An environmental control system includes a compression device including a compressor, a turbine, and an electric motor operably coupled by a shaft. The electric motor and the turbine are arranged in series relative to a flow of a first medium.

A shaft for a cabin air compressor includes a first attachment portion, a second attachment portion, an intermediate portion, a retention flange, and a tie rod support pocket. The first attachment portion is disposed at a first end of the shaft. The second attachment portion is disposed at a second end of the shaft opposite the first end. The intermediate portion extends from the first attachment portion to the second attachment portion and an interior wall of the intermediate portion defines an inner shaft space. The retention flange extends a first distance into the inner shaft space from the interior wall of the intermediate portion and is offset from the first attachment portion by a second distance. The tie rod support pocket is defined by the interior wall, extends between the flange and the first attachment portion, and is configured to receive a tie rod support.

Aircraft environmental control systems having electrically powered ram circuit fans are described herein. An example environmental control system includes an air cycle machine to produce cabin air for a cabin of the aircraft. The air cycle machine includes a turbine and a heat exchanger. The environmental control system also includes a ram circuit. The heat exchanger is disposed in the ram circuit. The environmental control system further includes a fan in the ram circuit to control air flow through the ram circuit and across the heat exchanger, an electric motor, and an overrunning clutch operatively coupled between the turbine and the electric motor to enable the turbine to drive the fan during a first mode of operation and to enable the electric motor to drive the fan during a second mode of operation.

An air duct system includes an air duct having a main body. The main body of the air duct defines a passageway and an outer surface. The air duct system also includes one or more thermoelectric generators. Each thermoelectric generator includes a hot side and a cold side, and the hot side of the thermoelectric generator is positioned along the outer surface of the air duct.

An environmental control system (ECS) for an aircraft includes a primary heat exchanger, a compressor including an inlet fluidically connected to the primary heat exchanger, a turbine operatively connected to the compressor, and a cryogenic fluid heat exchanger fluidically connected to the primary heat exchanger.

Aircraft systems including a pressurized fuel tank containing a pressurized fuel, a turbo expander configured to receive the pressurized fuel from the fuel tank, the turbo expander configured to decrease a pressure of the pressurized fuel to generate low pressure fuel having pressure less than the pressurized fuel, a fuel-to-air heat exchanger configured to receive the low pressure fuel from the turbo expander as a first working fluid and air as a second working fluid, the heat exchanger configured to cool the air and warm the fuel, an aircraft cabin configured to receive the cooled air, and a fuel consumption system configured to consume the fuel to generate power.

An environmental control system of a vehicle includes a ram air circuit including a ram air shell having a ram air heat exchanger positioned therein, a dehumidification system arranged in fluid communication with the ram air circuit, a first compression device arranged in fluid communication with the dehumidification system, the first compression device including a first compressor, and a second compression device arranged in fluid communication with the ram air circuit. The second compression device includes a second compressor. A first medium is provided to the first compressor and to the second compressor in series.

An environmental control system of a vehicle including a first inlet for providing a first medium, a second inlet for providing a second medium, a compression device arranged in fluid communication with the first inlet, and an expansion device separate from the compression device. The expansion device is arranged in fluid communication with the second inlet. Energy extracted from the second medium within the expansion device is provided to one or more loads of the vehicle.

A pressurization system includes a first compressor that receives a ram air, a fan air, or engine air; a first turbine that is on a common shaft with the first compressor and wherein the first turbine receives an engine air; a main heat exchanger downstream of the first compressor and the first turbine; an internal environment suitable for human occupants and downstream of the main heat exchanger; a second turbine downstream of the internal environment; the second turbine may be on the common shaft with the first compressor and first turbine; or a generator downstream of the second turbine; a motor downstream of the generator; and wherein the motor drives the first compressor.

An air conditioning pack of a cooling system includes an air cycle machine assembly, a cabin air compressor assembly, and a mixing duct. The air cycle machine assembly includes a compressor configured to receive an air stream that includes bleed air to generate a compressed air stream. The air cycle machine assembly utilizes a first portion of the compressed air stream to power the compressor. The cabin air compressor assembly receives a second portion of the compressed air stream, and utilizes the second portion to generate compressed ram air. The mixing duct receives the compressed ram air and allows the compressed ram air to mix with one or more of the air stream upstream of the compressor or the compressed air stream downstream of the compressor to generate a hybrid air stream that is used for cooling at least a portion of a vehicle.