A THERMAL MANAGEMENT SYSTEM FOR AN AIRCRAFT

A thermal management system for an aircraft comprises a first thermal bus, with 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 vapour compression system comprises, 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, with each of the compressor and the expansion valve being controlled by a controller. The first thermal bus comprises a first heat transfer fluid, and a first heat flow (Q) of waste heat energy generated by the first heat sources is transferred via the first heat transfer fluid to the heat sink. The vapour compression system comprises a refrigerant fluid, with a second heat flow (Q) of waste heat energy generated by the or each second heat source being transferred via the evaporator to the refrigerant. A third heat flow (Q) of heat energy in the refrigerant is transferred via the condenser to the first heat transfer fluid. The compressor is provided with a supplementary reservoir of refrigerant fluid, with the supplementary reservoir being configured to increase the volume of the refrigerant fluid in the vapour compression system during operation when a temperature of the first heat transfer fluid is equal to or less than a temperature of the or each second heat source.