Flexible turbine arrangement air cycle machine with adaptive heat exchanger

A method of controlling flow in an environmental control system comprising:

• directing a first portion of an engine bleed fluid through a first passage of a primary heat exchanger, wherein the primary heat exchanger also comprises a second passage, and a third passage;
• directing a second portion of the engine bleed fluid through a first valve in an open position and into the second and third passage of the primary heat exchanger, wherein the second portion is divided between the second passage and the third passage;
• directing the second portion of the engine bleed fluid in the third passage to an outlet of the primary heat exchanger;
• directing the engine bleed fluid at the outlet of the primary heat exchanger to an inlet of a compressor;
• directing both the first portion of the engine bleed fluid from the first passage and the second portion of the engine bleed fluid in the second passage to a second valve via a bypass line when the second valve is in an opened position;
• directing the engine bleed fluid from the second valve to the inlet of the compressor;
• compressing the engine bleed fluid via the compressor into a compressor exhaust fluid, wherein the compressor is mechanically coupled to a first turbine and a second turbine via a shaft;
• directing the compressor exhaust fluid through an outlet of the compressor and through a secondary heat exchanger;
• directing a first portion of the compressor exhaust fluid into the first turbine and through a second load cooling heat exchanger;
• directing an exhaust fluid of the first turbine through a first load cooling heat exchanger, then through a fourth valve in an open position, and then to a system outlet;
• directing a second portion of the compressor exhaust fluid through a third valve and into the second turbine when the third valve is in an open position;
• and
• directing an exhaust fluid of the second turbine through a second load cooling heat exchanger and then to the system outlet.