Thermal management system for an aircraft

A thermal management system for an aircraft, the thermal management system comprising a first gas turbine engine, a first thermal bus, a first heat exchanger one or more first ancillary systems, a vapour compression system, one or more second ancillary systems and a second heat exchanger,

• wherein the first thermal bus comprises a first heat transfer fluid, the first heat transfer fluid being in fluid communication between the first gas turbine engine, the first heat exchanger, and the or each first ancillary system, such that a waste heat energy generated by at least one of the first gas turbine engine, and the or each first ancillary system, is transferred to the first heat transfer fluid,
• and wherein a waste heat energy generated by the or each second ancillary system is transferred to a second heat transfer fluid, the second heat exchanger is configured to transfer the waste heat energy from the second heat transfer fluid to the first heat transfer fluid, and the vapour compression system is configured to increase a temperature of the second heat transfer fluid having passed through the or each second ancillary system to a value greater than a temperature of the first heat transfer fluid entering the second heat exchanger, such that waste heat energy generated by the or each second ancillary system can be transferred to the first heat transfer fluid, and the first heat exchanger is configured to transfer the waste heat energy from the first heat transfer fluid to a dissipation medium,
• and wherein the waste heat energy transferred to the second heat transfer fluid is in a range of from 20 kW to 300 kW.