A system includes a fuel cell stack. A heat exchanger has an air passage in thermal communication with an H.sub.2O passage for heat exchange between air and H.sub.2O. An exhaust outlet of the fuel cell stack is connected in fluid communication with an H.sub.2O inlet of the heat exchanger for supplying H.sub.2O to the heat exchanger.

An autonomous air conditioning system for an aircraft includes a compressor compressing ambient air and supplying compressed air, a first portion of the compressed air being injected into a cabin of the aircraft so as to condition the cabin air in terms of pressure and of temperature. The autonomous system further includes an electric motor providing mechanical energy to the compressor. The system includes a fuel cells stack supplied with air by a second portion of the compressed air supplied by the compressor and supplying electrical energy, the electric motor being electrically powered with electrical energy supplied by the fuel cells stack. Thus, the cabin air conditioning is performed autonomously, avoiding the need to modify a pre-existing electrical network of the aircraft.

An aircraft fuel tank inerting system includes an inlet, an oxygen absorption unit, and a vent to discharge oxygen from the system. The inlet may be configured to be in fluid communication with a ullage of a fuel tank. In embodiments, the oxygen absorption unit is in communication with the inlet and includes a chamber, a temperature reversible oxygen absorption medium within said chamber, and a temperature controller for selectively heating or cooling the medium. The reversible oxygen absorption medium may be a medium which absorbs oxygen by chemisorption.

A power generation system for an aircraft includes: a storage tank for storing hydrogen; a fuel cell configured to generate power from the hydrogen; a fuel supply line configured to supply the hydrogen from storage tank to the fuel cell; a fresh air supply line configured to supply air to a cabin air supply system; and a fuel-air heat exchange system, wherein the fuel supply line and the air supply line pass through the fuel-air heat exchange system such that the hydrogen cools the air in use.

An air processing system for an aircraft comprising a hydrogen fuel cell. The air processing system includes an input airflow; a first and a second compressor, wherein each compressor is configured to compress the airflow in a compression stage; a first and a second turbine, wherein each turbine is configured to decompress the airflow in a decompression stage; and a first and a second shaft each configured to independently rotate. Each shaft mechanically couples one of the compressors and one of the turbines, such that torque can be transferred between the compressor-turbine pair.

Fuel tank inerting systems and methods for aircraft are provided. The systems include a fuel tank, a first reactant source fluidly connected to the fuel tank, the first source arranged to receive fuel from the fuel tank, a second reactant source, a catalytic reactor arranged to receive a first reactant from the first source and a second reactant from the second source to generate an inert gas that is supplied to the fuel tank to fill a ullage space of the fuel tank, and a heating duct connected to the second reactant source, wherein a thermal energy of the second reactant is employed to heat the first reactant source.

Fuel tank inerting systems and methods for aircraft are provided. The systems include a fuel tank, a first reactant source fluidly connected to the fuel tank, the first source arranged to receive fuel from the fuel tank, a second reactant source, a catalytic reactor arranged to receive a first reactant from the first source and a second reactant from the second source to generate an inert gas that is supplied to the fuel tank to fill a ullage space of the fuel tank, and a cool air source arranged to supply cool air to the catalytic reactor to provide thermal control of a reaction within the catalytic reactor, wherein the cool air is discharged from at least one of a cabin of the aircraft and an environmental control system of the aircraft.

Fuel tank inerting systems and methods for aircraft are provided. The systems include a fuel tank, a first reactant source fluidly connected to the fuel tank, the first source arranged to receive fuel from the fuel tank, a second reactant source, wherein the second reactant source is a source of ambient air, and a catalytic reactor arranged to receive a first reactant from the first source and a second reactant from the second source to generate an inert gas that is supplied to the fuel tank to fill a ullage space of the fuel tank.

Fuel tank inerting systems and methods for aircraft are provided. The systems include a fuel tank, a first reactant source fluidly connected to the fuel tank, the first source arranged to receive fuel from the fuel tank, a second reactant source, a catalytic reactor arranged to receive a first reactant from the first source and a second reactant from the second source to generate an inert gas that is supplied to the fuel tank to fill a ullage space of the fuel tank, and a back pressure flow restrictor positioned within or along a fuel tank supply line and downstream of the catalytic reactor, the back pressure flow restrictor arranged to maintain high-pressure operation of the catalytic reactor.

An electronics cooling system for an aircraft includes a heat exchanger comprising a coolant circuit, an air circuit, and a fuel circuit such that each of the circuits is in thermal communication with at least one of the other circuits. The coolant circuit is in thermal communication with one or more aircraft electronics. The air circuit is in fluid communication with at least one air source. The fuel circuit is in fluid communication with a fuel tank between the fuel tank and an engine of the aircraft.