Extracted, cooled, compressed/intercooled, cooling/ combustion air for a gas turbine engine

A system for cooling at least a first portion of a gas turbine engine having a high pressure compressor and a core gas stream, said cooling system comprising:

• a plurality of compressors disposed in serial flow relationship with one another and effective for compressing air, each of said compressors having an inlet and an outlet, wherein said inlet of a first, upstream one of said compressors receives air having a pressure which is less than or equal to a pressure of the core gas stream at an entrance to the high pressure compressor of the engine, said upstream compressor producing a first compressed airflow and wherein:
• each of said plurality of compressors comprises an auxiliary compressor driven by an auxiliary power source;
• and
• said auxiliary power source is coupled to each of said auxiliary compressors via at least one shaft;
• a first intercooler effective for reducing a temperature of said first compressed airflow, said first intercooler having a first inlet and a first outlet for said first compressed airflow receiving cooling from said first intercooler, said first inlet in fluid flow communication with said outlet of said upstream compressor and said first outlet in fluid flow communication with said inlet of a second one of said compressors, said first intercooler further including a second inlet and a second outlet for a first coolant fluid providing cooling to said first intercooler;
• wherein an airflow discharging from a last, downstream one of said compressors is used for cooling said at least a first portion of the engine.