A method and system for controlling fresh air flow into a controlled environment are disclosed herein. The method comprises: measuring, using a sensor, a predetermined property in the controlled environment; estimating, by a controller, a number of people inside the controlled environment based on the measured property, and setting, by the controller, a rate of fresh air flow to the controlled environment based at least in part on the estimated number of people inside the controlled environment.

An environmental control system includes a refrigerant circuit with a pump segment and an evaporator segment, an evaporator arranged along the evaporator segment and in fluid communication with of the refrigerant circuit, and a coolant circuit. The coolant circuit extends through the evaporator and is thermally coupled to refrigerant circuit by the evaporator, the coolant circuit including a first segment and a second segment arranged in parallel with one another to transfer heat from a first zone to a first portion of liquid coolant traversing the coolant circuit and transfer additional heat from a second zone to a second portion of coolant traversing the coolant circuit. Aircraft and environmental control systems are also described.

A compact, lightweight, low power aircraft air filtration and VOC removal unit enables the removal of VOCs from cabin air in a passenger aircraft. A plurality of baffles having air flow-through airflow spaces are spaced apart along a duct. UV LEDs are mounted on the interior sides of the outermost baffles, and on both sides of all interior baffles. A filter module is disposed between pairs of baffles, and spaced from the baffles sufficiently to illuminate the entirety of both sides. Each filter modules comprises a plurality of filters. The filters are selected from a coarse foam, a fine foam, or a fused quartz filament felt. Each filter is loaded with a catalyst including one or more of AEROXIDE® P25, other pure titanium dioxide (TiO.sub.2), iron-doped TiO.sub.2, carbon-doped TiO.sub.2, and combinations thereof. The catalysts on the filters, under UV illumination, chemically reduce VOCs in the airflow to non-VOC molecules.

A control system for use in controlling a cabin blower system. The cabin blower system includes a gas turbine engine spool, a cabin blower compressor powered by the spool and arranged in use to compress fluid used in a cabin of an aircraft, and one or more control mechanisms via which the control system controls the power extracted by the cabin blower compressor from the spool. The control system is arranged in use to control the power extracted from the spool by the cabin blower compressor in accordance with one or more primary control parameters. The control system is arranged in use to alter the spool power extracted by the cabin blower compressor by comparison with the power that would have been extracted in accordance with the primary control parameters alone, in response to modifications in a secondary control parameter indicative of the commencement or occurrence of an engine transient.

A fuel tank inerting system is provided including an air flow comprising air from a first source having a first temperature and air from a second source having a second temperature. The second temperature is cooler than the first temperature. At least one separating module is configured to separate an inert gas from the air flow.

An aircraft is provided. The aircraft includes a pressurized volume and an air conditioning system. The air conditioning system operates in a first mode or a second mode. The first mode includes when a first medium and a second medium and are mixed and provided to the pressurized volume. The second mode includes when only the first medium is provided to the pressurized volume.

An environmental control system according to an example of the present disclosure includes a heat exchanger, a ram air duct operable to provide cooling ram air to the heat exchanger, and a water extractor operable to extract water from a bleed air stream. The heat exchanger includes at least one nozzle operable to spray water from the water extractor into the ram air duct. An example heat exchanger and a method of making a heat exchanger are also disclosed.

A system for cooling a motor includes a rotary machine and a cooling flow path. The rotary machine includes a motor including a rotor and a stator, a compressor including a compressor rotor, and a shaft extending between the motor and the compressor rotor. The cooling flow path is configured to deliver cooling air from a cabin of an aircraft to the motor.

An aircraft air conditioning pack assembly including an air conditioning pack configured to discharge heat, and an exterior panel positioned in close proximity to the air conditioning pack. The exterior panel includes an opening defined therein, a first side facing towards the air conditioning pack, and a second side defining an exterior surface configured to be in communication with a free stream airflow. At least a portion of the air conditioning pack is disposed within the opening to facilitate transferring heat from the air conditioning pack to the free stream airflow.

An environmental control system for providing a conditioned medium to one or more loads of an aircraft includes an air conditioning system including a compressor for regulating a pressure of a first medium and a turbine operably coupled to the compressor and a pressurized volume containing a second medium. The pressurized volume is arranged in fluid communication with a component of the air conditioning system. At least one valve of the air conditioning system is operable to control a flow of second medium to the turbine, wherein the at least one valve is adjustable to maintain a minimum pressure within the pressurized volume.