System and method for refrigerant management in an electric vehicle

A refrigerant management system in a heat flux management system for an electric vehicle, the refrigerant management system comprising a vehicle air conditioning circuit comprising a heat pump circuit with a heating function and a refrigeration cycle refrigerant circuit, the air conditioning circuit comprising a heat pump condenser in thermal communication with a heat source, a refrigerant evaporator in thermal communication with the heat source, an evaporator associated with an expansion valve, and a refrigerant compressor, wherein the components are fluidly connected to one another by a refrigerant line, an accumulator fluidly coupled in the refrigerant line downstream of the heat pump condenser, the refrigerant evaporator and evaporator and upstream of the refrigerant compressor,

• the heat pump circuit comprising an indirect condenser downstream of the refrigerant compressor and in thermal communication with a heat sink and the refrigerant evaporator and the evaporator in fluid communication with the refrigerant compressor and the indirect condenser;
• the refrigeration cycle refrigerant circuit comprising the heat pump condenser in fluid communication with the compressor;
• wherein the air conditioning circuit is switchable between a heating mode in which the heat pump circuit is in fluid communication with the compressor and the heat pump condenser is isolated from fluid communication with the compressor and a cooling mode wherein the refrigerant circuit is in fluid communication with the compressor by actuation of at least one valve;
• wherein the air conditioning circuit comprises a sensor at the compressor inlet operable to monitor refrigerant temperature and pressure;
• and
• wherein when the system is in the heating mode, a shut off valve in line between the heat pump condenser and the accumulator is operable to open to initiate a cold start mode in which a temporary fluid communication is provided between the heat pump condenser and the accumulator in the heat pump circuit when:
• the sensor detects one or both of:
• a superheated refrigerant at the compressor inlet and a temperature gradient of more than 3 Kelvin between the ambient temperature and the temperature at the compressor inlet.