ENVIRONMENTAL CONTROL SYSTEM AND VAPOR CONTROL SYSTEM WATER SEPARATION OVERLAP

An environmental control system of a vehicle includes an inlet configured to receive a medium, a compression device fluidly connected to the inlet, and at least one heat exchanger fluidly connected to the compression device. A secondary fluid system is thermally coupled to the environmental control system. The secondary fluid system has a closed loop configuration through which a secondary fluid circulates. The secondary fluid system includes an evaporator and a condenser. The evaporator has an evaporator outlet fluidly connected to and configured to receive the medium output from an outlet of the heat exchanger outlet and the condenser is connected to the evaporator outlet. The condenser is fluidly connected to and receives the medium output from the evaporator.

BACKGROUND

Exemplary embodiments pertain to an environmental control system of an aircraft, and more particularly, to a vapor compression system thermally coupled to an environmental control system.

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.

BRIEF DESCRIPTION

According to an embodiment, an environmental control system of a vehicle includes an inlet configured to receive a medium, a compression device fluidly connected to the inlet, and at least one heat exchanger fluidly connected to the compression device. A secondary fluid system is thermally coupled to the environmental control system. The secondary fluid system has a closed loop configuration through which a secondary fluid circulates. The secondary fluid system includes an evaporator and a condenser. The evaporator has an evaporator outlet fluidly connected to and configured to receive the medium output from an outlet of the heat exchanger outlet and the condenser is connected to the evaporator outlet. The condenser is fluidly connected to and receives the medium output from the evaporator.

In addition to one or more of the features described herein, or as an alternative, in further embodiments the secondary fluid system is a vapor compression system further comprising a compressor and an expansion device.

In addition to one or more of the features described herein, or as an alternative, in further embodiments comprising a motor operably coupled to the compressor.

In addition to one or more of the features described herein, or as an alternative, in further embodiments the evaporator further comprises a secondary fluid outlet and the condenser further comprises a secondary fluid inlet, the compressor having a compressor inlet connected to the secondary fluid outlet and having a compressor outlet fluidly connected to the secondary fluid inlet.

In addition to one or more of the features described herein, or as an alternative, in further embodiments the condenser further comprises a secondary fluid outlet and the evaporator further comprises a secondary fluid inlet. The expansion device has an expansion device inlet connected to the secondary fluid outlet and has an expansion device outlet fluidly connected to the secondary fluid inlet.

In addition to one or more of the features described herein, or as an alternative, in further embodiments the secondary fluid is a refrigerant.

In addition to one or more of the features described herein, or as an alternative, in further embodiments comprising a water extractor positioned between the evaporator and the condenser relative to a flow of the medium.

In addition to one or more of the features described herein, or as an alternative, in further embodiments the medium is bleed air.

In addition to one or more of the features described herein, or as an alternative, in further embodiments the compression device further comprises a compressor, a turbine, and a shaft operably coupling the compressor and the turbine, wherein work extracted from the medium within the turbine rotates the shaft to power the compressor.

In addition to one or more of the features described herein, or as an alternative, in further embodiments the vehicle is an aircraft.

According to an embodiment, a method of operating an environmental control system includes providing a closed loop secondary fluid system through which a secondary fluid circulates. The secondary fluid system includes an evaporator and a condenser. The secondary fluid system is thermally coupled to the environmental control system. The method additionally includes cooling a medium within the evaporator of the secondary fluid system to from a cooled medium and heating the cooled medium within the condenser of the secondary fluid system.

In addition to one or more of the features described herein, or as an alternative, in further embodiments cooling the medium within the evaporator further comprises transferring heat from the medium to the secondary fluid within the evaporator.

In addition to one or more of the features described herein, or as an alternative, in further embodiments heating the cooled medium within the condenser further comprises transferring heat from the secondary fluid to the cooled medium within the condenser.

In addition to one or more of the features described herein, or as an alternative, in further embodiments a temperature of the cooled medium output from the evaporator is generally 0° C.

In addition to one or more of the features described herein, or as an alternative, in further embodiments comprising removing water from the cooled medium to form a dry medium prior to heating the cooled medium.

In addition to one or more of the features described herein, or as an alternative, in further embodiments removing water from the cooled medium further comprises providing the cooled medium output from the evaporator to a water extractor.

In addition to one or more of the features described herein, or as an alternative, in further embodiments the medium is bleed air.

In addition to one or more of the features described herein, or as an alternative, in further embodiments the secondary fluid system is a vapor compression system.

In addition to one or more of the features described herein, or as an alternative, in further embodiments the secondary fluid is refrigerant.

DETAILED DESCRIPTION

With reference now to theFIG.1, an example of a schematic diagram of a portion of an existing environment control system (ECS)20, such as an air conditioning unit or pack for example, is depicted according to a non-limiting embodiment. Although the environmental control system20is 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 ECS20may be configured to receive a medium A at an inlet22and provide a conditioned form of the medium A to one or more loads24. In embodiments where the ECS20is used in an aircraft application, the medium A may be 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. However, embodiments where the medium A is alternatively or additionally provided from another source are also contemplated. For example, the medium A may be fresh or ambient air such as procured via one or more scooping mechanisms and/or may be cabin air provided from a volume of the aircraft, such as the cabin.

Downstream from the inlet22, the environmental control system20includes at least one heat exchanger. As shown, the medium A may be cooled within a precooler or a first heat exchanger26prior to being delivered to a compressor28. A compressor, such as compressor28is 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. Within the compressor28, the temperature and pressure of the medium A are increased. From the outlet of the compressor28, the medium A flows to a second heat exchanger30, within which the medium A is cooled. The cooled, compressed medium A output from the second heat exchanger30may then be provided to a condenser32and to a water extractor34in series, to condense and to remove the moisture therefrom, respectively.

From the water extractor34, the warm, dry medium A is provided to an inlet of a turbine36. A turbine, such as turbine36for example, is a mechanical device that expands a medium and extracts work therefrom (also referred to as extracting energy). Within the turbine36, the medium A is expanded, and work is extracted therefrom which results in a cooling and depressurization of the medium A. In an embodiment, the turbine36and the compressor28are operably coupled to one another by a shaft38. In such an embodiment, the turbine36and the compressor28in combination may be referred to as a compression device, such as an air cycle machine.

The further cooled, reduced pressure medium A output from the turbine36may then be provided as a secondary flow to the condenser32. As the secondary flow, the medium A is reheated prior to being delivered to one or more loads24of the aircraft, such as the cabin or cockpit for example. It should be understood that the ECS20illustrated and described herein is intended as an example only and that an ECS20having any suitable configuration is within the scope of the disclosure. Further, an ECS20configured to receive a plurality of mediums and deliver a conditioned form of one or more of those mediums to a load is also contemplated herein.

Because the size and weight of each component of an aircraft is of particular importance, there exists a need to optimize the efficiency of each of the components of the environmental control system20. In an embodiment, enhanced cooling and water removal may be achieved by using a secondary fluid system40to cool and reheat the medium A rather than using a partially conditioned flow of the medium A within the condenser32.

With reference now toFIG.2, an example of an environmental control system20operably coupled to a secondary fluid system40is illustrated. The secondary fluid system40may have a closed loop configuration. In an embodiment, the secondary fluid system40is a vapor compression system. However, it should be understood that any suitable secondary fluid system is within the scope of the disclosure. As shown, the secondary fluid system40includes a compressor42, a condenser44or heat rejection heat exchanger, an expansion device46, and an evaporator48or heat absorption heat exchanger arranged to form a closed fluid loop. A secondary fluid R, such as a refrigerant, for example, is configured to flow from the compressor42to the condenser44, expansion device46, and evaporator48in series. In an embodiment, a motor49is operably coupled to the compressor42to produce work that the compressor42uses to compress the secondary fluid R. However, embodiments where the compressor42is driven alternatively or additionally by another mechanism, such as by a turbine for example, are also within the scope of the disclosure.

In the illustrated, non-limiting embodiment, the environmental control system20is thermally coupled to both the condenser44and the evaporator48of the secondary fluid system40. As shown, the evaporator48has a first medium inlet50in fluid communication with an outlet52of the second heat exchanger30via a conduit54and has a secondary fluid inlet56in fluid communication with an outlet58of the expansion device46via a conduit60. The evaporator48similarly has a first medium outlet62connected to a downstream component and a second fluid outlet64, the second fluid outlet64being connected to an inlet66of the compressor42by a conduit68.

The condenser44of the secondary fluid system40has a first medium inlet70in fluid communication with an upstream component, and a first medium outlet72fluidly connected to an inlet74of the turbine36via a conduit76. The condenser44further has a secondary fluid inlet78connected to an outlet80of the compressor42by conduit82, and a secondary fluid outlet84connected to an inlet86of the expansion device46by a conduit88. The skilled artisan will realize that the condenser44(as well as evaporator48) can be any type of heat exchanger that achieves the desired result of heat transfer with respect to the medium A. For example, the condenser44and the evaporator48can be crossflow heat exchangers.

In the illustrated, non-limiting embodiment, a water extractor90is arranged upstream from the condenser44and downstream from the evaporator48relative to the flow of medium A. The configuration of the water extractor90may be substantially identical to the water extractor34illustrated and described with respect toFIG.1, or alternatively, may have another configuration.

During operation of the secondary fluid system40, a two-phase secondary fluid R within the evaporator48is arranged in a heat exchange relationship with the medium A of the environmental control system20. In an embodiment, the evaporator48of the secondary fluid system40is located directly downstream from the second heat exchanger30relative to the flow of the medium A. Accordingly, heat from the medium A is transferred to the secondary fluid R within the evaporator48, such that the substantial entirety of the secondary fluid R at the outlet of the evaporator48is a vapor.

The further cooled medium A is provided from the outlet62of the evaporator48to the water extractor90. Within the water extractor90, any condensed water within the medium A is extracted, resulting in a dry, cool medium A. This dry, cool medium A may then be provided to the inlet70of the condenser44. At the same time, the vaporized secondary fluid R is delivered from the secondary fluid outlet64of the evaporator48to the inlet66of the compressor42through conduit68. Within the compressor42, the secondary fluid R is further heated and pressurized. The hot, vaporized secondary fluid R output from the outlet80of the compressor42is provided to the secondary fluid inlet78of the condenser44via conduit82. Within the condenser44, the secondary fluid R is arranged in a heat exchange relationship with the dry, cool medium A output from the water extractor90. Within the condenser44, heat is transferred from the hot vapor refrigerant to the dry cool medium A, thereby causing the hot vapor refrigerant to cool and at least partially change phase to a liquid. Additionally, any condensed water that is not removed from medium A via the water extractor90may evaporate in the condenser44such that there will not be any free moisture in medium A when it enters the turbine36, which may prevent wear on the turbine36.

The hot liquid secondary fluid R at the outlet84of the condenser44is then provided to inlet86of the expansion device46through conduit88. Within the expansion device46, pressure is removed from the liquid secondary fluid R, causing at least a portion of the secondary fluid R to change state from a higher pressure liquid to a lower pressure vapor without adding heat thereto. In the illustrated, non-limiting embodiment, the secondary fluid R provided at the outlet58of the expansion device46is a liquid and vapor mixture. The expansion device46, the secondary fluid R is returned to the evaporator48to repeat the cycle.

The hot cool medium A provided at the outlet72of the condenser44is delivered to an inlet74of the turbine36of the compression device. Similar to the embodiment previously described with respect toFIG.1, within the turbine36, the medium A is expanded, and work is extracted therefrom which results in a cooling and depressurization of the medium A. This work extracted from the medium A within the turbine36is used to drive the compressor28via the shaft38. The flow of medium A output from the turbine36may then be delivered to one or more loads24of the aircraft, such as the cabin or cockpit for example.

The thermal connection between the environmental control system20and the vapor compression system is configured to function similarly to the condenser32and water extractor34of existing environmental control systems, such as shown inFIG.1. By using the secondary fluid system40to cool the medium A within the evaporator48, the temperature of the medium A at the outlet62of the evaporator48is as close to freezing or 0° C. or 32° F. as is feasible. This cooling of the medium A results in better formation of water condensation, and therefore more effective water removal from the medium A within the water extractor90.