Multiple mode environmental control system for pressurized aircraft cabin

A multiple-mode auxiliary power unit based environmental control system for a pressurizable aircraft cabin having a cabin air inlet and a cabin air outlet, comprising:

• a ram air inlet;
• an environmental control system exhaust outlet;
• a cabin air cooling system including an inlet and an outlet,
• said environmental control system exhaust outlet being connected to said cabin air inlet;
• a turbomachine including a compressor connected between said ram air inlet and said cooling system inlet, and a combustion turbine and a power recovery turbine mechanically coupled to said compressor, said turbines being connected between said environmental control system exhaust outlet and said cabin air outlet;
• a motor generator coupled to said compressor and said turbines;
• and
• a heat exchanger having first and second flow paths in heat exchange relation with each other, said first flow path serving to interconnect said compressor and said cooling system flow path and said second flow path serving to interconnect said cabin air outlet and said turbines.

A multiple-mode auxiliary power unit based environmental control system for a pressurizable aircraft cabin having a cabin air inlet and a cabin air outlet, comprising:

• a ram air inlet;
• an environmental control system exhaust outlet;
• a cabin air cooling system including an inlet and an outlet;
• said environmental control system exhaust outlet being connected to said cabin air inlet;
• a turbomachine including a compressor connected between said ram air inlet and said cooling system inlet, and one or more turbines mechanically coupled to said compressor, said one or more turbines being connected between said environmental control system exhaust outlet and said cabin air outlet;
• a motor coupled to said compressor and said one or more turbines;
• and
• a combustor connected to one or more of the turbines.

A multiple-mode auxiliary power unit based environmental control system for a pressurizable aircraft cabin having a cabin air inlet and a cabin air outlet, comprising:

• a ram air inlet;
• an environmental control system exhaust outlet;
• a cabin air cooling system including an inlet and an outlet;
• said environmental control system exhaust outlet being connected to said cabin air inlet;
• a turbomachine including a compressor connected between said ram air inlet and said cooling system inlet, and turbines mechanically coupled to said compressor, said turbines being connected between said environmental control system exhaust outlet and said cabin air outlet;
• a motor coupled to said compressor and said turbines;
• and
• a heat exchanger having first and second flow paths in heat exchange relation with each other, said first flow path serving to interconnect said compressor and said cooling system flow path and said second flow path serving to interconnect said cabin air outlet and said turbines.

A multiple-mode auxiliary power based environmental control system for a pressurizable aircraft cabin having a cabin air inlet and a cabin air outlet, comprising:

• a ram air inlet;
• an environmental control system exhaust outlet;
• a cabin air cooling system including an inlet and an outlet;
• said environmental control system exhaust outlet being connected to said cabin air inlet;
• one or more turbomachines, each including a compressor connected between said ram air inlet and said cooling system inlet, and a combustion turbine and a power recovery turbine mechanically coupled to said compressor, said turbines being connected between said environmental control system exhaust outlet and said cabin air outlet;
• one or more motor generators, each coupled to said compressor and said turbines;
• one or more heat exchangers, each having first and second flow paths in heat exchange relation with each other, said first flow path serving to interconnect said compressor and said cooling system flow path and said second flow path serving to interconnect said cabin air outlet and said turbines;
• and
• at least one said turbomachine having a selectively-operable duct interconnecting said compressor and said combustion turbine, and bypassing said heat exchanger, and a second selectively-operable ducting system that can interconnect said heat exchanger and said power recovery turbine or alternatively interconnect one or more of said heat exchangers with a corresponding one of said combustion turbines or alternatively halt flow from said heat exchanger to any of said turbines.