Patent Description:
A typical commercial aircraft includes at least several nonintegrated cooling systems configured to provide temperature control to various regions of the aircraft. For example, an aircraft environmental control system primarily provides heating and cooling for the aircraft cabin area. In addition, a galley chiller system is dedicated to refrigerating the food carts in the galleys located throughout the aircraft. Since each system has a significant weight and power requirement, the overall efficiency of the aircraft is affected by these nonintegrated systems.

One of the more of these cooling systems may rely on ram or fresh air to condition, i.e., to cool or heat another medium. However, in applications where the aircraft is travelling at supersonic speeds, the temperature of the ram air may be too high to effectively remove heat from another load.

<CIT> (prior art under Article <NUM>(<NUM>) EPC) relates to thermal management of one or more loads of a vehicle.

<CIT> relates to an environmental control system of an aircraft.

<CIT> relates to an environmental control system utilizing shoestring cycle to maximize efficiency. <CIT> relates to an environmental control system utilizing bleed pressure assist. <CIT> relates to systems and methods for improving low inlet pressure cooling performance of an air cycle machine (ACM) pack system in a bleed air based aircraft air conditioning system.

According to an embodiment, an environmental control system of a vehicle is provided as claimed in claim <NUM> and includes a first inlet configured to receive a flow of a first medium, a second inlet configured to receive a flow of a second medium, and a thermodynamic device including a compressor and at least one turbine operably coupled by a shaft. The compressor and the at least one turbine are fluidly coupled to the first inlet. The compressor and the at least one turbine are arranged in parallel relative to the flow of the first medium such that a first portion of the first medium is receivable at the compressor and a second portion of the first medium is receivable at the at least one turbine.

In further embodiments the thermodynamic device further comprises an outlet fluidly connected with one or more loads of the vehicle, wherein only the first portion of the first medium is provided to the outlet.

The system comprises a cooling circuit including at least one cooling heat exchanger, the cooling circuit being fluidly connected to the second inlet.

In further embodiments the thermodynamic device further comprises a fan mounted to the shaft and the fan is operable to move the flow of the second medium through the cooling circuit.

The at least one cooling heat exchanger further comprises a primary heat exchanger and a secondary heat exchanger. A cooled flow inlet of the primary heat exchanger is arranged downstream from and is fluidly connected to a cooled flow outlet of the secondary heat exchanger relative to the flow of the second medium.

In further embodiments a heated flow inlet of the secondary heat exchanger is arranged downstream from and is fluidly connected to a heated flow outlet of the primary heat exchanger relative to the flow of the first medium.

In further embodiments a heated flow inlet of the secondary heat exchanger is arranged downstream from and is fluidly coupled to the compressor.

The system comprises at least one regeneration heat exchanger arranged downstream from the at least one cooling heat exchanger relative to the flow of the first medium.

The at least one regeneration heat exchanger further comprises a primary regeneration heat exchanger and a secondary regeneration heat exchanger. The primary regeneration heat exchanger is arranged downstream from the primary heat exchanger relative to the flow of the first medium, and the secondary regeneration heat exchanger is arranged downstream from the secondary heat exchanger relative to the flow of the first portion of the first medium.

In further embodiments the at least one turbine further comprises a first turbine and a second turbine. The compressor and the first turbine are arranged in parallel relative to the flow of the first medium and the second turbine is arranged in series with the compressor relative to the first portion of the first medium.

In further embodiments the vehicle is an aircraft.

In further embodiments the vehicle is operable in a supersonic cruise condition.

A method of operating an environmental control system of a vehicle is provided as claimed in claim <NUM> and includes providing a thermodynamic device including a compressor and a first turbine operably coupled by a shaft, cooling a first medium with a cooling circuit via a second medium, compressing a first portion of the first medium within the compressor to form a compressed first portion of the first medium, expanding a second portion of the first medium at the first turbine to form an expanded second portion of the first medium, and cooling the first medium with the expanded second portion of the first medium.

In further embodiments the method comprises expanding the compressed first portion of the first medium at a second turbine to form an expanded first portion of the first medium, the second turbine being operably coupled to the compressor and the first turbine by the shaft.

In further embodiments the method comprises providing only the expanded first portion of the first medium to at least one load of the vehicle via an outlet.

In further embodiments the method comprises cooling the compressed first portion of the first medium within the cooling circuit via the second medium.

In further embodiments the method comprises cooling the compressed first portion of the first medium with the expanded second portion of the first medium.

In further embodiments the method comprises moving the second medium through the cooling circuit via a fan, the fan being operably coupled to the compressor and the first turbine via the shaft.

In further embodiments the first medium is a pressurized medium.

With reference to the accompanying drawings, like elements are numbered alike:
The FIGURE is a schematic diagram of a cooling system of a vehicle according to an embodiment.

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 Figure.

With reference now to the Figure, an example of a schematic diagram of a portion of an environment control system (ECS) <NUM>, such as an air conditioning unit or pack for example, is depicted according to a non-limiting embodiment. Although the environmental control system <NUM> is 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 ECS <NUM> is configured to receive a first medium A1 at a first inlet <NUM> and may provide a conditioned form of a portion of the first medium A1 to a volume during normal operation. In embodiments where the ECS <NUM> is used in an aircraft application, the first medium A1 is a pressurized flow. The first medium may be a flow of fresh air that has been pressurized in a cabin air compressor located upstream from the inlet <NUM>. In other embodiments, the first medium A1 is bleed air, which is pressurized air originating from, i.e. being "bled" from, an engine or auxiliary power unit of the aircraft. It shall be understood that one or more of the temperature, humidity, and pressure of the bleed air can vary based upon the compressor stage and revolutions per minute of the engine or auxiliary power unit from which the air is drawn.

The ECS <NUM> is configured to receive a second medium A2 at a second inlet <NUM>. In an embodiment, the second medium A2 is 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 second inlet <NUM> can be considered a fresh or outside air inlet. In an embodiment, the second medium A2 is ram air drawn from a portion of a ram air circuit to be described in more detail below. Generally, the second medium A2 described herein is 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.

As shown, the ECS <NUM> includes a cooling circuit <NUM> within which one or more heat exchangers are located. 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 cooling circuit may be referred to as cooling heat exchangers. The at least one cooling heat exchanger includes a first or primary heat exchanger <NUM> and a second or secondary heat exchanger <NUM>. Within the heat exchangers <NUM>, <NUM>, the second medium A2 acts as a heat sink to cool a medium passing there through, for example the first medium A1. Although a cooling circuit <NUM> having only two heat exchangers <NUM>, <NUM> is illustrated, it should be understood that embodiments having more than two heat exchangers are also contemplated herein. Further, although the cooling heat exchangers are illustrated as two separate components, embodiments where the primary and secondary heat exchangers are integrally formed or contained within a single unit are also contemplated herein.

The ECS <NUM> additionally includes at least one regeneration heat exchanger. A first or primary regeneration heat exchanger <NUM> is arranged downstream from the primary heat exchanger <NUM> relative to a flow of the first medium A1. A second or secondary regeneration heat exchanger <NUM> is arranged downstream from the secondary heat exchanger relative to a flow of the first portion A1a of the first medium A1. Although the primary and secondary regenerative heat exchangers are illustrated as two separate components, embodiments where the primary and secondary regenerative heat exchangers are integrally formed or contained within a single unit are also contemplated herein. Further, it should be understood that embodiments where the primary heat exchanger <NUM> and the primary regeneration heat exchanger <NUM> are integrally formed or contained within a single unit and/or embodiments where the secondary heat exchanger <NUM> and the secondary regeneration heat exchanger <NUM> are integrally formed or contained within a single unit are also within the scope of the disclosure.

The ECS <NUM> additionally includes at least one thermodynamic device <NUM>. The thermodynamic device <NUM> is 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 and/or the second medium A2 by raising and/or lowering pressure and by raising and/or lowering temperature). Examples of a thermodynamic device <NUM> include an air cycle machine, a two-wheel air cycle machine, a three-wheel air cycle machine, a four-wheel air cycle machine, etc..

The thermodynamic device <NUM> includes a compressor <NUM> and at least one turbine operably coupled by a shaft <NUM>. In the illustrated, non-limiting embodiment, the thermodynamic device <NUM> includes two turbines <NUM> and <NUM> mounted coaxially, to shaft <NUM>. A compressor <NUM> is 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 turbines <NUM> and <NUM> for example, are mechanical devices that expand a medium and extracts work therefrom (also referred to as extracting energy) to drive the compressor <NUM> via the shaft <NUM>. In an embodiment, the thermodynamic device <NUM> includes a fan <NUM>. The fan <NUM> is a mechanical device that can force via push or pull methods air through the heat exchangers <NUM>, <NUM> at a variable cooling to control temperatures.

The elements of the ECS <NUM> are 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 ECS <NUM> can be regulated to a desired value. For instance, a first valve V1 may be opened when the aircraft is on the ground to provide additional cooling to the regeneration heat exchangers. A second valve V2 is configured to control the temperature of the air provided to the cabin <NUM>.

A method of operating the environmental control system <NUM> when the vehicle is in a first mode at a high altitude, such as during a supersonic cruise condition for example, is described. During operation of the ECS <NUM>, the second medium A2 is provided to the inlet <NUM>. As shown, the second medium A2 is provided to a cooled flow inlet <NUM> of the secondary heat exchanger <NUM>. As will be described in more detail below, the second medium A2 is configured to cool a flow of the first medium A1 within the secondary heat exchanger <NUM>. Accordingly, a temperature of the second medium A2 provided at the cooled flow outlet <NUM> of the secondary heat exchanger <NUM> is increased compared to that provided to the cooled flow inlet <NUM>. The second medium A2 is provided to the secondary heat exchanger <NUM> and the primary heat exchanger <NUM> in series, and in some embodiments, the primary heat exchanger <NUM> is arranged directly downstream from the cooled flow outlet <NUM> of the secondary heat exchanger <NUM>. From the secondary heat exchanger <NUM>, the second medium A2 is provided to the cooled flow inlet <NUM> of the primary heat exchanger <NUM>. As will be described in more detail below, the second medium A2 is configured to cool a flow of the first medium A1 within the primary heat exchanger <NUM>. Accordingly, a temperature of the second medium A2 provided at the cooled flow outlet <NUM> of the primary heat exchanger <NUM> is increased compared to that provided to the cooled flow inlet <NUM>.

The fan <NUM> of the thermodynamic device <NUM> may be arranged in fluid communication with and positioned downstream from both the primary and the secondary heat exchangers <NUM>, <NUM> relative to the flow of the second medium A2. In an embodiment, operation of the fan <NUM> is configured to draw the flow of the second medium A2 from the inlet <NUM> through the secondary heat exchanger <NUM> and the primary heat exchanger <NUM>, respectively. Once the second medium A2 has passed through the fan <NUM>, the second medium A2 may be exhausted overboard, or alternatively, may be provided to another system of the vehicle.

The pressurized first medium A1 provided to the first inlet <NUM>, such as from a first source for example, is configured to flow to a heated flow inlet <NUM> of the primary heat exchanger <NUM>. Within the primary heat exchanger <NUM>, the hot pressurized medium A1 is arranged in a heat exchange relationship with the second medium A2. Because the second medium A2 is much cooler than the first medium A1 at the primary heat exchanger <NUM>, heat is configured to transfer from the first medium A1 to the second medium A2 therein. Accordingly, the temperature of the first medium A1 at the heated flow outlet <NUM> of the primary heat exchanger <NUM> is less than at the heated flow inlet <NUM>.

In the illustrated, non-limiting embodiment, the first medium A1 is configured to flow through the primary heat exchanger <NUM> and the primary regeneration heat exchanger <NUM> in series. Further, in some embodiments, the primary regeneration heat exchanger <NUM> is arranged directly downstream from the heated flow outlet <NUM> of the primary heat exchanger <NUM>.

From the primary heat exchanger <NUM>, the first medium A1 is provided to the heated flow inlet <NUM> of the primary regeneration heat exchanger <NUM>. As will be described in more detail below, the first medium A1 is arranged in a heat exchange relationship with an expanded second portion A1b of the first medium A1 at the primary regeneration heat exchanger <NUM>. Accordingly, heat from the first medium A1 is transferred to the expanded first medium A1 within the primary regeneration heat exchanger <NUM>.

The heated flow outlet <NUM> of the primary regeneration heat exchanger <NUM> is fluidly coupled to at least one wheel of the thermodynamic device <NUM>. In the illustrated, non-limiting embodiment, the heated flow outlet <NUM> of the primary regeneration heat exchanger <NUM> is fluidly coupled to both the compressor <NUM> and the first turbine <NUM> of the thermodynamic device <NUM>. Accordingly, downstream from the heated flow outlet <NUM> and upstream from the thermodynamic device <NUM>, the flow of the first medium A1 is split into a first portion A1a provided to an inlet <NUM> of the compressor <NUM> and a second portion A1b provided to an inlet <NUM> of the first turbine <NUM>.

Within the first turbine <NUM>, the cool pressurized second portion A1b of the first medium A1 is expanded across the first turbine <NUM> and work is extracted therefrom. This extracted work is used to drive the shaft <NUM>, thereby driving the compressor <NUM>, and also the fan <NUM> to move the second medium A2 through the primary heat exchanger <NUM> and the secondary heat exchanger <NUM> as previously described. From the outlet <NUM> of the first turbine <NUM>, the expanded second portion A1b of the first medium A1 is provided to a cooled flow inlet <NUM> of the secondary regeneration heat exchanger <NUM>. Within the expanded second portion A1b of the first medium A1 is configured to cool a flow of compressed first portion A1a of the first medium A1 at the secondary regeneration heat exchanger <NUM>. Therefore as a result of absorbing heat, the expanded second portion A1b of the first medium A1 provided at the cooled flow outlet <NUM> of the secondary regeneration heat exchanger <NUM> is warmer than at the cooled flow inlet <NUM>.

In the illustrated, non-limiting embodiment, the expanded second portion A1b of the first medium A1 is configured to flow through the secondary regeneration heat exchanger <NUM> and the primary regeneration heat exchanger <NUM> in series. Further, in some embodiments, the primary regeneration heat exchanger <NUM> is arranged directly downstream from the cooled flow outlet <NUM> of the secondary regeneration heat exchanger <NUM> relative to the flow of the expanded second portion A1b of the first medium A1. The expanded second portion A1b of the first medium A1 provided to the cooled flow inlet <NUM> of the primary regeneration heat exchanger <NUM> is arranged in a heat exchange relationship with the first medium A1. Heat from the warm first medium A1 is configured to transfer to the expanded second portion A1b of the first medium A1, thereby cooling the first medium A1. Accordingly, the temperature of the expanded second portion A1b of the first medium A1 provided at the cooled flow outlet <NUM> of the primary regeneration heat exchanger <NUM> is greater than at the cooled flow inlet <NUM>. From the cooled flow outlet <NUM>, the expanded second portion A1b of the first medium A1 may be exhausted overboard, or alternatively, may be provided to another system of the vehicle.

The cool pressurized first portion A1a of the first medium A1 is provided to the compressor <NUM>. The act of compressing the first portion A1a of the first medium A1 heats the first portion A1a to form a compressed first portion A1a of the first medium A1. From the outlet <NUM> of the compressor <NUM>, the compressed first portion A1a of the first medium A1 is provided to a heated flow inlet <NUM> of the secondary heat exchanger <NUM>. Within the secondary heat exchanger <NUM>, the compressed first portion A1a of the first medium A1 is cooled via a heat exchange relationship with the second medium A2. Accordingly, the temperature of the compressed first portion A1a of the first medium A1 provided at the heated flow outlet <NUM> of the secondary heat exchanger <NUM> is less than at the heated flow inlet <NUM>.

From the secondary heat exchanger <NUM>, the compressed first portion A1a of the first medium A1 is provided to the heated flow inlet <NUM> of the secondary regeneration heat exchanger <NUM>. Within the secondary regeneration heat exchanger <NUM>, the compressed first portion A1a of the first medium A1 is arranged in a heat exchange relationship with the expanded second portion A1b of the first medium A1. Because the compressed first portion A1a of the first medium A1 is hotter than the expanded second portion A1b of the first medium A1, heat transfers from the compressed first portion A1a of the first medium A1 to the expanded second portion A1b of the first medium A1.

From the heated flow outlet <NUM> of the secondary regeneration heat exchanger <NUM>, the compressed first portion A1a of the first medium A1 is provided to a water extractor <NUM>, where any free moisture is removed. The resulting cool, dry, compressed first portion A1a of the first medium A1 is then provided to the second turbine <NUM>. Within the second turbine <NUM>, the compressed second portion A1b of the first medium A1 is expanded and work is extracted therefrom. This extracted work is used to drive the shaft <NUM>, thereby driving the compressor <NUM>, and also the fan <NUM> to move the second medium A2 through the primary heat exchanger <NUM> and the secondary heat exchanger <NUM> as previously described. The resulting expanded first portion A1a of the first medium A1 output from the outlet of the second turbine <NUM> may then be delivered to one or more loads of the vehicle, such as to the cabin for example.

An environmental control system <NUM> as illustrated and described herein is particularly beneficial in applications where the first medium A1 provided at the first inlet <NUM> of the ECS <NUM> is not sufficiently pressurized for delivery to one or more loads of the aircraft.

Claim 1:
An environmental control system for a vehicle comprising:
a first inlet (<NUM>) configured to receive a flow of a first medium (A1);
a second inlet (<NUM>) configured to receive a flow of a second medium (A2);
a thermodynamic device (<NUM>) including a compressor (<NUM>) and at least one turbine operably coupled by a shaft (<NUM>), wherein the compressor and the at least one turbine are fluidly coupled to the first inlet, the compressor and the at least one turbine being arranged in parallel relative to the flow of the first medium such that a first portion (A1a) of the first medium is provided to the compressor and a second portion (A1b) of the first medium is provided to the at least one turbine;
a cooling circuit (<NUM>) including at least one cooling heat exchanger, the cooling circuit being fluidly connected to the second inlet (<NUM>);
wherein the at least one cooling heat exchanger further comprises a primary heat exchanger (<NUM>) and a secondary heat exchanger (<NUM>), characterised in that a flow inlet (<NUM>) of the primary heat exchanger is arranged downstream from and is fluidly connected to a flow outlet (<NUM>) of the secondary heat exchanger relative to the flow of the second medium (A2);
and in that the system further comprises at least one regeneration heat exchanger (<NUM>, <NUM>) arranged downstream from the at least one cooling heat exchanger relative to the flow of the first medium (A1);
wherein the at least one regeneration heat exchanger further comprises a primary regeneration heat exchanger (<NUM>) and a secondary regeneration heat exchanger (<NUM>), the primary regeneration heat exchanger being arranged downstream from the primary heat exchanger (<NUM>) relative to the flow of the first medium (A1), and the secondary regeneration heat exchanger being arranged downstream from the secondary heat exchanger (<NUM>) relative to the flow of the first portion of the first medium.