager (11) adjusts at least some of the provided operating setpoints (12, 13) in accordance with the set of rules, thereby obtaining an adjusted set of operating setpoints.