Thermal management system for an aircraft

A method of operating a thermal management system for an aircraft, the thermal management system comprising a first thermal bus, the first thermal bus comprising, in a closed loop flow sequence, one or more first heat sources, a heat sink, a vapour compression system, and one or more second heat sources,

• the method comprising the steps of:
• providing a vapour compression system comprising, in closed loop flow sequence, a compressor, a condenser, a receiver, a first side of a recuperator, an expansion valve, an evaporator, a second side of the recuperator, and the compressor;
• providing the vapour compression system with a refrigerant fluid;
• providing a controller configured to control each of the compressor and the expansion valve;
• operating the expansion valve to a fully open condition;
• increasing a volume of refrigerant in the vapour compression system closed loop when a temperature of a first heat transfer fluid is equal to or less than a temperature of the or each second heat source;
• transferring a first heat flow (Q1) of waste heat energy generated by at least one of the first heat sources, to the first heat transfer fluid;
• transferring a second heat flow (Q2) of waste heat energy generated by the or each second heat source is transferred via the evaporator to the refrigerant
• transferring a third heat flow (Q3) of heat energy in the refrigerant generated by the or each second heat source is transferred via the condenser to the first heat transfer fluid;
• and
• transferring the waste heat energy from the first heat transfer fluid to a dissipation medium.