Abstract: An environmental control system includes an inlet configured to receive a medium and a compressing device fluidly connected to the inlet. The compressing device includes a compressor operably coupled to a turbine. An outlet of the compressor is fluidly connected to an inlet of the turbine such that the medium is provided to the compressor and the turbine in series. At least one air-liquid heat exchanger is arranged in fluid communication with the outlet of the compressor and the inlet of the turbine. The at least one air-liquid heat exchanger is also connected to a liquid loop containing a liquid. At least one air-liquid regeneration heat exchanger is fluidly connected to the liquid loop at a location upstream from the at least one air-liquid heat exchanger.

Abstract: An environmental control system of a vehicle includes a compressor having a compressor inlet configured to receive a first medium and a compressor outlet. A compressed first medium is provided at the compressor outlet. A conduit is configured to receive a second medium and a heat exchanger is mounted to the compressor. The heat exchanger is fluidly connected to a portion of the compressor and to the conduit.

Abstract: An environmental control system of a vehicle includes a first inlet for receiving a first medium, a second inlet for receiving a second medium, and an outlet for delivering a conditioned medium to a load. A first compression device is configured to receive and compress the first medium and a second compression device is configured to receive and compress the second medium. The first medium and the second medium are mixed together at a mixing point such that a mixture of the first medium and the second medium is the conditioned medium provided at the outlet.

Abstract: A trim module having a first heat exchanger; a second heat exchanger; and a thermoelectric cooler (TEC) module thermally coupled between the heat exchangers; a mix manifold conduit fluidly coupled to the inlet of the first heat exchanger; a zone supply conduit fluidly coupled to the outlet of the first heat exchanger; a cabin return conduit fluidly coupled to the inlet of the second heat exchanger; an exhaust conduit fluidly coupled to the outlet of the second heat exchanger, wherein the TEC module is configured to operate in a first mode or a second mode, depending on a temperature within the zone supply conduit and a target temperature, and in the first mode, the TEC module transfers thermal energy from the first heat exchanger to the second heat exchanger; and in the second mode the TEC module transfers thermal energy from the second heat exchanger to the first heat exchanger.

Abstract: A method of controlling air flow in an environmental control system includes receiving a target total flow value and a combined flow measurement at an outer control loop module. A first air flow reference value is determined based on the target total flow value and the combined flow measurement using the outer control loop module. The first air flow reference value is communicated to an inner control loop module and a flow control valve command determined based at least in part on the first air flow reference value using the inner control loop module. The flow control valve command is communicated to a flow control valve operatively associated with the inner control loop module to control flow through the ECS using the flow control valve. Environmental control systems and computer program products are also described.

Abstract: An environmental control system includes a first inlet for providing a first medium from a first source, a second inlet for providing a second medium from a second source, distinct from the first source, an outlet for receiving a conditioned form of at least one of the first medium and the second medium, and a compression device including a compressor connected to an electric motor by a first shaft. The compressor is arranged in fluid communication with the first inlet and is only driven by the electric motor. An expansion device including a turbine is rotatable about a second shaft distinct from the first shaft. The turbine is arranged in fluid communication with the second inlet.

Abstract: An environmental control system of an aircraft includes a ram air circuit including a ram air shell having a plurality of heat exchangers positioned therein, the plurality of heat exchangers including a first heat exchanger, a second heat exchanger, and a third heat exchanger. The ram air circuit is configured and arranged so that a first medium received at the first heat exchanger passes through the first heat exchanger and then through the third heat exchanger and so that a second medium received at the second heat exchanger passes through the second heat exchanger. A compressing device is arranged in fluid communication with the ram air circuit.

Abstract: An airflow control system includes a valve including a valve disk rotatable within a flow control duct and a valve actuator connected to the valve disk. The valve actuator is operable to adjust a position the valve disk. A pneumatic controller is configured to regulate a pressure within the flow control duct downstream of the valve disk by adjusting the position of the valve disk when the pressure within the flow control duct downstream of the valve disk exceeds a regulation pressure set point. A torque motor is fluidly connected to the valve actuator and a digital controller is operably coupled to the torque motor. The digital controller is configured to regulate the pressure within the flow control duct downstream of the valve disk independently from the pneumatic controller.

Abstract: An aircraft includes one or more engines configured to generate high-pressure bleed air and low-pressure bleed air. An aircraft environmental control system (ECS) is in fluid communication with one or more of the engines to receive the high-pressure bleed air and the low-pressure bleed air. The ECS calculates a synthesized low-pressure value associated with the low-pressure bleed air while still providing bleed air using the high pressure bleed air. The ECS further switches from the high pressure bleed air to the low-bleed pressure air through the ECS while blocking flow of the high-pressure bleed air through the ECS based on the synthesized low-pressure value.

Abstract: A bleed air control system and method include first and second flow paths, first and second flow control valves, and a controller. The first flow path is configured to carry a first bleed air flow and includes a heat transfer device configured to transfer heat to or from the first bleed air flow. The second flow path is configured to carry a second bleed air flow. The first and second flow paths merge downstream to provide a combined bleed air flow. The first flow control valve is positioned to control the first bleed air flow, and the second flow control valve is positioned to control the second bleed air flow. The controller is configured to control the first and second flow control valves to control a temperature and flow of the combined bleed air flow.

Abstract: An aircraft includes a first engine that generates first bleed air flow and a second engine that generates second bleed air flow. The aircraft further includes an aircraft environmental control system (ECS) with a bleed manifold to collect the first bleed air flow and the second bleed air flow, and one or more air cycle machines to perform air conditioning consuming bleed air flow from the bleed manifold. The ECS balances the first bleed air flow and the second bleed air flow output from the first engine and second engine, respectively, based on a bleed manifold pressure of the bleed manifold.

Abstract: A method of controlling air flow in an environmental control system includes receiving a target total flow value and a combined flow measurement at an outer control loop module. A first air flow reference value is determined based on the target total flow value and the combined flow measurement using the outer control loop module. The first air flow reference value is communicated to an inner control loop module and a flow control valve command determined based at least in part on the first air flow reference value using the inner control loop module. The flow control valve command is communicated to a flow control valve operatively associated with the inner control loop module to control flow through the ECS using the flow control valve. Environmental control systems and computer program products are also described.

Abstract: An environmental control system includes a first air flow conduit and a second air flow conduit. A turbine is in fluid communication with the first air flow conduit and a compressor is in fluid communication with the second air flow conduit. The compressor is operatively associated with the turbine. A flow control valve is arranged along the first air flow conduit to control a second air flow in the second air flow conduit according to a first air flow in the first air flow conduit. Aircraft and methods of controlling flow through environmental control systems are also described.

Abstract: A system and method includes a heat exchanger, a ram inlet actuator, and a controller. The ram inlet actuator is configured to control ram air flow from a ram air inlet to the heat exchanger, and the heat exchanger is configured to provide cooling for a bleed air flow. The controller is configured to determine a predicted ram flow based on a bleed air temperature drop across the heat exchanger, a flow rate of the bleed air flow, and a ram air temperature at the ram air inlet. The controller is configured to control the ram inlet actuator based on the predicted ram flow.

Abstract: An aircraft includes a first engine that generates first bleed air flow and a second engine that generates second bleed air flow. The aircraft further includes an aircraft environmental control system (ECS) with a bleed manifold to collect the first bleed air flow and the second bleed air flow, and one or more air cycle machines to perform air conditioning consuming bleed air flow from the bleed manifold. The ECS balances the first bleed air flow and the second bleed air flow output from the first engine and second engine, respectively, based on a bleed manifold pressure of the bleed manifold.

Abstract: An aircraft includes one or more engines configured to generate high-pressure bleed air and low-pressure bleed air. An aircraft environmental control system (ECS) is in fluid communication with one or more of the engines to receive the high-pressure bleed air and the low-pressure bleed air. The ECS calculates a synthesized low-pressure value associated with the low-pressure bleed air while still providing bleed air using the high pressure bleed air. The ECS further switches from the high pressure bleed air to the low-bleed pressure air through the ECS while blocking flow of the high-pressure bleed air through the ECS based on the synthesized low-pressure value.

Abstract: A bleed air control system and method include first and second flow paths, first and second flow control valves, and a controller. The first flow path is configured to carry a first bleed air flow and includes a heat transfer device configured to transfer heat to or from the first bleed air flow. The second flow path is configured to carry a second bleed air flow. The first and second flow paths merge downstream to provide a combined bleed air flow. The first flow control valve is positioned to control the first bleed air flow, and the second flow control valve is positioned to control the second bleed air flow. The controller is configured to control the first and second flow control valves to control a temperature and flow of the combined bleed air flow.

Abstract: A system and method includes a heat exchanger, a ram inlet actuator, and a controller. The ram inlet actuator is configured to control ram air flow from a ram air inlet to the heat exchanger, and the heat exchanger is configured to provide cooling for a bleed air flow. The controller is configured to determine a predicted ram flow based on a bleed air temperature drop across the heat exchanger, a flow rate of the bleed air flow, and a ram air temperature at the ram air inlet. The controller is configured to control the ram inlet actuator based on the predicted ram flow.

Abstract: An electronic expansion valve (EEV) is employed in refrigeration systems to regulate the flow of refrigerant through an evaporator. The position of the EEV is controlled through a first control loop that generates a first position signal based on superheat feedback associated with the refrigeration system, and a second control loop that generates a second position signal based on pressure feedback associated with the refrigeration system. The larger of the first position signal and the second position signal is selected to control the position of the EEV value, and the selected position signal is provided in feedback to both the first control loop and the second control loop.

Abstract: An environmental data recorder includes an enclosure, a first acceleration recorder array positioned on a first inner surface of the enclosure corresponding to an x-z plane defined by an x-axis and a z-axis, a second acceleration recorder array positioned on a second inner surface of the enclosure corresponding to an x-y plane defined by the x-axis and a y-axis, and a third acceleration recorder array positioned on a third inner surface of the enclosure corresponding to a y-z plane defined by the y-axis and the z-axis. The x-axis, the y-axis, and the z-axis are orthogonal axes. The first, second, and third acceleration recorder arrays each include a plurality of beams cantilevered at first ends from a base attached to an inner surface of the enclosure and a plurality of known masses associated with the beams. The beams are configured to deform or break when exposed to different g loads.