A subsystem for a vapour-compression system having a compressor and a condenser, the subsystem including: a storage assembly comprising: a container with an internal chamber for storing refrigerant, a first storage port and a second storage port, the second storage port is fluidly communicable with a compressor inlet of the compressor for flow of refrigerant, the storage assembly being configured to receive and store refrigerant in a storing configuration, and release refrigerant stored therein to the compressor inlet of the compressor in a releasing configuration; a flow-directing assembly in fluid communication with the storage assembly configured for flow of refrigerant, and fluidly communicable with a condenser inlet of the condenser and a compressor outlet of the compressor for flow of refrigerant, the flow-directing assembly being configured to direct refrigerant from the compressor outlet to the storage assembly in a first flow configuration, and direct refrigerant from the compressor outlet to the condenser inlet in a second flow configuration, characterized in that the flow-directing assembly includes a first flow port, a second flow port, a third flow port, a first flow valve, a second flow valve, a third flow valve, a first sensor located near the first flow port to measure the temperature and pressure of refrigerant at the first flow port and a second sensor located near the second flow port to measure the temperature and pressure of refrigerant at the second flow port, wherein the first flow port is fluidly connected to the second flow port, the third flow port and fluidly connectable to the compressor outlet, the second flow port is fluidly connected to the third flow port and fluidly connectable to a reversing inlet and the third flow port is fluidly connected to the first storage port of the storage assembly, the first flow valve is located in the connection between the first flow port and the second flow port, the second flow valve is located in the connection between the first flow port and the third flow port, and the third flow valve is located in the connection between the second flow port and the third flow port,. a storage assembly comprising: a container with an internal chamber for storing refrigerant, a first storage port and a second storage port, the second storage port is fluidly communicable with a compressor inlet of the compressor for flow of refrigerant, the storage assembly being configured to receive and store refrigerant in a storing configuration, and release refrigerant stored therein to the compressor inlet of the compressor in a releasing configuration; a flow-directing assembly in fluid communication with the storage assembly configured for flow of refrigerant, and fluidly communicable with a condenser inlet of the condenser and a compressor outlet of the compressor for flow of refrigerant, the flow-directing assembly being configured to direct refrigerant from the compressor outlet to the storage assembly in a first flow configuration, and direct refrigerant from the compressor outlet to the condenser inlet in a second flow configuration, characterized in that the flow-directing assembly includes a first flow port, a second flow port, a third flow port, a first flow valve, a second flow valve, a third flow valve, a first sensor located near the first flow port to measure the temperature and pressure of refrigerant at the first flow port and a second sensor located near the second flow port to measure the temperature and pressure of refrigerant at the second flow port, wherein the first flow port is fluidly connected to the second flow port, the third flow port and fluidly connectable to the compressor outlet, the second flow port is fluidly connected to the third flow port and fluidly connectable to a reversing inlet and the third flow port is fluidly connected to the first storage port of the storage assembly, the first flow valve is located in the connection between the first flow port and the second flow port, the second flow valve is located in the connection between the first flow port and the third flow port, and the third flow valve is located in the connection between the second flow port and the third flow port,.