A defrost cycle time of an aircraft vapor cycle refrigeration system is adaptively controlled. A pressure of refrigerant at an inlet of a compressor of the vapor cycle refrigeration system is sensed. A defrost cycle of the vapor cycle refrigeration system is initiated in response to the sensed pressure being less than a threshold pressure. The defrost cycle is terminated upon expiration of the defrost cycle time. The defrost cycle time is based upon a time duration of the cooling cycle.

An aircraft humidifier is engineered as a stand-alone, fully integrated aircraft humidifier that is suitable for providing uniform, non-wetting humidified air disbursed by the aircraft humidifier into ambient air to increase the relative humidity in low humidity environments such as aircraft interiors, including cockpits, cabins, crew rests, cargo holds, and lavatories as well as any other enclosed areas.

A method of controlling an outlet temperature of a heat exchanger of an aircraft includes operating an air cycle machine at a first operating speed. The air cycle machine is operatively coupled to an air cycle machine bypass valve at a first position. The air cycle machine is fluidly connected to a first heat exchanger disposed adjacent to a second heat exchanger. In response to a second heat exchanger outlet temperature less than a second heat exchanger outlet temperature threshold while the aircraft is operating at an altitude less than an altitude threshold, the method moves the air cycle bypass valve from the first position toward a second position.

A method of controlling an outlet temperature of a heat exchanger of an aircraft includes operating an air cycle machine at a first operating speed. The air cycle machine is operatively coupled to an air cycle machine bypass valve at a first position. The air cycle machine is fluidly connected to a first heat exchanger disposed adjacent to a second heat exchanger. In response to a second heat exchanger outlet temperature less than a second heat exchanger outlet temperature threshold while the aircraft is operating at an altitude less than an altitude threshold, the method moves the air cycle bypass valve from the first position toward a second position.

A system is provided for an aircraft. This aircraft system includes an aircraft structure, an electrical power storage and an air system. The aircraft structure includes an internal compartment. The electrical power storage is housed within the internal compartment. The air system is configured to direct pressurized air into the internal compartment. The air system includes a plurality of air sources and a flow regulator. The flow regulator is configured to fluidly couple each of the air sources to the internal compartment.