U.S. patent application number 13/109693 was filed with the patent office on 2012-11-22 for method and apparatus for aircraft galley cooling.
This patent application is currently assigned to THE BOEING COMPANY. Invention is credited to Steve G. Mackin, Rodney Millar.
Application Number | 20120291459 13/109693 |
Document ID | / |
Family ID | 46001856 |
Filed Date | 2012-11-22 |
United States Patent
Application |
20120291459 |
Kind Code |
A1 |
Millar; Rodney ; et
al. |
November 22, 2012 |
METHOD AND APPARATUS FOR AIRCRAFT GALLEY COOLING
Abstract
Described in this application for patent is a novel method and
apparatus for providing cooling to an aircraft galley. The aircraft
galley is cooled by means of a central aircraft cooling line,
including a phase change cooling system and a ram air heat
exchanger.
Inventors: |
Millar; Rodney; (Mukilteo,
WA) ; Mackin; Steve G.; (Bellevue, WA) |
Assignee: |
THE BOEING COMPANY
Chicago
IL
|
Family ID: |
46001856 |
Appl. No.: |
13/109693 |
Filed: |
May 17, 2011 |
Current U.S.
Class: |
62/79 ; 62/426;
62/513; 62/89 |
Current CPC
Class: |
B64D 2013/0629 20130101;
F25D 17/02 20130101; Y02T 50/40 20130101; B64D 11/04 20130101; Y02T
50/46 20130101 |
Class at
Publication: |
62/79 ; 62/89;
62/513; 62/426 |
International
Class: |
F25B 41/00 20060101
F25B041/00; F25D 17/06 20060101 F25D017/06 |
Claims
1. A method for cooling the galley of in an aircraft: providing a
preferred cooling line temperature; providing a cooling line
including: a coolant; a heat source; a phase change cooler; and a
heat exchanger in thermal communication with an air source; drawing
heat from said heat source with said coolant; transferring said
coolant to said heat exchanger; transferring said heat from said
coolant to said air source; determining an output temperature of
said coolant as it exits said heat exchanger; and engaging said
phase change cooler if said output temperature is higher than said
preferred temperature.
2. The method of claim 1 wherein said air source is an atmosphere
outside of the aircraft.
3. The method of claim 2 wherein said heat source is a heat
exchanger in thermal communication with a galley.
4. The method of claim 3 wherein said air source comprises a ram
air source.
5. The method of claim 4 wherein said cooling line further includes
a bypass line.
6. The method of claim 5 wherein said cooling line further includes
a diverter valve for diverting a first portion of said coolant
through said bypass line and a second portion of said coolant
through said heat exchanger, and wherein said first and second
portions are combined after said second portion passes through said
heat exchanger.
7. The method of claim 6 wherein said preferred cooling line
temperature comprises a range between a minimum preferred
temperature and a maximum preferred temperature.
8. The method of claim 7 further including the step of adjusting
the diverter valve to maintain said preferred temperature.
9. An apparatus for aircraft galley cooling comprising: a central
cooling line including: a phase change cooling system, a ram heat
exchanger in thermal communication with an atmosphere including an
output temperature, and a galley heat exchanger; a preferred
temperature for said central cooling line; and a galley monument in
thermal communication with said galley heat exchanger; wherein said
phase change cooling system is disengaged if said output
temperature is less than or equal to said preferred
temperature.
10. The apparatus of claim 9 further comprising a fan adjacent said
galley heat exchanger, said fan for aiding thermal communication
between said galley heat exchanger and said galley monument.
11. The apparatus of claim 9 wherein said central cooling line
further includes a coolant.
12. The apparatus of claim 11 further comprising a bypass line for
diverting said coolant around said ram heat exchanger.
13. The apparatus of claim 12 further comprising a diverter valve
for transferring all or a portion of said coolant through said
bypass line.
14. A method of regulating temperature in a central aircraft
cooling line comprising the steps of: providing a phase change
cooling system in thermal communication with said central aircraft
cooling line; providing a heat exchanger in thermal communication
with an exterior of said aircraft and said central aircraft cooling
line; determining a heat loss through said heat exchanger;
selectively engaging or disengaging said phase change cooling
system depending on said heat loss.
15. The method of claim 14 further comprising a heat source.
16. The method of claim 15 further comprising the step of
determining a heat gain through said heat source.
17. The method of claim 16 further comprising determining a net
heat gain based on said heat loss and said heat gain.
18. The method of claim 17 wherein said phase change cooling system
comprises a plurality of refrigerators.
19. The method of claim 18 further comprising the step of engaging
one or more of said plurality of refrigerators if said net heat
gain is positive.
20. The method of claim 17 further comprising the step of diverting
a portion of said coolant around said heat exchanger if said net
heat gain is negative.
Description
BACKGROUND
[0001] The present invention relates to a configurable cooling
apparatus, and more specifically to a heat exchanger circuit for
use in cooling one or more aircraft galley monuments.
[0002] Galleys in private or commercial aircraft are very common.
These areas store food and beverages for aircraft passengers on
long flights and have become a staple of the airline industry.
These galleys often incorporate parking areas (or galley cooling
units) where a food transport cart can be stored. The galley
cooling units include a cooling element for keeping the food at a
temperature lower than the surrounding environment.
[0003] One method of providing cooling to these galley cooling
units is the use of a central aircraft cooling line that provides
cooling throughout the aircraft and a heat exchanger between the
central aircraft cooling line and the galley cooling unit. A fan
module may also be provided for circulating the cool air into or
over the galley cooling unit to provide cooling.
[0004] The central aircraft cooling line contains a fluid which may
have a high specific heat, that is, the fluid is able to absorb
large amounts of heat without a significant change in temperature.
This allows the fluid of the central aircraft cooling line to
maintain a relatively stable temperature while absorbing heat from
multiple locations.
[0005] The central aircraft cooling line is typically a closed
system where the cooling fluid (or coolant) is cycled through the
cooling line to draw heat from various components. Therefore,
whatever heat is absorbed by the coolant must be extracted to
maintain cooling.
[0006] The central aircraft cooling line is currently cooled by use
of a phase change circuit that utilizes a refrigerant in a separate
and closed evaporator/condenser fluid line to cool the central
aircraft cooling line, and therefore the coolant contained therein.
This process is well known to those in the art and generally
includes a compressor for compressing a gas, a condenser for
converting the gas into a liquid, and an evaporator for converting
the liquid into a gas to thereby draw heat from the surrounding
environment.
[0007] The compressor of a phase change cooling circuit produces
heat in excess of that absorbed by the evaporator and this heat is
dissipated through the condenser. As the gas is condensed into a
liquid, heat is released and preferably removed by means of a
tertiary closed-circuit cooling line.
[0008] The tertiary closed-circuit cooling line generally cycles
between a first heat exchanger a second heat exchanger. The first
heat exchanger is in thermal communication with the tertiary line
and the condenser and the second heat exchanger is in thermal
communication with the tertiary line and the ram air. Ram air is
air that is drawn from the boundary layer (or near boundary layer)
of the outside of the aircraft and passed through a heat exchanger
matrix. Ram air at approximately 35,000 feet is typically
-55.degree. C. (-67.degree. F.), and may vary by up to 20.degree.
C. (36.degree. F.) depending on weather conditions.
[0009] The current method of providing cooling to the galley
cooling units requires a number of phase change coolers to provide
adequate cooling for the central aircraft cooling line. A cooling
method and apparatus that would remove one or more of the phase
change coolers would reduce the weight of the aircraft and improve
efficiency.
SUMMARY
[0010] Described herein is a novel method for cooling the galley of
an aircraft. The method includes the steps of providing a preferred
temperature for a cooling line, and the cooling line includes a
coolant, a heat source, a phase change cooler, and a heat
exchanger. Heat from the heat source is collected by means of the
coolant which is then transferred to the heat exchanger. The heat
is transferred from the heat exchanger to the air source and the
output temperature of the coolant from the heat source is
determined. If the output temperature is higher than the preferred
temperature, than the phase change cooler is engaged to provide
supplemental cooling of the coolant.
[0011] Also described herein is an apparatus for aircraft galley
cooling. The apparatus comprises a central cooling line, a galley
monument, and a preferred temperature for the central cooling line.
The cooling line further includes a phase change cooling system, a
ram heat exchanger and a galley heat exchanger in thermal
communication with the galley monument. If an output temperature of
the heat exchanger is less than or equal to the preferred
temperature, then the phase change cooling system may be
disengaged.
[0012] Also described herein is a method for regulating temperature
in a central aircraft cooling line. The method includes the steps
of providing a phase change cooling system and a heat exchanger,
both in thermal communication with the central aircraft cooling
line. The heat loss through the heat exchanger is determined and
the phase change cooling system is selectively engaged or
disengaged based on this heat loss.
BRIEF DESCRIPTION OF DRAWINGS
[0013] FIG. 1 shows a view of an aircraft according to one
embodiment of the invention.
[0014] FIG. 2 shows a schematic view of the cooling system
according to one embodiment.
[0015] FIG. 3 shows a schematic view of a phase change cooler
according to one embodiment.
[0016] FIG. 4 shows a top plan view of a heat exchanger.
[0017] FIG. 5 shows a schematic view of a galley cooling unit
according to the present invention.
[0018] FIG. 6 shows a schematic view of the cooling system
according to an alternative embodiment.
[0019] FIG. 7 shows a flowchart according to one embodiment of the
invention.
DETAILED DESCRIPTION
[0020] FIG. 1 shows an illustration of an aircraft 100 according to
one embodiment of the present invention. The aircraft generally
consists of fuselage 102, wings 104, tail, 106, and nose 108
sections. Further, a ram air intake 110 is located on the aircraft
fuselage 102 which provides air cooling.
[0021] FIG. 2 shows a schematic view of the central aircraft
cooling line 112 that provides cooling throughout the aircraft 100.
The central aircraft cooling line 112 is a continuous closed
circuit, but will generally be described as originating at a phase
change cooling system 114. The central aircraft cooling line 112
may then pass to the aft section of the circuit where it interacts
with the various galley cooling units 116. The central aircraft
cooling line 112 may next pass through a cargo hold heat exchanger
118 to cool cargo air 117 and a cabin air heat exchanger 119 to
cool cabin air 121. Finally, the central aircraft cooling line 112
is run through a ram air heat exchanger 120 and through a pump 122
before returning to the phase change cooling system 114 where heat
is extracted.
[0022] The phase change cooling system 114 is generally shown in
FIG. 3 and consists of a closed refrigerant line 124, evaporator
126, compressor 128, expansion valve 130 and condenser 132. As is
well known in the art, a phase change cooling system 114 generally
operates by compressing a gas by means of the compressor 128;
dissipating heat from the gas through a condenser 132, thereby
causing the gas to condense into a fluid; passing the fluid through
an expansion valve 130; and allowing the gas to expand in an
evaporator 126, thereby drawing heat from the surrounding area into
the fluid of the closed refrigerant line 124.
[0023] As further shown in FIG. 3, the evaporator 126 may be
adjacent to a heat exchanger matrix 134 that is part of the central
aircraft coolant line 112. As the refrigerant in the closed
refrigerant line 124 evaporates, heat will be drawn from the heat
exchanger matrix 134 of the central aircraft coolant line 112. The
winding path of the heat exchanger matrix 134 and evaporator 126
maximizes heat transfer between the two closed systems.
[0024] Further shown in FIG. 3, adjacent to the condenser 132 may
be a secondary cooling line 136 which includes a secondary cooling
heat exchanger matrix 138 in thermal communication with the
condenser 132. As will be appreciated by those having skill in the
art, the secondary cooling heat exchanger matrix 138 includes a
winding path to maximize heat transfer between the condenser 132
and the secondary cooling heat exchanger matrix 138. This secondary
cooling line 136 therefore carries heat away from the condenser
132.
[0025] As further shown in FIG. 2, a number of phase change cooling
units 114 may be positioned in series, where each unit 114 reduces
the temperature in the central aircraft cooling line 112. According
to this arrangement, the output from each heat exchanger matrix 134
would be in fluid communication with the input of the next heat
exchanger matrix 134 so that the fluid of the central aircraft
cooling line 112 is progressively reduced. Alternatively, although
not shown, the phase change cooling units 114 may be provided in
parallel, whereby each cooling unit 114 cools a portion of the
central aircraft cooling line 112.
[0026] As further shown in FIG. 3, the secondary cooling line 136
draws heat from the condensers 132 of the phase change cooling
units 114. The secondary cooling line 136 is shown to engage the
cooling units 114 in parallel so that the temperature of the
secondary cooling line 136 may be approximately equal across each
condenser 132. Alternatively, the secondary cooling line 136 may be
arranged so that the condensers 132 are in series.
[0027] As further shown in FIG. 2, according to one embodiment of
the invention the secondary cooling line 136 is in thermal
communication with an external heat sink 140. This external heat
sink 140 may be a ram air heat exchanger positioned in a pack bay
142 (see FIG. 1) of the aircraft 100, or may consist of a secondary
line and heat exchanger.
[0028] As shown in FIG. 4, the ram heat exchanger 120 generally
consists of a serpentine shape in thermal communication with ram
air 144 that is passed over the heat exchanger 120. The ram air 144
draws heat from the central aircraft cooling line 112 by means of
this thermal communication.
[0029] Returning to FIG. 2, the central aircraft cooling line 112
may include a number of galley cooling units 116 arranged in
parallel with one another. These cooling units 116 are further
illustrated in FIG. 5. Those skilled in the art will appreciate
that the galley cooling units may be alternatively arranged in
series, or in an arrangement combining parallel and series.
[0030] As shown in FIG. 5, the galley cooling unit 116 generally
includes a galley heat exchanger 146 with both an input 148 and
output 150. As with previous heat exchangers, the galley heat
exchanger 146 includes a serpentine construction. Also shown is an
optional fan module 152 that circulates air into and out from the
area adjacent a number of galley carts 153. There may also be
present temperature sensors 154 that measure the temperature of the
air as it is cycled over the carts 153 and returned. This provides
feedback to a control system (not shown) so that the temperature of
the food can be regulated.
[0031] Returning again to FIG. 2, the central aircraft cooling line
112 may include a cargo hold heat exchanger 118 which may transfer
heat to or from the air of the cargo hold, depending on the
relative temperatures of the cargo hold air and aircraft cooling
line 112. This cargo hold heat exchanger 118 is substantially
similar to the heat exchangers described above.
[0032] Finally, the central aircraft cooling line 112 is passed
through the ram heat exchanger 120 which includes a serpentine
arrangement similar to heat exchangers previously described. Heat
is drawn from the ram heat exchanger 120 by means of ram air 144
that passes over the heat exchanger 120. This ram air is
significantly cold at altitude (for example, -55.degree. C. at
35,000 feet) to provide sufficient cooling for the cold air
system.
[0033] As shown in FIG. 6, each of the heat exchangers 118, 120 may
include a bypass path 156 and diverter valve 158 that allows flow
of coolant to be diverted around the heat exchangers 118, 120. The
diverter valve 158 may be configured to divert some or all of the
fluid around the heat exchanger, thereby regulating the temperature
of the fluid. Temperature sensors 154 can measure the temperature
of the un-cooled fluid (A), the cooled fluid (B) and the combined
fluid (C) and regulate the position of the diverter valve 158 to
control the temperature in the line 112.
[0034] The system is preferably automated to maintain a preferred
temperature within the system. Because of the electrical draw and
increased heat generated by the phase change coolers 114, it is
desirable to reduce the time that these systems are in use.
Therefore, a system as illustrated in the flowchart of FIG. 7 may
be utilized to improve the system.
[0035] As shown in FIG. 7, the first step in regulating the
temperature of the central aircraft cooling line 112 is to
determine the fluid temperature entering (T.sub.IN) and leaving
(T.sub.OUT) the ram air heat exchanger 120. This information can be
used to determine the amount of heat removed from the cooling line
112 by the ram air heat exchanger 120 based on the difference
between these temperatures, flow rate through the cooling line 112,
and specific heat of the coolant, which are all known
variables.
[0036] The output temperature (T.sub.OUT) of the ram heat exchanger
120 is next compared against a known preferred temperature
(T.sub.PREF) of the cooling line. This preferred temperature
(T.sub.PREF) may be a constant or determined based on the amount of
cooling required. For example, if fewer galley cooling units 116
are in use, the temperature of the central aircraft cooling line
112 does not need to be as cool as less heat is being introduced
into the line 112. The preferred temperature (T.sub.PREF) is
typically within a range from a minimum preferred temperature
(T.sub.MIN) to a maximum preferred temperature (T.sub.mAx). When a
temperature is referred to as "equal to" the preferred temperature
(T.sub.PREF), this means that the temperature is within the
acceptable range between the minimum (T.sub.MIN) and maximum
(T.sub.mAx) preferred temperatures. A temperature referred to as
"below" or "lower than" the preferred temperature (T.sub.PREF) is a
temperature that is below the minimum preferred temperature
(T.sub.MIN). A temperature referred to as "above" or "higher than"
the preferred temperature (T.sub.PREF) is a temperature that is
above the maximum preferred temperature (T.sub.MAX).
[0037] If the output temperature (T.sub.OUT) of the ram heat
exchanger 120 is above the preferred temperature (T.sub.PREF), then
the ram heat exchanger 120 is not dissipating enough heat to cool
the central aircraft cooling line 112 on its own, and supplemental
cooling from the phase change coolers 114 must be introduced. Based
on the temperature difference between the ram heat exchanger 120
output (T.sub.OUT) and the preferred temperature (T.sub.PREF), one
or more phase change coolers 114 may be engaged to produce the
desired cooling. Alternatively, phase change coolers 114 may be
engaged in sequence to progressively step down the temperature in
the central aircraft cooling line 112.
[0038] The output temperature (T.sub.OUT) of the ram heat exchanger
120 may also be below the preferred temperature (T.sub.PREF) for
the central aircraft cooling line 112. In this case, the phase
change coolers 114 do not need to be engaged, and control of the
system will shift to the temperature sensor 154 that measures the
combined temperature (T.sub.COMB).
[0039] The combined temperature (T.sub.COMB) is the temperature of
the fluid from the ram heat exchanger 120 and bypass path 156
modified by the proportion diverted by the diverter valve 158. The
combined temperature (T.sub.COMB) may be modified by adjusting the
diverter valve 158 to allow more or less flow through the bypass
path 156. The fluid flowing through the bypass path 156 maintains
the same high temperature (T.sub.OUT) as the input fluid to the ram
heat exchanger 120, and therefore is used to raise the temperature
of the central aircraft heating line 112 to prevent the combined
temperature (T.sub.COMB) from falling below the preferred
temperature (T.sub.PREF).
[0040] The combined temperature (T.sub.COMB) may be either lower
than, equal to, or higher than the preferred temperature
(T.sub.PREF). If the combined temperature is below the preferred
temperature (T.sub.PREF), then the diverter valve 158 may be
adjusted to increase the flow through the bypass path 156 so that
the combined temperature (T.sub.COMB) reaches the preferred
temperature (T.sub.PREF). This is preferably maintained by a
positive feedback control system that monitors and adjusts the
diverter valve 158 to maintain the preferred temperature
(T.sub.PREF).
[0041] If the combined temperature (T.sub.COMB) is higher than the
preferred temperature (T.sub.PREF) (and the output temperature
(T.sub.OUT) is less than the preferred temperature (T.sub.PREF)),
then the diverter valve 158 must be adjusted to reduce the flow
through the bypass path 156 to thereby reduce the temperature
(T.sub.COMB) of the combined fluid.
[0042] If the combined temperature (T.sub.COMB) is equal to the
preferred temperature (T.sub.PREF) (and the output temperature
(T.sub.OUT) is less than the preferred temperature (T.sub.PREF)),
then the flow through the bypass path 156 is appropriate and should
be maintained.
[0043] It may be appreciated by those having skill in the art that
the bypass path 156 and diverter valve 158 may be combined with any
of the heat exchanger matrices in the above described system, and a
control system may be devised to monitor input, output, and
combined temperatures within the central aircraft cooling line 112.
For example, sensors (not shown) may detect the temperature or
presence of galley carts 153 in one or more of the galley cooling
units 116 and selectively allow flow through the heat exchanger 146
of the galley cooling unit 116 to conserve energy.
[0044] The invention has been described as utilizing a ram heat
exchanger in communication with an exterior air source to provide
heat transfer from the central cooling line. However, the ram heat
exchanger may be replaced with any heat exchanger in thermal
communication with outside air. One example of such a heat
exchanger is a series of cooling lines adjacent or near the skin of
the aircraft that utilize conduction to transfer heat from the
cooling line to the aircraft skin and then to the outside air.
[0045] The invention has been generally described with respect to a
preferred embodiment. This embodiment is intended to be exemplary
rather than limiting. Further, those skilled in the art will
recognize that various modifications of the described embodiment
may be made without departing from the scope of the invention. Any
limitations will appear in the claims as allowed.
* * * * *