FUEL COOLED COOLING AIR

A gas turbine engine (100) includes a main compressor section (101) having a downstream most location (110), a cooling air tap (112) at a location upstream of the downstream most location (110), and a main turbine section (104, 106). The main turbine section (104, 106) and the main compressor section (101) are mounted within a housing, and each have rotatable components. A first heat exchanger (130) is connected to the cooling air tap (112) and to receive fuel to be supplied to a combustor (102), such that the fuel may cool the cooling air in the first heat exchanger (130). A boost compressor (128) is connected to receive air downstream of the first heat exchanger (130) and connected to deliver the cooling air to at least one of the rotatable components in at least one of the compressor and turbine sections (101, 104, 106).