Bleedless Environmental Control System

This application claims the benefit of U.S. Application No. 63/573,062 filed Apr. 2, 2024, the contents of which are incorporated by reference herein in its entirety.

Embodiments of the disclosure relate to environmental control systems, and more specifically to an environmental control system of an aircraft.

In general, contemporary air condition systems are supplied a pressure at cruise that is approximately 30 psig to 35 psig. The trend in the aerospace industry today is towards systems with higher efficiency. One approach to improve airplane efficiency is to eliminate the bleed air entirely and use electrical power to compress outside air. A second approach is to use lower engine pressure. The third approach is to use the energy in the bleed air to compress outside air and bring it into the cabin. Unfortunately, each of these approaches provides limited efficiency with respect to engine fuel burn.

According to an embodiment, an environmental control system of a vehicle includes an air conditioning system having a first inlet for a first medium, a second inlet for a second medium, and a first thermodynamic device including a first compressor, a first electric motor and a first turbine operably coupled by a first shaft. An air supply system includes a second thermodynamic device fluidly coupled to the air conditioning system. The second thermodynamic device includes a second compressor operably coupled to a second electric motor by a second shaft. The second thermodynamic device is fluidly coupled to and is arranged upstream from the first inlet relative to a flow of the first medium and is fluidly coupled to and is arranged downstream from the second inlet relative to a flow of the second medium. The second electric motor is fluidly coupled to and is cooled by the second medium provided at the second inlet.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments the flow of the second medium is configured to make a plurality of passes over the second electric motor.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments the second thermodynamic device includes a second turbine operably coupled to the second compressor and the second electric motor by the second shaft.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments the second turbine is arranged directly downstream from the second electric motor relative to the flow of the second medium.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments the air conditioning system includes a ram air circuit having at least one ram heat exchanger and an outlet of the second turbine is fluidly connected to the ram air circuit at a location downstream from the at least one ram heat exchanger.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments the second compressor has a second compressor outlet being fluidly connected to and arranged in series with the at least one ram heat exchanger.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments a high-pressure water separator is positioned directly downstream from the at least one ram heat exchanger.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments in a first mode, the second compressor is driven solely by the second electric motor

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments in a second mode, the second compressor is driven by the second electric motor and by energy extracted from the second medium at the second turbine.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments the first electric motor is fluidly connected to the second inlet such that at least a portion of the second medium is provided to the first electric motor to cool the first electric motor.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments the first electric motor is fluidly connected to the second electric motor in series relative to the flow of the second medium.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments the environmental control system is part of an aircraft and the first medium is fresh air.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments the second medium is cabin air.

According to an embodiment, a method of operating an environmental control system of a vehicle includes compressing a first medium at an air supply system to form a compressed first medium. The air supply system includes a thermodynamic device fluidly coupled to an air conditioning system. The thermodynamic device includes a compressor and an electric motor operably coupled to the electric motor by the shaft. The method includes cooling the electric motor via a flow of second medium provided from the air conditioning system and delivering both the compressed first medium and the flow of second medium to a ram air circuit of the air conditioning system from the air supply system. The ram air circuit includes at least one ram heat exchanger and the flow of second medium is delivered to the ram air circuit downstream from the at least one ram heat exchanger.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments the at least one ram heat exchanger includes a plurality of ram heat exchangers and the flow of second medium is delivered to the ram air circuit downstream from each of the plurality of ram heat exchangers.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments cooling the compressed first medium within the at least one ram heat exchanger.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments cooling the compressed first medium within the at least one ram heat exchanger includes drawing a flow of ram air through the ram air circuit via a fan.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments extracting energy from the flow of second medium at the thermodynamic device to form an expanded second medium. The extracting energy occurs directly downstream from cooling the electric motor.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments the air conditioning system includes another thermodynamic device including another compressor, another electric motor, and a turbine operably coupled by another shaft, and cooling the another electric motor via the flow of second medium.

In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments cooling the another electric motor via the flow of second medium occurs after cooling the electric motor with the flow of second medium.

A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the FIGS.

Embodiments herein provide an environmental control system of an aircraft that receives multiple mediums from different sources and uses energy from one or more of the mediums to operate the environmental control system and to provide cabin pressurization and cooling at a high fuel burn efficiency. The mediums described herein are generally types of air; however, it should be understood that other mediums, such as gases, liquids, fluidized solids, or slurries are also contemplated herein.

With reference now to the, examples of a schematic diagram of a portion of an environment control system (ECS)are depicted according to a non-limiting embodiment. Although the environmental control system or ECSis described with reference to an aircraft, alternative applications, such as another vehicle for example, are also within the scope of the disclosure. As shown, the environmental control systemmay include an air conditioning systemhaving one or more air conditioning system (ACS) packs for example, are depicted according to a non-limiting embodiment. Although only a single ACS packis illustrated, it should be understood that the ECSmay include additional ACS packshaving similar configurations to those illustrated and described herein.

The ACS packmay be configured to receive the first medium A1 at a first inletand may provide a conditioned form of the first medium A1 to a volumeduring normal operation. In embodiments where the ECSis used in an aircraft application, the first medium A1 may be fresh air, such as outside air for example. The outside air can be procured via one or more scooping mechanisms, such as an impact scoop or a flush scoop for example. Thus, the inletcan be considered a fresh or outside air inlet. In an embodiment, the first medium A1 is ram air drawn from a portion of a ram air circuit. Generally, the first medium A1 described herein may be at an ambient pressure equal to an air pressure outside of the aircraft when the aircraft is on the ground and is between an ambient pressure and a cabin pressure when the aircraft is in flight.

The ACSmay alternatively or additionally be configured to receive a second medium A2 at a second inlet. In an embodiment, the second inletis operably coupled to a volume, such as the cabin of an aircraft, and the second medium A2 is cabin discharge air, which is air leaving the volume and that would typically be discharged overboard. In some embodiments, the ACSis configured to extract work from the second medium A2. In this manner, the second medium A2 of the volumecan be utilized by the ACSto achieve certain operations. However, it should be understood that embodiments where another medium is used as either the first and/or second medium, are also within the scope of the disclosure. In an embodiment, the ECSdoes not receive a flow of bleed air from either an engine or an auxiliary power unit.

The ACSincludes a RAM air circuitincluding a shell or duct, illustrated schematically at, within which one or more heat exchangers are located. The shellcan receive and direct a medium, such as ram air AR for example, through a portion of the ACS. The one or more heat exchangers are devices built for efficient heat transfer from one medium to another. Examples of the type of heat exchangers that may be used, include, but are not limited to, double pipe, shell and tube, plate, plate and shell, adiabatic shell, plate fin, pillow plate, and fluid heat exchangers.

The one or more heat exchangers arranged within the shellmay be referred to as ram heat exchangers. In the illustrated, non-limiting embodiment, the at least one ram heat exchanger is a plurality of ram heat exchangers including a first heat exchangerand a second heat exchanger. However, any suitable number of heat exchangers may be contemplated herein. Within the heat exchangers,, ram air, such as outside air for example, acts as a heat sink to cool a medium passing there through, for example the first medium A1. Although the plurality of ram air heat exchangers,are illustrated as being arranged in series relative to a flow through the ram air circuit, it should be understood that in other embodiments, the plurality of heat exchangers may be arranged in parallel or some combination of series and parallel.

The ACSadditionally includes at least one thermodynamic device, and in some embodiments includes a plurality of thermodynamic devices. Each thermodynamic deviceis a mechanical device that includes components for performing thermodynamic work on a medium (e.g., extracts work from or applies work to the first medium A1, by raising and/or lowering pressure and by raising and/or lowering temperature). Examples of a thermodynamic device include an air cycle machine, a two-wheel air cycle machine, a three-wheel air cycle machine, a four-wheel air cycle machine, etc.

In the illustrated, non-limiting embodiments, the ACSincludes a single thermodynamic device. However, embodiments including two or more thermodynamic devices are also contemplated herein. The thermodynamic devicemay include a compressorand at least one turbine operably coupled thereto by a shaft. In the non-limiting embodiments shown in the FIGS., the thermodynamic deviceincludes a single turbine. However, embodiments including a plurality of turbines are also within the scope of the disclosure.

The compressoris a mechanical device configured to raise a pressure of a medium and can be driven by another mechanical device (e.g., a motor or a medium via a turbine). Examples of compressor types include centrifugal, diagonal or mixed-flow, axial-flow, reciprocating, ionic liquid piston, rotary screw, rotary vane, scroll, diaphragm, air bubble, etc. A turbine, such as turbinefor example, is a mechanical device that expands a medium and extracts work therefrom (also referred to as extracting energy). This extracted energy is transmitted to the shaft of the turbine and the other components operably coupled thereto, such as a compressorfor example.

In an embodiment, the ACSincludes a fan. A fanis a mechanical device that can force via push or pull methods air through the shell of the ram air duct, across at least a portion of the ram air heat exchangers. The fanmay be a component separate from a thermodynamic devicedriven by any suitable means, such as a motor for example. However, in other embodiments, the fanmay be operably coupled to the thermodynamic device. For example, in the non-limiting embodiment of, the fanis coupled to and is driven by the shaftof the thermodynamic device. Integration of the faninto the thermodynamic deviceeliminates the weight of the electric motor and the motor controller needed to drive a separate electric ram fan.

Alternatively, or in addition to the turbine, the thermodynamic devicemay have an electric motoroperably coupled to the compressorvia the rotatable shaft. The motormay be used as an alternative to, or in combination with, the energy extracted from the turbinecoupled thereto via a respective shaft. The motormay supply pressure to the first medium A1 via a respective compressorbased on the cooling and pressurization needs of the cabin.

The elements of the ACSare connected via valves, tubes, pipes, and the like. Valves (e.g., flow regulation device or mass flow valve) are devices that regulate, direct, and/or control a flow of a medium by opening, closing, or partially obstructing various passageways within the tubes, pipes, etc. of the system. Valves can be operated by actuators, such that flow rates of the medium in any portion of the system can be regulated to a desired value.

The ECSmay additionally include an air supply systemfluidly connected to the ACSrelative to a flow of the first medium A1. In the illustrated non-limiting embodiment, the air supply systemis located upstream from the inletof the ACSrelative to the flow of the first medium A1. The air supply systemmay include another thermodynamic device, such as a cabin air compressor (CAC) including a compressordriven by another component. As shown in, the compressormay be driven by an electric motoroperably coupled thereto. In the illustrated, non-limiting embodiment, the motoris connected to the compressorby a rotatable shaft. However, in other embodiments, such as shown in, as an alternative to or in addition to the motor, the thermodynamic deviceof the air supply systemmay include a turbineoperably coupled to the compressor, such as via the shaft. In such embodiments, energy extracted from a second medium A2 within the turbinemay be used to drive the compressor. Accordingly, in a first mode of operation, the compressorof the air supply systemmay be driven solely by the electric motorand in a second mode of operation, the compressormay be driven by the electric motor and the turbine, in combination. Embodiments where the system is alternatively or additionally operable in a mode where the compressoris solely powered by the turbineare also contemplated herein.

During operation of the ECSof, a flow of first medium A1 is received at an inlet. From the inlet, the first medium A1 is provided to the compressorof the thermodynamic device. The act of compressing the first medium A1 heats it. The resulting compressed first medium A1′ is provided to the inletof the downstream ACS. From the inlet, the flow of compressed first medium A1′ is provided to the primary heat exchangerof the ram air circuit. A flow of ram air, moving through the ram air ductvia operation of the fan, is provided to the primary heat exchangerto cool the compressed first medium A1′. The outlet of the heat exchangeris fluidly connected to an inlet of the compressorof the thermodynamic device. The cool compressed first medium A1′ output from the heat exchangeris further compressed within the compressor, such that the compressed first medium A1′ output from the compressorhas a higher temperature and/or pressure than the compressed first medium A1′ provided to the inlet of the compressor.

An outlet of the compressoris fluidly connected to an inlet of the secondary heat exchanger. Accordingly, the compressed first medium A1′ output from the compressoris provided to an inlet of the secondary heat exchanger. Similar to the primary heat exchanger, the compressed first medium A1′ is cooled within the secondary heat exchangerby a flow of ram air. In an embodiment, the compressed first medium A1′ is cooled within the secondary heat exchangerto approximately ambient temperature.

In the illustrated, non-limiting embodiment, a high-pressure water separator, illustrated schematically at, is located directly downstream from the outlet of secondary heat exchanger. Further, the high-pressure water separatoris arranged upstream from the turbinerelative to the flow of the compressed first medium A1′. The high-pressure water separatormay include a condensing heat exchanger and a water extractor arranged in series. The cool compressed first medium A1′ from the secondary heat exchangeris configured to enter the condensing heat exchanger, where it is cooled by a flow of expanded first medium A1″ output from the first turbine, to be described in more detail below. As the compressed first medium A1′ is cooled within the condensing heat exchanger, moisture is condensed from the compressed first medium A1′. The compressed first medium A1′ then enters a water extractor where any free moisture in the compressed first medium A1′ is removed. The resulting cool, dry, compressed first medium A1′ is then provided to an inlet of the turbinewhere it is expanded and work is extracted therefrom to form an expanded first medium A1″. The work extracted within the turbinemay be used to drive the compressor. The act of extracting work from the compressed first medium A1′ within the turbinecools the compressed first medium A1′.

From the turbine, the expanded first medium A1″ is configured to make a second pass through the condensing heat exchanger of the high-pressure water separator. Within the condensing heat exchanger, the expanded first medium A1″ absorbs heat from the compressed first medium A1′ output from the secondary heat exchanger. The warmed expanded first medium A1″ output from the condensing heat exchanger can then be delivered to one or more downstream loads, such as the cabin, flight deck or other aircraft systems for example.

At the same time, a flow of second medium A2 may be provided to the ACSvia the second inlet. As shown, the second medium A2 is used to remove heat from the motorof the thermodynamic deviceof the air supply systembefore being exhausted overboard or dumped into the ram air circuit, such as at a location downstream from the heat exchangers,.

In the non-limiting embodiment shown in, when the aircraft is at altitude, the second medium A2, after absorbing heat from the motor, is provided to the turbine. In an embodiment, the temperature of the second medium A2 at an inlet of the turbineis above 100° F. Within the turbine, the second medium A2 is expanded and work is extracted therefrom to form an expanded second medium A2″. The work extracted within the turbinemay augment the power of the motorused to drive the compressor. Accordingly, inclusion of the turbineand the extraction of energy from the second medium A2 therein may reduce the power needed by the motorto drive the compressorby as much as 30%. This reduction in power may lower the power provided by controller associated with the motor, thereby lowering its heat rejection. This lowers the heat load on separate a liquid cooling loop and in some embodiments, may eliminate the need for the liquid cooling loop all together.

In an embodiment, the second medium A2 may also be used to cool the motorof the thermodynamic deviceof the ACS. In such embodiments, the flow of the second medium A2 may be divided into a first portion provided to the motorof the thermodynamic deviceand a second portion provided to the thermodynamic deviceof the air supply system. In other embodiments, the second medium A2 may be used to cool the motors,in series. For example, the expanded second medium A2″ output from the turbineand having already cooled the motormay be configured to make one or more passes over the motorto remove heat therefrom before being exhausted into the ram air circuit. Alternatively, the second medium A2 may be used to cool the motorand then may be delivered to the downstream motorof the thermodynamic device.

An advantage of the ECSdisclosed herein is that the power needed to cool and pressurize the flow provided to the cabinis shared between two motors,and at least one turbine,. This helps to reduce the size of the controllers associated with these motors,, allowing the controllers to also potentially be air-cooled.

The term “about” is intended to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of filing the application.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, element components, and/or groups thereof.

While the present disclosure has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this present disclosure, but that the present disclosure will include all embodiments falling within the scope of the claims.