U.S. patent application number 13/409955 was filed with the patent office on 2012-07-12 for system and method for cooling at least one heat producing device in an aircraft.
This patent application is currently assigned to AIRBUS OPERATIONS GMBH. Invention is credited to Jean BLENNER, Jan DITTMAR, Anja ERDLE, Georg MUEHTHALER, Sebastian ROERING, Cherif TERZI.
Application Number | 20120175080 13/409955 |
Document ID | / |
Family ID | 43536034 |
Filed Date | 2012-07-12 |
United States Patent
Application |
20120175080 |
Kind Code |
A1 |
MUEHTHALER; Georg ; et
al. |
July 12, 2012 |
SYSTEM AND METHOD FOR COOLING AT LEAST ONE HEAT PRODUCING DEVICE IN
AN AIRCRAFT
Abstract
A system is provided for cooling at least one heat producing
device in an aircraft that includes, but is not limited to at least
one coolant circuit. A coolant absorbs heat from the heat producing
device and dissipates heat, by way of a heat dissipation device, to
the surroundings of the aircraft. A temperature spreading device
reduces the temperature of the coolant in a feed line of the
coolant circuit and increases the heat dissipation temperature of
the heat dissipation device relative to the temperature of the
coolant in a return line of the coolant circuit. In this manner ram
air ducts that are commonly used in the state of the art or systems
that consume pre-cooled air can be avoided, which in particular
when the aircraft is situated on the ground on hot days can render
avionics cooling or the like difficult.
Inventors: |
MUEHTHALER; Georg; (Hamburg,
DE) ; ERDLE; Anja; (Hamburg, DE) ; DITTMAR;
Jan; (Buxtehude, DE) ; ROERING; Sebastian;
(Hamburg, DE) ; TERZI; Cherif; (Hamburg, DE)
; BLENNER; Jean; (Strasbourg, FR) |
Assignee: |
AIRBUS OPERATIONS GMBH
Hamburg
DE
|
Family ID: |
43536034 |
Appl. No.: |
13/409955 |
Filed: |
March 1, 2012 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
PCT/EP2010/062734 |
Aug 31, 2010 |
|
|
|
13409955 |
|
|
|
|
61239244 |
Sep 2, 2009 |
|
|
|
Current U.S.
Class: |
165/96 ;
165/104.11 |
Current CPC
Class: |
B64D 13/08 20130101;
B64D 2013/0614 20130101; Y02T 50/50 20130101; Y02T 50/56 20130101;
F25B 29/003 20130101 |
Class at
Publication: |
165/96 ;
165/104.11 |
International
Class: |
F28D 15/00 20060101
F28D015/00; F28F 27/00 20060101 F28F027/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 2, 2009 |
DE |
10 2009 039 814.7 |
Claims
1. A system for cooling at least one heat producing device in an
aircraft, comprising: at least one coolant circuit configured to
receive a coolant in order to absorb heat from the heat producing
device, the coolant circuit comprising: a feed line arranged
upstream of the heat producing device; and a return line arranged
downstream of the heat producing device; a heat dissipation device
that is configured to thermally communicate with the return line
and dissipate heat from the coolant circuit; and a temperature
spreading device configured to reduce a temperature of the coolant
in the feed line and increase a heat dissipation temperature of the
heat dissipation device relative to the temperature of the coolant
in the return line of the coolant circuit.
2. The system of claim 1, further comprising a skin-section heat
exchanger arranged on an outer skin of the aircraft with flow ducts
as the heat dissipation device that thermally connects the flow
ducts to the outer skin.
3. The system of claim 2, further comprising an air duct that is
delimited by the skin-section heat exchanger towards the outside of
the aircraft with heat dissipation elements that extend into the
air duct, and around which the heat dissipation elements are
configured to flow.
4. The system of claim 3, further comprising at least one closing
element configured to open or close at least one opening of the air
duct.
5. The system of claim 1, wherein the coolant circuit is an open
circulation system.
6. The system of claim 1, further comprising at least one conveying
device configured to convey the coolant in the coolant circuit.
7. The system of claim 1, wherein the temperature spreading device
comprises a cooling medium circuit with a condenser and an
evaporator.
8. The system of claim 7, wherein the condenser is arranged at the
return line of the coolant circuit.
9. The system of claim 7, wherein the evaporator is arranged at the
feed line or at the return line of the coolant circuit.
10. The system of claim 9, wherein the heat dissipation device is
implemented by the condenser that is configured to be cooled with
air from an additional air source, and wherein the additional air
source provides air.
11. The system of claim 10, wherein the condenser is connected to a
heat exchanger that is configured to be cooled by air.
12. The system of claim 1, further comprising two coolant circuits
comprising feed lines that are thermally interconnected with a heat
exchanger.
13. The system of claim 12, wherein the feed line and the return
line of the two coolant circuits are configured to communicate in a
switchable manner by way of valves.
14. A method for cooling at least one system for cooling at least
one heat producing device in an aircraft, comprising: absorbing
heat from the heat producing device with a coolant flowing into a
return line of a coolant circuit; increasing a temperature of the
coolant in the return line; dissipating heat from the coolant whose
temperature has been increased with a dissipation device; and
reducing the temperature of the coolant flowing into a feed line of
the coolant circuit.
15. An aircraft, comprising: at least one space; at least one
coolant circuit within the at least one space that is configured to
receive a coolant in order to absorb heat from the heat producing
device, the coolant circuit comprising: a feed line arranged
upstream of the heat producing device; and a return line arranged
downstream of the heat producing device; a heat dissipation device
within the at least one space that is configured to thermally
communicate with the return line and dissipate heat from the
coolant circuit; and a temperature spreading device configured to
reduce a temperature of the coolant in the feed line and increase a
heat dissipation temperature of the heat dissipation device
relative to the temperature of the coolant in the return line of
the coolant circuit.
16. The aircraft of claim 15, further comprising a skin-section
heat exchanger arranged on an outer skin of the aircraft with flow
ducts as the heat dissipation device that thermally connects the
flow ducts to the outer skin.
17. The aircraft of claim 16, further comprising an air duct that
is delimited by the skin-section heat exchanger towards the outside
of the aircraft with heat dissipation elements that extend into the
air duct, and around which the heat dissipation elements are
configured to flow.
18. The aircraft of claim 17, further comprising at least one
closing element configured to open or close at least one opening of
the air duct.
19. The aircraft of claim 15, wherein the coolant circuit is an
open circulation system.
20. The aircraft of claim 15, further comprising at least one
conveying device configured to convey the coolant in the coolant
circuit.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of International
Application No. PCT/EP2010/062734, filed Aug. 31, 2010, which was
published under PCT Article 21(2) and claims priority to U.S.
Provisional Patent Application No. 61/239,244, filed Sep. 2, 2009
and also claims priority to German Patent Application No. 10 2009
039 814.7, filed Sep. 2, 2009, the contents of which applications
are incorporated herein by reference.
TECHNICAL FIELD
[0002] The technical field relates to a system for cooling at least
one heat producing device in an aircraft and to a method for
cooling at least one heat producing device. The technical field
also relates to the use of a system for cooling at least one heat
producing device in an aircraft and to an aircraft comprising at
least one heat producing device and at least one system for cooling
the heat producing device.
BACKGROUND
[0003] In larger aircraft of a modern design, increasingly a
multitude of devices are integrated which during normal operation
of the aircraft produce a considerable amount of heat which must
safely and reliably be removed from the aircraft and dissipated,
for example to the environment. For example, modern commercial
aircraft comprise a multitude of different arithmetic units or
other (power) electronics units, which are generally referred to as
"avionics" and which are accommodated in an avionics compartment.
In the state of the art, avionics compartments in aircraft are
cooled by means of various systems. Systems are known in which a
coolant by way of a coolant circuit absorbs heat from the avionics
compartment and dissipates said heat to the environment by means of
a skin-section heat exchanger. However, in this arrangement, the
situation when the aircraft is located on the ground on hot days is
important, because the temperature difference between the
skin-section heat exchanger and the environment may be insufficient
to carry out adequate heat dissipation.
[0004] Furthermore, it is known, at least in flight, to cool
components in the avionics compartment by blowing in air from the
aircraft cabin. Air from the so-called "triangular region"
underneath the cabin floor and near the fuselage wall may be
removed and, after absorbing heat from the avionics devices, leaves
the avionics compartment in a heated state. However, this requires
that the air conditioning system of the aircraft is already
operative and, in particular, during stops on the ground on hot
days, the cabin has been cooled down to a predetermined temperature
level. Accordingly, it may be required, during operation of an
aircraft on a hot day, to operate the air conditioning system
before the avionics devices can be switched on.
[0005] Furthermore, it is known for outside air to be used in order
to dissipate heat from the interior of an aircraft to its
environment. To this effect, by way of a so-called ram air duct,
air that flows past the aircraft in flight is guided into the
interior of the aircraft, is fed by way of a heat exchanger that
thermally communicates with the coolant to be cooled, and is
discharged to the aircraft environment by way of an outlet opening.
In this process, the air flowing through the ram air duct absorbs
heat to be dissipated. This principle is, for example, already used
in aircraft air conditioning systems in order to cool hot
compressed air that is later to flow into the aircraft cabin.
Furthermore, this principle is used in cooling systems, as
described for example in DE 4340317. The air flowing through the
ram air duct may, however, noticeably increase the aerodynamic
resistance of the aircraft in flight. On the ground, the ram air
can be conveyed through the ram air duct by means of a fan.
[0006] It may thus be considered at least one object to propose a
cooling system for cooling heat producing devices in an aircraft,
which cooling system independently of an ambient temperature and
independently of an air conditioning system makes possible reliable
cooling of the heat producing devices. Likewise, it may be
considered at least one object to propose such a cooling system
that is associated with as little complexity as possible, with the
lowest possible energy requirement, the lightest possible weight,
which cooling system in particular does not generate any additional
aerodynamic resistance. In addition, other objects, desirable
features, and characteristics will become apparent from the
subsequent summary and detailed description, and the appended
claims, taken in conjunction with the accompanying drawings and
this background.
SUMMARY
[0007] A system is provided for cooling at least one heat producing
device in an aircraft, comprising at least one coolant circuit
through which coolant flows in order to absorb heat from the heat
producing device. The coolant circuit comprises a feed line
arranged upstream of the heat producing device, and a return line
arranged downstream of the heat producing device. The system is a
heat dissipation device that thermally communicates with the return
line of the coolant circuit provided for dissipating heat from the
coolant circuit, in that a temperature spreading device reduces the
temperature of the coolant in the feed line of the coolant circuit
and increases a heat dissipation temperature of the heat
dissipation device relative to the temperature of the coolant in
the return line of the coolant circuit.
[0008] The type of heat dissipation device does not limit the
invention. Instead, numerous types of heat dissipation devices are
to be considered as being suitable, by means of which heat can be
dissipated to an environment. The use of heat transfer devices
suggests itself, which heat transfer devices implement direct,
indirect (recuperative), and/or semi-direct heat transfer. The
coolant can be of a liquid or gaseous nature. Any type of commonly
used coolant or special coolant can be used. The invention is not
limited to the type of coolant.
[0009] Thus by means of the temperature spreading device the
coolant is cooled down to a suitable temperature so that a distinct
and adequate temperature difference to corresponding heat transfer
means (cooling elements, heat exchangers and the like) on the heat
producing devices is produced in order to in an efficient manner
absorb heat from the heat producing devices. At the same time, by
means of the temperature spreading device, the heat dissipation
temperature of a heat dissipation device is significantly increased
relative to the temperature of the coolant in the return line. This
means that even when the aircraft is situated on the ground on hot
days in the sun an adequate temperature difference between the heat
dissipation device and the environment of the aircraft can be
ensured.
[0010] This provides a further technical effect in that it is not
necessary to have already started up an air conditioning system of
the aircraft in order to be able to provide adequately cool air for
cooling the heat producing devices. Instead, it is imaginable to
start up the temperature spreading device already shortly before
starting up the heat producing devices so that in a relatively
timely manner adequate cooling of the heat producing devices can be
ensured even in the case of extreme temperatures within the
aircraft. By means of the significant increase in temperature
relative to the temperature of the coolant in the return line of
the coolant circuit any type of heat dissipation device, for
example a heat exchanger or the like, can dissipate the heat
absorbed by the coolant to the environment even in the case of
extreme ambient temperatures.
[0011] The embodiments are not limited to the use of a single
design of a temperature spreading device; instead, any equipment,
devices, and systems can be used that are able to spread a
temperature level between two coolant lines. Accordingly,
compression cooling machines, absorption cooling machines,
diffusion absorption cooling machines, adsorption cooling machines,
cooling machines based on the Joule-Thomson effect,
thermo-electrical cooling generators (Peltier elements) and the
like are imaginable. In addition, heat sinks or heat sources are
imaginable in order to increase or decrease the temperature in a
coolant line.
[0012] The design of the system is not complex, involves low-cost
technically mature components, and operable without active blowing
of cooling air or the like from the aircraft to the outside.
[0013] According to another embodiment of the system, the heat
dissipation device is designed as a skin-section heat exchanger.
The skin-section heat exchanger can in particular in flight ensure
adequate heat transport to the environment. In order to improve the
cooling performance with the aircraft situated on the ground, the
skin-section heat exchanger can extend into an air duct pointing
towards the aircraft interior, which air duct comprises at least
one conveying device for conveying air from the environment or for
conveying ram air. The extension of the skin-section heat exchanger
into the air duct means that the skin-section heat exchanger can
not only dissipate heat on the outside of the aircraft, but also
comprises lamellae, ribs or other air-permeable structures towards
the interior of the aircraft, which structures make it possible to
dissipate heat to the ambient air. With the aircraft stationary on
the ground, an air flow through the air duct can be enforced by
operating the conveying device.
[0014] In another embodiment of the system, on openings that are
directed towards the surroundings the air duct comprises closing
elements, which during adequate flight speed of the aircraft can be
closed in order to eliminate the additional aerodynamic resistance.
The closing elements may, for example, be designed in the form of
flaps or rotary-closure screens. The drive is to be implemented by
electric, pneumatic, or hydraulic actuators that are customary in
this special field.
[0015] In another embodiment of the system, the coolant circuit is
an open circulation system. This provides an advantage in that air
can be used as a coolant. Since a certain air volume flow needs to
be removed anyway from the cabin of the aircraft to the
environment, at least part of this can be used as coolant for the
system.
[0016] Furthermore, in another embodiment, the temperature
spreading device comprises a first coolant medium circuit with a
condenser and an evaporator. In this way, by means of mature
technology, in a mechanically simple manner and economical manner
adequate temperature spreading and consequently particularly
efficient cooling can be achieved by means of the system according
to the invention.
[0017] According to another embodiment of the system, the condenser
can be cooled with air from an additional air source. The air
source is situated in the interior of the aircraft and/or is
implemented with the use of ambient air and/or bleed air. In this
manner, still further improved temperature spreading is achieved.
This suggests itself in those cases where air is used as a coolant,
and in particular, where the coolant circuit is open.
[0018] In another embodiment, the condenser is arranged at the
return line of the coolant circuit. In this manner, at the same
time, the temperature reduction that can be achieved by the
evaporator is improved and consequently the overall efficiency of
the system is improved.
[0019] At the same time, the evaporator too can be arranged at the
return line of the coolant circuit. In this case, however, the
condenser is not to be arranged at the feed line of the coolant
circuit, but instead may, for example, be directly connected to the
heat dissipation device or to some other heat dissipating
element.
[0020] According to another embodiment of the system according, the
condenser can be connected to a heat exchanger that is subjected to
air from an air source. The air source is located in the interior
of the aircraft, and/or is implemented by ambient air.
Consequently, in this embodiment, too, the heat of the condenser
can be dissipated by means of the heat exchanger to the
through-flowing air from the air source.
[0021] Furthermore, in another embodiment of the system according,
the temperature spreading device may comprise a first heat
exchanger for cooling coolant from the return line of the coolant
circuit with air from an air source. The air source is situated in
the interior of the aircraft, and/or is implemented by ambient air.
In this manner, at least in the case where the air conditioning
system of the aircraft is already in operation, or in the case of
adequately low ambient temperatures, reliable operation of the
system can be achieved. The temperature spreading device should
then in addition comprise further measures at least for cooling the
coolant in the feed line.
[0022] A method is provided for cooling at least one heat producing
device, by the use of a system for cooling at least one heat
producing device in an aircraft, and by an aircraft comprising at
least one heat producing device and at least one system for cooling
a heat producing device in an aircraft.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Further characteristics, advantages, and application options
of the present invention are disclosed in the following description
of the exemplary embodiments and of the Figs. All the described
and/or illustrated characteristics per se and in any combination
form the subject of the embodiments, even irrespective of their
composition in the individual claims or their interrelationships.
Furthermore, identical or similar components in the Figs have the
same reference characters.
[0024] FIG. 1 shows a diagrammatic view of a first exemplary
embodiment of the system.
[0025] FIG. 2 shows a diagrammatic view of a second exemplary
embodiment of the system.
[0026] FIG. 3 shows a diagrammatic view of a third exemplary
embodiment of the system.
[0027] FIG. 4 shows a diagrammatic view of a fourth exemplary
embodiment of the system.
[0028] FIG. 5 shows a diagrammatic view of a fifth exemplary
embodiment of the system.
[0029] FIG. 6 shows a diagrammatic view of a sixth exemplary
embodiment of the system.
[0030] FIG. 7 shows a diagrammatic view of a skin-section heat
exchanger according to an embodiment.
[0031] FIG. 8 shows a diagrammatic view of a method according to an
embodiment.
[0032] FIG. 9 shows an aircraft comprising at least one system
according to an embodiment.
DETAILED DESCRIPTION
[0033] In FIG. 1, a first exemplary embodiment of a system 2 is
shown for cooling at least one heat producing device 4 in an
aircraft. As an example, a space 6 is shown in which the heat
producing devices 4 are accommodated. The design of this space 6,
which can, for example, be an avionics compartment, does not form
part of the embodiments and accordingly is not described in detail.
However, it should be pointed out that the heat producing devices 4
comprise suitable means with which heat can be dissipated to a
coolant. These means can be of any design, for example heat
exchangers, cooling elements or cooling fins around which air or
the like flows.
[0034] The system 2 further comprises a heat dissipation device 8,
which with a feed line 10 and a return line 12 of the space 6 or
the heat producing device 4 forms a closed circulation system. In
this circulation system, a coolant circulates that flows from the
feed line 10 to the heat producing devices 4 where it absorbs heat.
The coolant subsequently flows into the return line 12 to the heat
dissipation device 8 where it dissipates heat to the environment of
the aircraft, and subsequently again flows to the feed line 10
where it is again available for heat absorption.
[0035] Efficient heat dissipation by the heat dissipation device 8
to the environment, and particularly efficient heat absorption from
a heat producing device 4 by the coolant from the feed line 10 can
be achieved only in those cases where there is a corresponding
temperature gradient to the environment or to the coolant. In
particular, at high temperatures it can be difficult or entirely
impossible to achieve a correspondingly high heat dissipation
temperature in the heat dissipation device 8, which makes possible
a heat flow to the environment in the first place. Likewise without
further equipment the temperature of the coolant in the feed line
10 would be so high that there is no adequate temperature
difference for cooling the heat producing devices 4, and in turn as
a result of this a very high volume flow of the coolant becomes
necessary. If the temperature of the environment is too high, even
the highest coolant flow may not be sufficient to dissipate the
heat.
[0036] For this reason, the system 2 comprises a temperature
spreading device 14, which as an example is designed as a cooling
medium circuit with a condenser 16, a flow control valve 18, an
evaporator 20, and a compressor 22. This cooling medium circuit,
which is also referred to as a cold-vapor cooling machine, is able
to increase the temperature of the coolant from the return line 12
by means of the condenser 16, and to lower said temperature by
means of the evaporator 20. This means that the coolant from the
return line 12, which has already absorbed heat, is heated still
further so that the heat dissipation temperature in the heat
dissipation device 8 is clearly increased. This has the effect that
the temperature gradient to the environment is adequate even on hot
days, thus allowing efficient dissipation of heat. Likewise, the
coolant flowing to the feed line 10 is cooled to a significantly
lower temperature by the evaporator 20 so that, as a result,
efficient absorption of heat from the heat producing device 4 can
take place. If it were to become necessary, for example, due to a
low ambient temperature, to increase to a lesser extent the
temperature of the coolant flowing into the return line 12, in
order to reduce heating of the coolant, a bypass 24 can be arranged
on the condenser 16 so that at least part of the coolant flowing
into the return line 12 can flow directly to the heat dissipation
device 8.
[0037] FIG. 2 shows a modification in the form of a system 26,
where here again the temperature spreading device 14 is designed as
a cooling medium circuit; however, in this embodiment the
overarching coolant circuit is not closed. This implicitly means
that in particular air is used as a coolant, which air is taken
from an air source and is again dissipated to the environment of
the aircraft.
[0038] In addition, the system 26 comprises an optional further air
source 28, which introduces air into the return line 12 of the
coolant circuit. As a result, the temperature of the coolant from
the return line 12 is reduced before said coolant reaches the
condenser 16. An optional bypass 24, shown in a dashed line in the
illustration, serves to maintain the volume flow balance, and
possibly for the exclusive use of air from the air source 28 for
cooling the condenser 16, should this air be cooler than the
temperature in the return line 12 of the coolant circuit.
[0039] If the aircraft is stationed on the ground on a hot day, it
is not expected that ambient air automatically enters the aircraft
in order to be used in the system 26. The system 26 thus comprises,
for example, two conveying devices 30 and 32 by means of which
fresh air from the surroundings of the aircraft is channeled to the
evaporator 20 in the direction of the feed line 10 and is then
conveyed from the aircraft to the outside. In this arrangement, the
conveying devices 30 and 32 are located on suitable air openings 34
and 36, which, for example, in flight can be closed by means of
closing elements 38 and 40, and on the ground, can be opened
again.
[0040] FIG. 3 shows a further embodiment of the system 42, in which
system 42 a liquid coolant, conveyed by means of a conveying device
62, may be used in a closed circulation system. The closed
circulation system comprises a heat dissipation device 44 which,
for example, implemented by combining a heat exchanger 46 and a fan
48 in a ram air duct 50.
[0041] In order to achieve an efficient spread of the temperature
level between the heat dissipation device 44 and the feed line 10 a
temperature spreading device 52 in the form of a cooling medium
circuit is used, with the latter comprising an evaporator 54, a
compressor 56, a condenser 58, and a flow control valve 60.
However, in the figure, as an example the evaporator 54 is arranged
between the feed line 10 and the return line 12 so that
consequently the temperature of the coolant flowing from the return
line 12 to the feed line 10 is reduced. Since already upstream of
the evaporator 54 a heat dissipation device 44 can dissipate heat
from the return line 12, with the use of the cooling medium circuit
52, the temperature in the feed line 10 can be further reduced to a
significant extent.
[0042] Furthermore, the condenser 58 is cooled in a ram air duct or
from an additional air source 28, for example, with the use of
extraction air that also, for example, originates from the avionics
compartment, from the cockpit, or from the cabin. As an
alternative, the alternative air source 28 can be implemented by
means of an inlet valve for ambient air on the aircraft fuselage,
or by means of bleed air from one or several engines 130.
[0043] FIG. 4 shows a further embodiment of the system 64, where in
the previously mentioned, the coolant circuit can be constructed to
be either closed or open. A conveying device 66 conveys the coolant
from the return line 12 to the feed line 10, where the coolant
flows through an evaporator 68 of a temperature spreading device 70
that is implemented as a cooling medium circuit that also comprises
a compressor 72, a condenser 74, and a flow control valve 76. As a
result, the temperature of the coolant in the feed line 10 is
significantly reduced, which results in improved heat absorption of
the heat from the heat producing devices 4. The condenser 74 of the
cooling medium circuit 70 is cooled by means of a secondary cooling
device 78, where the latter may, for example, comprise a conveying
device 80, a heat exchanger 82, and a fan 84 in a ram air duct
86.
[0044] Such an arrangement is associated with a particular
advantage in that the temperature spreading device 70 can be
accommodated and operated in a pressurized region of the aircraft
fuselage. In theory, a temperature spreading device, for example
the temperature spreading device 52 of FIG. 3, may partially or
completely be accommodated in a non-pressurized region of the
aircraft, which may simplify the installation when compared to
integration of the temperature spreading device 52 in the
non-pressurized region. However, this may be unfavorable for
maintenance purposes, because the cooling medium circuit would have
to be interrupted for maintenance purposes.
[0045] If the system 64 is operated as an open circuit, then the
two conveying devices 30 and 32 shown in FIG. 2 may be arranged
upstream of the feed line 10 and downstream of the return line 12.
In this case, it would also be possible to use air from the
environment or from the interior of the aircraft as a coolant. If
the coolant circuit is designed to be closed, any suitable coolant
can be used.
[0046] It is of course possible to use not only one single system
2, 26, 42 or 64 in an aircraft; for reasons associated with
redundancy, multiplication is also imaginable. For this reason,
FIG. 5 as an example, shows a combination of two systems 42
according to FIG. 3, albeit without the ram air duct 50, the heat
exchanger 46 arranged therein, and the fan 48. This embodiment of a
system 88 thus comprises two coolant circuits, each being cooled by
a temperature spreading device 90 implemented as a cooling medium
circuit. The two coolant circuits are thermally interconnected by
valves 92 and 94 as well as/or by a heat exchanger 96. It should be
pointed out that the illustration is symmetrical, i.e., the upper
coolant circuit in the drawing plane is shown in a mirror-inverted
manner relative to the lower coolant circuit.
[0047] If, for example, one of the two temperature spreading
devices 90 were to fail, the return lines 12 of the two coolant
circuits may be pneumatically interconnected by means of the valve
92, and the feed lines 10 of the two coolant circuits may be
pneumatically interconnected by means of a valve 94. As an
alternative or in addition to this, it is also possible for heat to
be transferred by way of the heat exchanger 96 from one coolant
circuit to the other coolant circuit. This ensures that, for
example, two spaces 6 with several heat producing devices 4 in an
aircraft, which spaces are positioned at locations that are
situated apart from each other, can be cooled adequately, also on
the ground, also if one of the temperature spreading devices 90
were to fail.
[0048] FIG. 6 diagrammatically shows a generalized embodiment of
the system 98, which embodiment can relate to all the
above-described embodiments. A temperature spreading device 100,
which can be implemented in any desired manner, is integrated in a
coolant circuit that is connected to a special form of a heat
dissipation device 8 in the form of a skin-section heat exchanger
102. The skin-section heat exchanger 102 comprises not only flow
ducts 103 that for convective heat dissipation to the environment
are thermally connected to an outer skin area 104, through which
flow ducts 103 coolant or cooling media flow, but also a ram air
duct 108 as illustrated in FIG. 7. The ram air duct 108, which
comprises a first opening 110 and a second opening 112, is located
between the outer skin 104 of the skin-section heat exchanger 102
and the aircraft interior, which in the diagram is designated by
reference character 106. Through the first opening 110 air can flow
into the ram air duct 108, and through the opening 112 said air can
leave said ram air duct 108 again. Heat dissipation elements 114,
which as an example are designed as cooling ribs, extend from the
skin-section heat exchanger 102 to the ram air duct 108, around
which heat dissipation elements 114 air flowing through the duct
108 flows. In this manner, the efficiency of heat transfer to the
environment can be improved.
[0049] To achieve an adequate airflow for absorbing the heat of the
skin-section heat exchanger 102 when the aircraft is situated on
the ground, in addition a fan 116 is arranged in the ram air duct
108. Accordingly, the skin-section heat exchanger 102 is not
limited to heat transfer by convection on the outer skin 104. In
order to reduce the aerodynamic resistance during flight phases
with adequately high flight speed and adequately good heat transfer
through the outer skin 104, the openings 110 and 112 can be closed
by mechanically driven closing elements 118.
[0050] In a method as shown in FIG. 8, at first heat from heat
producing devices is absorbed 120 by means of a coolant flowing
into a return line of a coolant circuit, and subsequently the
temperature of the coolant in the return line is increased 122. By
means of a heat dissipation device, heat from the coolant whose
temperature has been increased is dissipated 124, and subsequently
the temperature of the coolant flowing into a feed line of the
coolant circuit is reduced 126.
[0051] Finally, FIG. 9 shows an aircraft 128 that is equipped with
at least one system according to the invention for cooling at least
one heat producing device.
[0052] It should be pointed out that "comprising" does not exclude
other elements or steps, and "a" or "one" does not exclude a plural
number. Furthermore, it should be pointed out that characteristics
or steps, which have been described with reference to one of the
above exemplary embodiments, can also be used in combination with
other characteristics or steps of other exemplary embodiments
described above. In addition, while at least one exemplary
embodiment has been presented in the foregoing summary and detailed
description, it should be appreciated that a vast number of
variations exist. It should also be appreciated that the exemplary
embodiment or exemplary embodiments are only examples, and are not
intended to limit the scope, applicability, or configuration in any
way. Rather, the foregoing summary and detailed description will
provide those skilled in the art with a convenient road map for
implementing an exemplary embodiment. It should be understood that
various changes may be made in the function and arrangement of
elements described in an exemplary embodiment without departing
from the scope as set forth in the appended claims and their legal
equivalents.
* * * * *