U.S. patent application number 14/677476 was filed with the patent office on 2015-07-30 for apparatus and methods for cooling rejected heat from server racks.
This patent application is currently assigned to Calvary Applied Technologies, LLC. The applicant listed for this patent is Calvary Applied Technologies, LLC. Invention is credited to Steven Thomas Gizzi, Joerg Burkhard Helbig.
Application Number | 20150216085 14/677476 |
Document ID | / |
Family ID | 49580330 |
Filed Date | 2015-07-30 |
United States Patent
Application |
20150216085 |
Kind Code |
A1 |
Helbig; Joerg Burkhard ; et
al. |
July 30, 2015 |
Apparatus and Methods for Cooling Rejected Heat from Server
Racks
Abstract
The present invention is directed to apparatus and methods for
cooling computer servers and/or electrical equipment in a rack
device for data centers or telecommunication centers.
Inventors: |
Helbig; Joerg Burkhard;
(Ontario, NY) ; Gizzi; Steven Thomas; (Webster,
NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Calvary Applied Technologies, LLC |
Webster |
NY |
US |
|
|
Assignee: |
Calvary Applied Technologies,
LLC
Webster
NY
|
Family ID: |
49580330 |
Appl. No.: |
14/677476 |
Filed: |
April 2, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13709522 |
Dec 10, 2012 |
9016352 |
|
|
14677476 |
|
|
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|
61649577 |
May 21, 2012 |
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Current U.S.
Class: |
29/890.035 |
Current CPC
Class: |
H05K 7/20781 20130101;
Y10T 29/4935 20150115; H05K 7/20709 20130101; F28F 9/007 20130101;
Y10T 29/49359 20150115 |
International
Class: |
H05K 7/20 20060101
H05K007/20; F28F 9/007 20060101 F28F009/007 |
Claims
1. A method for cooling rejected heat from a rack containing
electronic equipment, said method comprising the steps of: a)
providing at least one heat exchanger module having a heat
exchanger; b) providing a heat exchanger mounting frame having
first and second side frame members including a plurality of
longitudinally spaced openings formed therethrough; and c)
providing one or more mounting components affixed to said at least
one heat exchanger module, each of said one or more mounting
components configured for removable attachment to a preselected and
respective one of said mounting frame openings; and d) removably
mounting said at least one heat exchanger module to said heat
exchanger mounting frame by passing said one or more mounting
components through selected ones of said plurality of
longitudinally spaced openings in said mounting frame.
2. The method of claim 1 and further comprising the step of
removably mounting two or more heat exchanger modules in vertically
spaced relation on said heat exchanger mounting frame.
3. The method of claim 1, wherein said mounting frame openings are
configured to allow said one or more mounting components to be
removably attached thereto regardless of whether said cooling door
is rotated 180.degree. with respect to the rack.
4. The method of claim 1 wherein said openings are symmetrically
shaped.
5. The method of claim 4 wherein said one or more mounting
components are in the form of key-hooks operable to freely pass
through a respective mounting frame opening and upon release be
secured thereto via gravity.
6. The method of claim 1 wherein said at least one heat exchanger
comprises a microchannel heat exchanger mounted to a tray having
one or more tray openings formed therethrough, said mounting
components affixed to said tray with said tray being removably
mounted to said mounting frame openings via said mounting
components.
7. The method of claim 6 wherein said at least one heat exchanger
module further comprises at least one fan, and further comprising
the step of removably mounting said at least one fan at the
location of a preselected one of said one or more tray
openings.
8. The method of claim 7 and further comprising a door cover
attached to said mounting frame on the side of said tray opposite
said heat exchanger.
9. The method of claim 8 wherein said door cover includes a pair of
door hinges and further comprising the step of attaching said
mounting frame to said door at a location adjacent said pair of
hinges.
10. The method of claim 9 and further comprising the step of
mounting said door cover to said rack via said pair of hinges
whereby said cooling door is movable between open and closed
positions with respect to said rack.
11. The method of claim 1 wherein said heat exchanger mounting
frame is adapted to removably support one, two or three individual
heat exchanger modules in vertically spaced relation thereon.
12. The method of claim 6 and further comprising the step of
providing one or more removable covers adapted to be removably
positioned over a respective preselected tray opening.
13. The method of claim 6 wherein said heat exchanger includes
refrigerant headers extending therefrom, and wherein said tray
includes one or more notches configured for removable connection to
said refrigerant headers.
14. The method of claim 1 and further comprising the step of
providing a shroud on said cooling door, said shroud being
selectively movable to a position blocking air from passing through
said door at the location of said shroud.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention generally relates to apparatus and
methods for cooling electronic devices. More particularly, the
present invention relates to apparatus and methods for cooling
heated air emanating from electronic equipment to prevent
overheating thereof.
[0002] It is generally well known that electronic devices such as
computers generate heat when they are running, and that the device
can be damaged should the temperature of the device be allowed to
rise above a certain threshold. It is therefore important to ensure
the device has a way of dissipating the generated heat so as to
prevent overheating thereof.
[0003] Many of today's industries and businesses require a host of
computer servers and electrical equipment that are located in what
is referred to as a server room or telecommunication equipment
room. Individual servers or other electronic devices may be
arranged in a server rack which typically comprises a frame having
a plurality of shelves arranged in vertically spaced relationship
with each server or other electronic device positioned upon a
respective shelf. The shelves are vertically spaced from each other
to allow air to circulate between each server in a rack.
[0004] Manufacturers of the servers or other electronic devices
make the housing with openings allowing air to travel through the
device. In this way, heated air generated from the electronic
components located within the housing is allowed to escape through
the openings in the housing. Some electronic device manufacturers
incorporate fans near the housing openings to actively draw the
heated air out of the housing. Other heat management strategies may
be utilized on or adjacent the housing such as fins or the like
which act as heat sinks to help dissipate heat from the device.
[0005] The problem of electronic device heat management becomes
more troublesome and acute when dealing with very large dedicated
server rooms or rooms with high density equipment which generate
significant amounts of heat. In these settings, auxiliary heat
management tactics are required such as using evaporator/condenser
type air conditioning units to cool the air within the server room.
Such air conditioning units are referred to in the industry as
"CRAC" units, which stands for "Computer Room Air Conditioning".
While CRAC units may do the job of keeping the servers at a safe
operating temperature, they are not very efficient in that they
require a lot of electricity to keep the entire volume of the
server room air cool. Maintaining the air in a large server room
cool can thus be a significant, ongoing cost which can increase
exponentially as more server racks are added to the room, rack
densities are increased and/or the room size is expanded. For
industries such as telecommunication companies which require server
rooms the size of football fields, the operational costs of running
CRAC units becomes financially unworkable and alternative, cheaper
cooling strategies are necessary.
[0006] In response to the need for more efficient cooling
strategies, cooling units and assemblies have been proposed which
are placed in close proximity to the individual servers. In this
strategy, the heated air being ejected from the device housing is
cooled prior to it being allowed to mix with the ambient air in the
room. Examples of such units and assemblies may be seen in the
following patents: [0007] U.S. Pat. No. 7,380,657 issued to Chu et
al on Nov. 9, 2010 [0008] U.S. Pat. No. 7,905,105 issued to Fair et
al on Mar. 15, 2011 [0009] U.S. Pat. No. 7,385,810 issued to Chu et
al on Jun. 10, 2008
[0010] While the prior art has provided various apparatus and
approaches for cooling server racks and server rooms, a need
remains for a server rack/room cooling solution which is robust and
reliably operates with little to no chance of harming the
electronic components should a coolant leak from the cooling lines,
has improved operating efficiency over prior art systems, and is
readily customizable to a variety of loaded server rack
configurations and heat loads. The present invention provides
apparatus and methods which successfully addresses the above
performance objectives.
SUMMARY OF THE INVENTION
[0011] Server racks generally comprise a tall, rectangular metal
frame having vertically spaced shelves with the rack being open at
the front and back. A series of racks are typically positioned in
side-by-side relation in spaced rows. The rack open front provides
access to the front of the servers while the open back provides
access to the back of the servers. As explained above, server
housings include openings allowing air to pass therethrough to
assist with extracting heat from the server.
[0012] The present invention provides in a first aspect thereof a
cooling door adapted to be removably mounted to the rear opening of
a server rack. Although the preferred embodiment is a hinged door,
it is understood that the word "door" as used herein is to be
broadly interpreted to mean any type of connection so long as the
door may be moved between a substantially closed and open positions
relative to the server rack. Even further, the door may instead be
free standing or attached by any means to a separate frame or the
like that may be positioned next to but is not necessarily
connected to the server rack (e.g., a frame on lockable caster
wheels that may be rolled adjacent the rack).
[0013] The cooling door includes a protective cooling door cover
preferably formed of sheet metal having air openings which may take
the form of open area hexagonal holes and/or screen-type walls
allowing unrestricted air flow therethrough. The door cover is
preferably connected to the server rack via a hinged connection
allowing the cooling door to pivot between open and closed
positions. In the open position, the server rack rear opening is
accessible to service or otherwise handle the servers on the rack
shelves as needed. In the closed position, the cooling door cover
extends across substantially the entire height and width of the
rack rear opening.
[0014] A rectangular heat exchanger mounting frame is provided
having first and second side frame members with a top frame member
and bottom frame member extending therebetween to define a
rectangular opening. The heat exchanger mounting frame is mounted
between the door cover and the rear opening of the server rack. In
a preferred embodiment, the mounting frame connects to the door
cover in the proximity of the door cover hinges such that the
loaded frame weight is not carried by the door cover but rather is
supported at or adjacent to the location of the door hinge axis.
Separating the mounting frame weight load from the major surface
area of the door cover minimizes physical load stress on the
cooling door cover which has beneficial effects such as reducing
door cover wear and vibrations, for example. A separate hinge
stiffening bar may be provided to extend along the length of the
hinged edge of the door cover and to which the mounting frame may
directly attach which provides further cooling door strength and
stability.
[0015] At least one heat exchanger module is provided for removable
attachment to the heat exchanger mounting frame. In a preferred
embodiment, each heat exchanger module is first mounted to a
respective tray which in turn is mounted to the heat exchanger
mounting frame. The tray includes an array of fan openings in which
a respective fan or, if no fan is required at a particular tray
opening location, a cover may be removably mounted. The fans
operate to help increase the CFM (cubic feet per minute) by drawing
and direct air from the servers through the heat exchangers to cool
it, maximizing the heat exchanger's capacity and then directing the
cooled air through the openings in the door cover and into the
server room.
[0016] In the preferred embodiment, three tray/heat exchanger
modular units of substantially the same size and shape may be
individually, removably mounted in vertically spaced relation to
one another to the heat exchanger mounting frame. In a preferred
embodiment, the removable mounting means comprises a plurality of
longitudinally spaced openings formed through the side frame
members of the mounting frame wherethrough a key-hook, pin, bolt,
or similar mounting component on the tray may removably pass and be
secured. It is preferred that mounting means such as a key-hook or
pin be used which does not require any tools.
[0017] The number and arrangement of individual servers in a server
rack may vary at any given time depending on the needs of the
business. When racks are not fully loaded with servers there are
empty shelves within the rack. Understanding that it is an
inefficient use of energy to have heat exchangers located and
operating at empty shelves, the present invention permits a
technician to very quickly and optimally with no tools alternately
mount and remove individual heat exchanger modules on the cooling
door mounting frame such that the heat exchangers are positioned
only at those locations where servers are located within the rack.
In this regard, it will be appreciated that the technician may
visually identify where to place the heat exchanger module on the
mounting frame (i.e., directly in front of server-occupied rack
shelves), and then align and pass the mounting components (e.g.,
key-hooks or pins) on the heat exchanger unit with and through the
openings on the mounting frame that align with the desired
identified location.
[0018] When the rack is full of servers, the maximum number of heat
exchanger units or modules are mounted to the cooling door counting
frame. Should certain racks lack a server, the heat exchanger
adjacent those shelves may be removed from the mounting frame. In a
preferred embodiment, the empty location on the mounting frame may
be replaced with a closed tray (no fans and no openings thereon) or
other closed panel (mounted in the same removable manner as the
tray/heat exchanger unit) which acts to direct any warm air passing
from the empty rack shelves to the next adjacent heat exchanger
module. It will thus be appreciated that the present system allows
the cooling door to be quickly and easily customized "on the fly"
by the customer (with no special technician training needed) to
accommodate intermittent changes in server numbers and locations
within a rack to thereby minimize energy usage and maximize
operating efficiencies. This modularity also makes maintenance or
replacement of heat exchanger modular units quick to minimize
downtime.
[0019] In yet a further embodiment of the invention, variations in
rack heights may be accommodated by incorporating a movable shroud
located at the top of the door cover which may be moved up or down
on the door cover as needed. For example, the shroud may be moved
to cover the top segment of the door cover to extend it to match
the rack height. This allows one door design to transcend multiple
rack heights and rack manufactures. Example: a design can allow
mounting to 42U through 44U heights and accommodate variation
between manufactures rack heights.
[0020] In a preferred embodiment, the heat exchangers are
micro-channel heat exchangers and refrigerant (e.g., R134A) is the
coolant which travels through supply and return lines positioned
above each row of server racks. Individual rack refrigerant supply
and return lines are directed along the hinge side of the cooling
doors and connect to a respective heat exchanger via quick connect
swivel couplings. The refrigerant will flash to a gas at room
temperature and there is thus no fear of damaging the servers
should a leak occur in the supply or return lines as would be
possible if the coolant used was water, for example, as is used in
many prior art cooling systems.
[0021] A further benefit of having removable mounting of the heat
exchanger modules to a separate door mounting frame is that the
door cover, which includes the door handle, may be attached to the
rack in either a right opening or left opening door orientation.
The door cover and mounting frame (which have been previously
connected together as explained above) may thus be first connected
to the rack in either a left opening or right opening manner by
simply rotating the door 180.degree. as necessary to achieve the
desired orientation. Once the door cover with mounting frame is
attached to the rack, the desired number of tray/heat exchanger
units are removably mounted to the mounting frame. The ability to
removably mount the tray/heat exchanger units to the mounting frame
is not dependent on which 180.degree. orientation of the door cover
and mounting frame is chosen. This is due to the configuration of
the heat exchanger/mounting frame cooperative mounting components
which, as stated above, are preferably in the form of a plurality
of longitudinally spaced openings formed in each side frame member
of the mounting frame and key-hooks extending from the tray/heat
exchanger unit. The openings in the mounting frame are preferably
the same configuration regardless of which 180.degree. orientation
is chosen for the door cover and mounting frame. Each tray/heat
exchanger unit may thus be removably mounted to the mounting frame
by passing the key-hooks through respective openings in the
mounting frame side members. Once inserted and manually released,
gravity secures and maintains the tray/heat exchanger unit on the
mounting frame by virtue of the key-hook hanging within the
respective opening.
[0022] Further operating efficiencies may be realized by
electronically controlling the fans to turn on, off and/or change
speeds in response to the sensed heat load at any given time or
time intervals using temperature or other suitable sensors.
DESCRIPTION OF THE DRAWING FIGURES
[0023] The above-mentioned and other features and advantages of
this invention, and the manner of attaining them, will become
apparent and be better understood by reference to the following
description of the invention in conjunction with the accompanying
drawing, wherein:
[0024] FIG. 1 is a perspective view showing an environment having a
row of server racks with cooling doors mounted thereto in
accordance with an embodiment of the invention;
[0025] FIG. 2 is a perspective view of a door cover of the cooling
door;
[0026] FIG. 3 is a perspective view of a mounting frame and hinge
stiffening bar of the cooling door;
[0027] FIG. 3A is an enlarged detail view of the circled segment
"A" of FIG. 3;
[0028] FIG. 3B is an enlarged detail view of the circled segment
"B" of FIG. 3;
[0029] FIG. 4 is an exploded view of a heat exchanger modular unit
according to a preferred embodiment of the invention;
[0030] FIG. 5 is a perspective view of a cooling door showing the
heat exchanger side thereof which would face the rear of the rack
to which is mounts;
[0031] FIG. 5A is an enlarged detail view of the circled segment
"A" of FIG. 5;
[0032] FIG. 5B is an enlarged detail view of the circled segment
"B" of FIG. 3;
[0033] FIG. 5C is an enlarged perspective view of FIG. 5;
[0034] FIG. 6 is an elevational view of the heat exchanger side of
the cooling door; and
[0035] FIG. 7 is an elevational view of the door cover side of the
cooling door.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0036] Referring now to the drawing figures, there is seen in FIG.
1 a server rack and server room cooling system having a row 10 of
server racks 12 which may be located in a dedicated server room
(not shown). Although a single row of seven server racks 12 is
shown in FIG. 1, it will be readily appreciated that the invention
may be used to cool heated air rejected from any number of server
racks placed in any arrangement.
[0037] It is seen that each server rack 12 generally comprises a
tall, rectangular metal frame having vertically spaced shelves "S"
with the rack being open at the front "F" and back or rear "R". A
series of racks 12 are typically positioned in the side-by-side
relation shown with multiple rows in spaced, parallel relation to
one another. Very large server rooms can have hundreds if not
thousands of server racks. The rack open front "F" provides access
to the front of the servers (the servers themselves are not shown)
while the open rear "R" provides access to the back of the servers.
As explained above, server housings include openings allowing air
to pass therethrough to assist with extracting heat from the
server.
[0038] The present invention provides in a first aspect thereof a
cooling door indicated generally at 14 adapted to be removably
mounted to the rear opening "R" of a server rack 12. The cooling
door 14 includes a protective cooling door cover 16 (FIG. 2)
preferably formed of sheet metal and having screened surfaces 16a
having a pattern of closely spaced openings allowing substantially
unrestricted air flow therethrough. The door cover 16 is connected
to the server rack 14 via one or more hinges 18 (FIGS. 5A and 5C)
which may be secured at openings 16b formed adjacent side edge 16c
of door cover 16 (FIG. 2). Opposite door cover side edge 16d
includes an opening 16e for attachment of a handle 20. The hinged
connection allows the cooling door 14 to pivot between the open
position (server rack 12 at the right end of row 10 in FIG. 1), and
the closed position (all other server racks 12 in row 10). In the
open position, the server rack rear opening "R" is accessible to
service or otherwise handle the servers on the rack shelves "S" as
needed. In the closed position, the cooling door cover 16 extends
across substantially the entire height "H" and width "W" of the
rack rear opening "R".
[0039] As seen best in FIG. 3, a rectangular heat exchanger
mounting frame 22 is provided having first and second side frame
members 24 and 26 with a top frame member 28 and bottom frame
member 30 extending therebetween to define a rectangular opening
32. The heat exchanger mounting frame 22 is mounted inside the door
cover 16 as will be explained below. In a preferred embodiment, the
mounting frame 22 connects to the door cover 16 in the proximity of
the door cover hinges 18 such that the loaded frame weight is not
carried by the major surface area of the door cover 16 but rather
is supported at or adjacent the location of the door hinge axis
X-X. Separating the mounting frame 22 weight load from the major
surface area of the door cover 16 minimizes physical load stress on
the cooling door cover 16 which has beneficial effects such as
reducing door cover wear and vibrations, for example. A separate
hinge stiffening bar 34 may be provided to extend along the length
of the hinged edge of the door cover 16 by aligning and passing
screws through holes 16b and 34b. The mounting frame 22 may
directly attach to stiffening bar 34 via angled brackets 36a and
36b (FIGS. 3 and 3B) which provides further cooling door strength
and stability.
[0040] As seen in FIG. 4, at least one heat exchanger modular unit
40 is provided for removable attachment to the heat exchanger
mounting frame 22. In a preferred embodiment, each heat exchanger
module 40 is first mounted to a respective tray 42 which in turn is
mounted to the heat exchanger mounting frame 22 via brackets
44.
[0041] A heat exchanger 50, preferably an aluminum micro-channel
heat exchanger coil, having supply and return lines 52 and 54,
respectively, is mounted to tray 42 via any suitable mounting
components. For example, tray 42 is seen to include side walls 42a
and 42b having notches 42c wherein heat exchanger supply and return
headers 52a, 54a may fit, respectively, with screws 42d passing
through aligned holes 43,51 in the tray side walls and heat
exchanger, respectively.
[0042] Tray 42 is seen to include an array of fan openings 46 in
which a respective fan 48 or, if no fan is required at a particular
tray opening location 46 due to the absence of a server at that
location, a cover 49 may be removably mounted. The fans 48 operate
to help draw and direct air from the servers in the rack 12 through
the heat exchanger 50 to cool the air, and then direct the cooled
air through the openings 16a in the door cover 16 and into the
server room.
[0043] Referring now also to FIGS. 5-7, in the preferred
embodiment, at least three heat exchanger modular units 40a, 40b
and 40c of substantially the same size and shape may be
individually, removably mounted in vertically spaced relation to
one another to the heat exchanger mounting frame 22. In a preferred
embodiment, the removable mounting means comprises a plurality of
longitudinally spaced openings 24a, 26a formed through respective
side frame members 24 and 26 of the mounting frame 22 wherethrough
the head of a key-hook 60 (FIG. 4, 5B) or other suitable mounting
component on the tray 42 may removably pass and be secured. It is
preferred that mounting means such as a key-hook head be used which
may removably engage the respective opening 24a, 26a without
requiring any tools.
[0044] The number and arrangement of individual servers in a server
rack 12 may vary at any given time depending on the needs of the
business. When racks are not fully loaded with servers there are
empty shelves "S" within the rack. Understanding that it is an
inefficient use of energy to have heat exchangers located and
operating at empty shelves, the present invention permits a
technician to very quickly and optimally with no tools mount or
remove individual heat exchanger modular units 40a, 40b and 40c on
the cooling door mounting frame 22 such that the heat exchanger
modular units are positioned only (or mostly only) at those
locations where servers are located within the rack 12. In this
regard, it will be appreciated that the technician may visually
identify where to place the heat exchanger modular unit 40 on the
mounting frame 22 (i.e., directly in front of server-occupied rack
shelves), and then align and pass the mounting components (e.g.,
key-hooks 60) on the heat exchanger modular unit 40 with and
through the selected openings 24a, 26a on the mounting frame 22
that align with the desired identified location.
[0045] When the rack is full of servers, the maximum number of heat
exchanger modular units 40 are mounted to the cooling door counting
frame 22. Should certain rack shelves "S" lack a respective server,
the heat exchanger modular unit 40 adjacent those shelves may be
removed from the mounting frame 22. In a preferred embodiment, the
empty location on the mounting frame may be replaced with a
completely closed tray (no fans and no openings thereon which may
be removably covered with cover 49, for example, as explained above
(or other closed panel mounted to frame 22 in the same or similar
removable manner as the units 40) which acts to direct any warm air
passing from the empty rack shelves to the next adjacent heat
exchanger modular unit 40. In this regard, it is noted that any
number, including zero, of fans may be utilized as desired,
regardless of the presence of servers in the server racks. With no
fans present and/or operating in the cooling door, the passage of
warm air through the cooling door will emanate from the electronic
equipment fans or other auxiliary fans placed in the proximity of
the server racks. It will thus be appreciated that the present
system allows the cooling door 14 to be quickly and easily
customized "on the fly" by the customer (with no special technician
training needed) to accommodate intermittent changes in server
numbers and locations within a rack 12 to thereby minimize energy
usage and maximize operating efficiencies.
[0046] In yet a further embodiment of the invention, variations in
rack heights may be accommodated by incorporating a movable (e.g.,
freely slidable) shroud 70 located at the top of the door cover 16
which may be moved up or down on the door cover 16 as needed to
accommodate different rack heights "H". For example, today's server
racks come in heights typically varying from 42U to 45U. The
cooling door height may be made to align with the tallest server
rack of 45U. In this instance, shroud 70 would be moved all the way
up so as to be out of the way and not cover any significant part of
the door cover 16. When using the same cooling door for a rack of a
smaller height (e.g., 42U), the shroud 70 may be moved downwardly
to cover the top segment of the door cover 16 that extends above
the shorter rack. In this way, air from the server room located
above the shorter rack is blocked and not directed into the cooling
door, thereby maintaining top operating efficiencies.
[0047] As stated above, in a preferred embodiment, the heat
exchangers are micro-channel heat exchangers and refrigerant (e.g.,
R134A) is the coolant which travels through supply and return lines
52, 54 respectively, the main headers 52b, 54b for a server rack
row 10 (FIG. 1) of which may be positioned above each row 10 of
server racks 12. Individual rack refrigerant supply and return
lines 52, 54 are directed along the hinge side 16c of the cooling
doors (FIGS. 5-5C) and connect to a respective heat exchanger
modular unit 40a, 40b, 40c via quick connect swivel couplings 72.
The refrigerant will flash to a gas at room temperature and there
is thus no fear of damaging the servers should a leak occur in the
supply or return lines 52, 54 as would be possible if the coolant
used was water, for example, as is used in many prior art cooling
systems.
[0048] A further benefit of having removable mounting of the heat
exchanger module units 40a, 40b and 40c to a separate door mounting
frame 22 is that the door cover 16, which includes the door handle
20, may be attached to the rack in either a right opening or left
opening door orientation. The door cover 16 and mounting frame 22
(which have been previously connected together as explained above)
may thus be first connected to a respective rack 12 in either a
left opening or right opening manner by simply rotating the door
180.degree. as necessary to achieve the desired orientation. Once
the door cover 16 with mounting frame 22 is attached to the rack
14, the desired number of heat exchanger modular units 40 are
removably mounted to the mounting frame 22 as explained above. The
ability to removably mount the heat exchanger modular units 40a,
40b, 40c to the mounting frame 22 is not dependent on which
180.degree. orientation of the door cover and mounting frame is
chosen. This is due to the configuration of the heat
exchanger/mounting frame cooperative mounting components which, as
stated above, are preferably in the form of a plurality of
longitudinally spaced openings 24a, 26a formed in each side frame
member 24, 26 of the mounting frame 22 and key-hooks 60, for
example, extending from the heat exchanger modular unit 40. The
openings 24a, 26a in the mounting frame 22 are preferably the same
symmetrical configuration regardless of which 180.degree.
orientation is chosen for the door cover and mounting frame. Each
heat exchanger modular unit 40a, 40b, 40c may thus be removably
mounted to the mounting frame 22 by passing the key-hooks 60
through respective openings 24a, 26a in the mounting frame side
members 24, 26. Once inserted and manually released, gravity
secures and maintains the heat exchanger modular units 40a, 40b,
40c on the mounting frame 22 by virtue of the key-hook 60 or other
like element frictionally engaging the respective opening.
[0049] Further operating efficiencies may be realized by
electronically controlling the fans to turn on, off and/or change
speeds in response to the sensed heat load at any given time or
time intervals using temperature or other suitable sensors.
[0050] While this method and apparatus has been shown and described
with reference to certain preferred embodiments thereof, it will be
understood by those skilled in the art that various changes in form
and details may be made therein without departing from the spirit
and scope of the invention as described.
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