U.S. patent application number 10/141679 was filed with the patent office on 2002-11-14 for reduced bleed vapor compression cycle environmental control system for aircraft.
Invention is credited to Bertuccioli, Luca, Munoz, Jules Ricardo, Radomsky, Roger W. JR..
Application Number | 20020166923 10/141679 |
Document ID | / |
Family ID | 26839357 |
Filed Date | 2002-11-14 |
United States Patent
Application |
20020166923 |
Kind Code |
A1 |
Munoz, Jules Ricardo ; et
al. |
November 14, 2002 |
Reduced bleed vapor compression cycle environmental control system
for aircraft
Abstract
The present invention relates to a reduced bleed vapor
compression cycle environmental control system for an aircraft. The
environmental control system provides conditioned external ram air
to compartments such as the cabin, the flight deck, avionics
compartment, and other equipment compartments, where conditioned
air is needed. The system includes a first compressor for
compressing the external ram air to cabin pressure and an
evaporator for cooling the external ram air to a desired
temperature. The system further includes a low-pressure water
separator for removing moisture from the ram air prior to the
external ram air being delivered to the compartment(s). The ram air
compressor as well as a compressor for a refrigerant loop are
driven by a turbine that expands a minimal amount of bleed air from
an engine.
Inventors: |
Munoz, Jules Ricardo;
(Vernon, CT) ; Bertuccioli, Luca; (Enfield,
CT) ; Radomsky, Roger W. JR.; (Tucson, AZ) |
Correspondence
Address: |
Barry L. Kelmachter
BACHMAN & LaPOINTE, P.C.
Suite 1201
900 Chapel Street
New Haven
CT
06510-2802
US
|
Family ID: |
26839357 |
Appl. No.: |
10/141679 |
Filed: |
May 7, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60289441 |
May 8, 2001 |
|
|
|
Current U.S.
Class: |
244/118.5 |
Current CPC
Class: |
B64D 13/08 20130101;
Y02T 50/56 20130101; Y02T 50/50 20130101; B64D 13/06 20130101; Y02T
50/40 20130101; Y02T 50/44 20130101; B64D 2013/0614 20130101; B64D
2013/0618 20130101 |
Class at
Publication: |
244/118.5 |
International
Class: |
B64D 011/00; B64D
013/00 |
Claims
What is claimed is:
1. An environmental control system for an aircraft comprising:
means for receiving air external to the aircraft; means for
compressing said external air to a desired pressure; and means for
cooling said compressed air to a desired temperature.
2. An environmental control system according to claim 1, wherein
said cooling means comprises a vapor compression cycle loop.
3. An environmental control system according to claim 1, wherein
said vapor compression cycle loop includes evaporation means for
removing heat from said compressed air.
4. An environmental control system according to claim 3, wherein a
refrigerant flows through said loop and heat from said compressed
air is transferred to said refrigerant in said evaporation
means.
5. An environmental control system according to claim 4, wherein
said loop further includes means for compressing said refrigerant
exiting said evaporation means.
6. An environmental control system according to claim 5, further
comprising said external air compression means comprising a first
compressor, said refrigerant compressing means comprising a second
compressor, and means for driving said first and second
compressors.
7. An environmental control system according to claim 6, wherein
said driving means comprises a turbine and means for supplying
engine bleed air to said turbine.
8. An environmental control system according to claim 7, further
comprising said first and second compressors and said turbine being
located on a single shaft.
9. An environmental control system according to claim 5, wherein
said loop further includes means for removing heat from said
compressed refrigerant.
10. An environmental control system according to claim 9, wherein
additional external air is supplied to said loop and said heat
removing means comprises a condenser for receiving said compressed
refrigerant from said refrigerant compressing means and for
transferring heat from said refrigerant to said additional external
air.
11. An environmental control system according to claim 10, wherein
said loop further includes means for reducing pressure in said
refrigerant exiting said heat removing means.
12. An environmental control system according to claim 11, wherein
said pressure reducing means comprises an expansion valve.
13. An environmental control system according to claim 1, further
comprising means for delivering said cooled air to a cabin onboard
said aircraft.
14. An environmental control system according to claim 13, further
comprising means for removing moisture from said external air prior
to delivering said cooled air to said cabin.
15. An environmental control system according to claim 14, wherein
said moisture removing means comprises a water separator.
16. A method for delivering cooled air at a desired pressure to a
compartment on an aircraft comprising the steps of: providing an
air compressor; inputting air external to said aircraft into said
air compressor and compressing said external air; cooling said
external air after said external air exits said air compressor; and
delivering said cooled external air to said compartment.
17. A method according to claim 16, further comprising removing
moisture from said cooled external air prior to delivering said
cooled external air to said compartment.
18. A method according to claim 16, wherein said cooling step
comprises providing a refrigerant loop having an evaporator through
which a refrigerant flows and passing said compressed external air
through said evaporator and transferring heat from said compressed
external air to said refrigerant.
19. A method according to claim 18, further comprising compressing
said refrigerant exiting said evaporator using a refrigerant
compressor.
20. A method according to claim 19, further comprising providing a
turbine, bleeding air from an engine to drive said turbine, and
driving both said air compressor and said refrigerant compressor
using said turbine.
21. A method according to claim 19, further comprising providing
said loop with heat removal means, supplying additional external
air to said heat removal means, and transferring heat from said
compressed refrigerant to said additional external air by passing
said compressed refrigerant through said heat removal means.
22. A method according to claim 21, further comprising reducing
pressure of said refrigerant exiting said heat removal means and
passing said refrigerant at said reduced pressure to said
evaporator.
23. A method according to claim 16, wherein said delivering step
comprises delivering said cooled external air to a cabin onboard
said aircraft.
Description
CROSS REFERENCE TO RELATED APPLICATION(S)
[0001] This application claims the benefit of U.S. Provisional
Patent Application No. 60/289,441, filed May 8, 2001, entitled
REDUCED BLEED VAPOR COMPRESSION CYCLE ENVIRONMENTAL CONTROL SYSTEM
FOR AIRCRAFT.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to an environmental control
system for an aircraft.
[0003] The purpose of an environmental control system (ECS) is to
supply cooled pressurized air to the cabin and the flight deck.
This is typically accomplished by the use of an air cycle machine
(ACM). FIG. 1 shows a schematic representation of a typical
environmental control system 10 for an aircraft. Depending upon the
mission point, bleed air from the engine 12 is removed from either
the mid- or high-pressure stages of the high compressor 14. The
bleed air is first cooled by ram air in a primary heat exchanger
16. The bleed air is then further compressed in the compressor
section 18 of the air cycle machine. Additional cooling of the
bleed air is performed in a secondary heat exchanger 20 using ram
air as the coolant. The bleed air is then expanded to the desired
pressure across the turbine section 22 of the air cycle machine.
The expansion process produces the necessary work required to drive
the compressor 18 and significantly drops the temperature of the
bleed air. The cooled bleed air is then mixed with cabin
recirculation air to maintain the temperature of the air entering
the cabin at a given level.
[0004] The use of an air cycle machine for an environmental control
system is a parasitic loss for the engine because it requires the
extraction of engine bleed air to operate. A typical environmental
control system can require as much as 5% of the core flow from the
engine. Reducing the amount of engine bleed air necessary to
operate an environmental control system would result in an
improvement in engine specific fuel consumption.
SUMMARY OF THE INVENTION
[0005] Accordingly, it is an object of the present invention to
provide an environmental control system for an aircraft which
reduces engine bleed air requirements.
[0006] It is a further object of the present invention to provide
an environmental control system as above which helps reduce fuel
consumption.
[0007] The foregoing objects are attained by the environmental
control system of the present invention.
[0008] In accordance with the present invention, an environmental
control system for an aircraft is provided. The environmental
control system provides conditioned ram air to areas, such as the
cabin, the flight deck and/or another compartment onboard the
aircraft, where conditioned air is needed. The system broadly
comprises means for receiving air external to the aircraft, means
for compressing the external air to a desired pressure, such as
cabin pressure, and means for cooling the compressed external air
to a desired temperature. The cooling means includes a refrigerant
loop. The system further includes a low-pressure water separator
for removing moisture from the ram air prior to the cooled external
air being delivered to the desired location. An external air
compressor as well as a compressor for the refrigerant loop are
driven by a turbine that expands a minimal amount of bleed air from
a main engine compressor.
[0009] A method for delivering cooled air at a desired pressure to
a compartment on an aircraft broadly comprises the steps of
providing an air compressor, inputting air external to the aircraft
into the air compressor and compressing said external air, cooling
the external air exiting the air compressor, and delivering the
cooled external air to the compartment.
[0010] Other details of the environmental control system of the
present invention, as well as other objects and advantages
attendant thereto, are set forth in the following detailed
description and the accompanying drawings, wherein like reference
numerals depict like elements.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a schematic representation of a prior art air
cycle environmental control system; and
[0012] FIG. 2 is a schematic representation of a reduced bleed
vapor compression environmental control system in accordance with
the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
[0013] The system 40 of the present invention involves the use of a
vapor compression cycle in place of the conventional air cycle
machine. Referring now to FIG. 2, in the inventive system 40,
instead of using engine bleed air for the environmental control
system, external ram air is compressed to the necessary cabin
pressure by using an air compressor 42. Following compression in
the compressor 42, the ram air is cooled to a desired temperature,
such as cabin temperature, in an evaporator 44 which forms part of
a vapor compression cycle. A low-pressure water separator 46 is
located downstream of the evaporator 44 to remove moisture from the
air prior to entering a compartment 48, such as a cabin, a flight
deck, avionics compartment, and/or other equipment compartment.
[0014] The system 40 further has a refrigerant loop 50 which
includes a refrigerant compressor 52, a condenser 54, the
evaporator 44, and an expansion valve 56. The refrigerant or
working fluid in the loop 50 may comprise any suitable refrigerant
known in the art.
[0015] The working fluid, the refrigerant, undergoes a
thermodynamic cycle in the loop 50. Heat from the external air
entering the compartment(s) 48 is transferred to the refrigerant in
the evaporator 44, where the refrigerant's temperature and pressure
are low. The evaporator 44 may comprise any suitable evaporator
known in the art which enables heat from the compressed external
air to be transferred to the refrigerant. Work is then done on the
refrigerant exiting the evaporator 44 in the compressor 52 which
reuses the pressure of the refrigerant. Heat is transferred from
the refrigerant in the condenser 54, where the refrigerant's
temperature and pressure are high. As can be seen from FIG. 2,
additional external ram air is supplied to the condenser 54 to
remove heat from the refrigerant as the refrigerant passes through
the condenser 54. The condenser 54 may comprise any suitable
condenser known in the art which enables heat from the refrigerant
to be transferred to the additional external air. In the
refrigerant loop 50 in the system of the present invention, a
pressure drop occurs as the refrigerant flows through the pressure
reducing means such as expansion valve 56.
[0016] As can be seen from FIG. 2, the ram air compressor 42 and
the refrigerant compressor 52 are each driven by a turbine 62 which
is connected to them by a means 60 of mechanical transmission or a
shaft. The turbine 62 receives and expands a minimal amount of
bleed air from a main engine compressor of an engine 64, thus
providing the work necessary to drive the compressors 42 and
52.
[0017] In the system of the present invention, any suitable means
known in the art may be used to supply the external ram air to the
compressor 42 and to the condenser 54. For example, inlets may be
provided on exterior surfaces of the aircraft to capture the
external air. Alternatively, air scoops may be utilized.
[0018] Initial calculations have shown that roughly 25% of the
current engine bleed air amounts would be required to drive
compressors 42 and 52. This significant reduction in engine bleed
leads to a decrease in the specific fuel consumption of the engine.
The resulting fuel burn savings offsets the slightly higher weight
of the vapor compression cycle compared to that of a conventional
air cycle environmental control system, when calculated over a
ninety minute mission. These calculations have taken into account
the additional thrust necessary to overcome the momentum drag
generated by a ram air scoop for the cabin air. Lengthier missions
will likely result in a decrease in take-off gross weight, i.e. the
weight of fuel saved is greater than the additional weight of the
environmental control system.
[0019] The advantage of the system of the present invention is the
large fuel savings with the resulting operating cost reductions.
Furthermore, additional engine weight and cost reductions can be
achieved by eliminating one of the bleed ports typically dedicated
to the environmental control system.
[0020] It is apparent that there has been provided in accordance
with the present invention a reduced bleed vapor compression cycle
environmental control system for aircraft which fully satisfies the
objects, means, and advantages set forth hereinbefore. While the
present invention has been described in the context of specific
embodiments thereof, other alternatives, modifications, and
variations will become apparent to those skilled in the art having
read the foregoing description. Therefore, it is intended to
embrace those alternatives, modifications, and variations which
fall within the broad scope of the appended claims.
* * * * *