U.S. patent application number 11/736965 was filed with the patent office on 2008-01-24 for case for a liquid submersion cooled electronic device.
This patent application is currently assigned to Hardcore Computer, Inc.. Invention is credited to Chad Daniel Attlesey, Allen James Berning, R. Daren Klum.
Application Number | 20080017355 11/736965 |
Document ID | / |
Family ID | 38723962 |
Filed Date | 2008-01-24 |
United States Patent
Application |
20080017355 |
Kind Code |
A1 |
Attlesey; Chad Daniel ; et
al. |
January 24, 2008 |
CASE FOR A LIQUID SUBMERSION COOLED ELECTRONIC DEVICE
Abstract
A portable, self-contained liquid submersion cooling system that
is suitable for cooling a number of electronic devices, including
cooling heat-generating components in computer systems and other
systems that use electronic, heat-generating components. The
electronic device includes a housing having an interior space, a
dielectric cooling liquid in the interior space, a heat-generating
electronic component disposed within the space and submerged in the
dielectric cooling liquid, and a pump for pumping the liquid into
and out of the space, to and from a heat exchanger that is fixed to
the housing outside the interior space. The heat exchanger includes
a cooling liquid inlet, a cooling liquid outlet, and a flow path
for cooling liquid therethrough from the cooling liquid inlet to
the cooling liquid outlet. An air-moving device such as a fan can
be used to blow air across the heat exchanger to increase heat
transfer.
Inventors: |
Attlesey; Chad Daniel;
(Rochester, MN) ; Klum; R. Daren; (Shoreview,
MN) ; Berning; Allen James; (Rochester, MN) |
Correspondence
Address: |
HAMRE, SCHUMANN, MUELLER & LARSON, P.C.
P.O. BOX 2902
MINNEAPOLIS
MN
55402-0902
US
|
Assignee: |
Hardcore Computer, Inc.
Rochester
MN
|
Family ID: |
38723962 |
Appl. No.: |
11/736965 |
Filed: |
April 18, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60800715 |
May 16, 2006 |
|
|
|
Current U.S.
Class: |
165/104.33 ;
165/121 |
Current CPC
Class: |
H01L 2924/0002 20130101;
H05K 7/20236 20130101; G06F 2200/201 20130101; G06F 1/20 20130101;
H01L 2924/0002 20130101; H05K 7/20781 20130101; G06F 1/181
20130101; H01L 23/427 20130101; H01L 2924/00 20130101 |
Class at
Publication: |
165/104.33 ;
165/121 |
International
Class: |
F28D 15/00 20060101
F28D015/00; H01L 23/467 20060101 H01L023/467 |
Claims
1. An electronic device, comprising: a housing having an interior
space; a heat-generating component disposed within the interior
space; a dielectric cooling liquid within the interior space with
the heat-generating component being submerged in the dielectric
cooling liquid in direct contact with the cooling liquid; a pump
within the interior space and submerged in the dielectric cooling
liquid, the pump including an inlet and an outlet; a heat exchanger
fixed to the housing outside the interior space, the heat exchanger
including a cooling liquid inlet, a cooling liquid outlet, and a
flow path for cooling liquid therethrough from the cooling liquid
inlet to the cooling liquid outlet; a first passageway connecting
the pump outlet to the cooling liquid inlet; a second passageway
connecting the cooling liquid outlet to the interior space; and an
air-moving device adjacent to the heat exchanger, the air-moving
device configured to move air past the heat exchanger.
2. The electronic device of claim 1, wherein the housing defines
the interior space.
3. The electronic device of claim 1, wherein the electronic device
is a computer and the heat-generating component is at least one of
a processor, memory, and a power supply.
4. The electronic device of claim 1, wherein air-moving device is a
fan.
5. The electronic device of claim 1, wherein the heat exchanger is
adjacent to a wall of the housing.
6. The electronic device of claim 1, further comprising a
high-efficiency particulate air filter adjacent to the air-moving
device.
7. The electronic device of claim 1, further comprising a hard
drive mechanism disposed in the interior space and submerged in the
dielectric cooling liquid, and a snorkel connected to the hard
drive mechanism and connected with the exterior of the interior
space using a conduit to achieve pressure equilibrium between the
hard drive and outside air pressure.
8. The electronic device of claim 1, wherein the dielectric cooling
liquid is a soy-based dielectric liquid.
9. An electronic device, comprising: a housing defining a
liquid-tight interior space, a liquid inlet to the interior space
from an exterior of the interior space, and a liquid outlet from
the interior space to the exterior thereof; a heat-generating
component disposed within the interior space; a dielectric cooling
liquid within the interior space with the heat-generating component
being submerged in the dielectric cooling liquid in direct contact
with the cooling liquid; a heat exchanger fixed to the housing
outside the interior space, the heat exchanger including a cooling
liquid inlet exterior of the interior space, a cooling liquid
outlet exterior of the interior space, and a flow path for cooling
liquid therethrough from the cooling liquid inlet to the cooling
liquid outlet; and a first fluid passage connecting the liquid
outlet to the cooling liquid inlet, and a second fluid passage
connecting the liquid inlet to the cooling liquid outlet.
10. The electronic device of claim 9, wherein the electronic device
is a computer and the heat-generating component is at least one of
a processor, memory, and a power supply.
11. The electronic device of claim 9, further comprising an
air-moving device adjacent to the heat exchanger to move air past
the heat exchanger.
12. The electronic device of claim 9, wherein the beat exchanger is
adjacent to a wall of the housing.
13. The electronic device of claim 9, further comprising a hard
drive mechanism disposed in the interior space and submerged in the
dielectric cooling liquid, and a snorkel connected to the hard
drive mechanism and in communication with the exterior of the
interior space to achieve pressure equilibrium between the hard
drive and outside air pressure.
14. The electronic device of claim 9, wherein the dielectric
cooling liquid is a soy-based dielectric liquid.
15. A personal computer with a self-contained liquid cooling system
comprising: a case having an interior space; a motherboard disposed
within the interior space, the motherboard including at least one
heat-generating component disposed thereon; a dielectric cooling
liquid within the interior space with the heat-generating component
being submerged in the dielectric cooling liquid in direct contact
with the cooling liquid; a pump including an inlet and an outlet
for pumping cooling liquid into and from the interior space; a heat
exchanger fixed to the case outside the interior space, the heat
exchanger including a cooling liquid inlet, a cooling liquid
outlet, and a flow path for cooling liquid therethrough from the
cooling liquid inlet to the cooling liquid outlet; a first fluid
passage connecting the pump outlet to the cooling liquid inlet; and
a second fluid passage connecting the cooling liquid outlet to the
interior space.
16. The personal computer of claim 15, wherein the case defines the
interior space.
17. The personal computer of claim 15, wherein the heat-generating
component comprises at least one of a processor, memory, and a
power supply.
18. The personal computer of claim 15, further comprising an
air-moving device adjacent to the heat exchanger to move air past
the heat exchanger.
19. The personal computer of claim 18, wherein the air-moving
device comprises a fan.
20. The personal computer of claim 18, further comprising a
high-efficiency particulate air filter adjacent to the air-moving
device.
21. The personal computer of claim 15, wherein the heat exchanger
is adjacent to a wall of the case.
22. The personal computer of claim 15, wherein the pump is disposed
within the interior space and is submerged in the cooling
liquid.
23. The personal computer of claim 15, further comprising a hard
drive mechanism disposed in the interior space and submerged in the
dielectric cooling liquid, and a snorkel connected to the hard
drive mechanism and in communication with the exterior of the
interior space to achieve pressure equilibrium between the hard
drive and outside air pressure.
24. The personal computer of claim 15, wherein the dielectric
cooling liquid is a soy-based dielectric liquid.
25. A cooling system for a power supply of a computer, comprising:
a housing having an interior space in which heat-generating
components of the power supply are disposed, a liquid inlet to the
interior space from an exterior of the housing, and a liquid outlet
from the interior space to the exterior of the housing; a
dielectric cooling liquid within the interior space in which the
heat-generating components of the power supply are submerged in
direct contact with the cooling liquid; a heat exchanger attached
to the housing, the heat exchanger including a cooling liquid inlet
exterior of the interior space, a cooling liquid outlet exterior of
the interior space, and a flow path for cooling liquid therethrough
from the cooling liquid inlet to the cooling liquid outlet; a first
fluid passage connecting the liquid outlet to the cooling liquid
inlet, and a second fluid passage connecting the liquid inlet to
the cooling liquid outlet; and a pump circulating the cooling
liquid between the interior space and the heat exchanger.
26. The cooling system of claim 25, wherein the power supply is
mounted on a board.
27. A method of cooling a computer power supply of a computer,
comprising: submerging heat-generating components of the power
supply in a dielectric cooling liquid in an interior space within
the computer so that the heat-generating components are in direct
contact with the cooling liquid; and circulating the dielectric
cooling liquid to an external heat exchanger that is mounted on the
computer for cooling the dielectric cooling liquid.
Description
[0001] This application claims the benefit of U.S. Provisional
Application 60/800,715 filed May 16, 2006, which is incorporated by
reference herein in its entirety.
TECHNICAL FIELD
[0002] This disclosure relates to a liquid submersion cooling
system, and in particular, to a liquid submersion cooling system
that is suitable for cooling electronic devices, including computer
systems.
BACKGROUND
[0003] A significant problem facing the computer industry is heat.
The higher the temperature a component operates at, the more likely
it is to fail. Also, high temperatures, while not causing
catastrophic failures, can create data processing errors. Operation
at high temperatures can cause power fluctuations that lead to
these errors within a central processing unit (CPU) or on the
motherboard anywhere that data management is handled. Despite
efforts at reducing waste heat while increasing processing power,
each new CPU and graphics processing unit (GPU) released on the
market runs hotter than the last. Power supply and motherboard
components required to provide power and handle signal processing
also are producing more and more heat with every new
generation.
[0004] The use of liquids in cooling systems to cool computer
systems is known. One known method of cooling computer components
employs a closed-loop, 2-phase system 10 as illustrated in FIG. 1.
The 2-phase system 10 is employed to passively cool the north 12
and south 14 bridge chips. The vapor travels through a tube 16 to a
cooling chamber 18, the vapor turns back into liquid, and the
liquid is returned by tube 20 to the chips 12, 14 for further
cooling. In another known liquid cooling system, internal pumps
move liquid past a hot plate on a CPU and then the heated liquid is
pumped into a finned tower that passively cools the liquid and
returns it to the plate.
[0005] In the case of large-scale, fixed-installation
supercomputers, it is known to submerge the active processing
components of the supercomputer in inert, dielectric fluid. The
fluid is typically allowed to flow through the active components
and then it is pumped to external heat exchangers where the fluid
is cooled before being returned to the main chamber.
[0006] Despite prior attempts to cool computer components, further
improvements to cooling systems are necessary.
SUMMARY
[0007] A liquid submersion cooling system is described that is
suitable for cooling a number of electronic devices, including
cooling heat-generating components in computer systems and other
systems that use electronic, heat-generating components. Examples
of electronic devices to which the concepts described herein can be
applied include, but are not limited to, desktop computers and
other forms of personal computers including laptop computers,
console gaming devices, hand-held devices such as tablet computers
and personal digital assistants (PDAs); servers including blade
servers; disk arrays/storage systems; storage area networks;
storage communication systems; work stations; routers;
telecommunication infrastructure/switches; wired, optical and
wireless communication devices; cell processor devices; printers;
power supplies; displays; optical devices; instrumentation systems,
including hand-held systems; military electronics; etc.
[0008] The electronic device has a portable, self-contained liquid
submersion cooling system. The electronic device can include a
housing having an interior space. A dielectric cooling liquid is
contained in the interior space, and a heat-generating electronic
component or a plurality of components are disposed within the
space and submerged in the dielectric cooling liquid. The active
heat-generating electronic components are in direct contact with
the dielectric cooling liquid. Alternatively, the components are
indirectly cooled by the cooling liquid. A pump is provided for
transporting the cooling liquid into and out of the space, to and
from a heat exchanger that is fixed to the exterior of the housing.
The heat exchanger includes a cooling liquid inlet, a cooling
liquid outlet and a flow path for the cooling liquid from the
cooling liquid inlet to the cooling liquid outlet. Either the pump
can be placed within the interior space so that it is submerged in
the cooling liquid or the pump can be disposed outside the interior
space.
[0009] In another embodiment, an electronic device is provided that
relies on convection of the cooling liquid, thereby eliminating the
need for a pump. In this embodiment, the heat-generating electronic
component is disposed within the interior space that contains the
dielectric cooling liquid. Convection causes the cooling fluid to
flow out of the interior space to the heat exchanger, and from the
heat exchanger back into the interior space.
[0010] An air-moving device, such as a fan, can be used to move air
past the heat exchanger to increase the heat transfer from the heat
exchanger. In addition, a filter, for example, a HEPA filter, can
be located adjacent to the air-moving device for filtering the
air.
[0011] When the electronic device is a computer, for example, a
personal computer, a motherboard is disposed within the interior
space. The motherboard includes a number of heat-generating
electronic components. Heat-generating components of the computer
may include: one or more CPUS, one or more GPUs, one or more memory
modules such as random access memory (RAM), one or more power
supplies, one or more mechanical storage devices such as hard
drives, and other storage devices, including solid-state memory
storage units. All of these components can be submerged in the
cooling liquid.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 shows a cooling system employing a 2-phase system 10
to passively cool the north and south bridge chips.
[0013] FIG. 2 is a view of an embodiment of a portable,
self-contained liquid submersion cooling system on a personal
computer.
[0014] FIGS. 3A and 3B are perspective and end views, respectively,
showing components of the liquid submersion cooling system of FIG.
2.
[0015] FIG. 4 is a perspective view of the computer case.
[0016] FIGS. 5A, 5B, and 5C are perspective, top and side views,
respectively, of the lid of the computer case showing the
pass-through connector.
[0017] FIG. 6 is a detailed illustration of the pass-through
connector.
[0018] FIG. 7 is a perspective view of the motherboard or main
board of the computer.
[0019] FIGS. 8A and 8B are perspective and side views,
respectively, showing daughter cards on the motherboard and showing
engagement with the lid.
[0020] FIG. 9 illustrates a subassembly including the case,
motherboard and daughter cards in the case, and the lid.
[0021] FIG. 10 illustrates the subassembly of FIG. 9 with a pump
within the case.
[0022] FIGS. 11A and 11B are perspective and end views,
respectively, of a subassembly that includes a hard drive within
the case.
[0023] FIGS. 12A and 12B are perspective and end views,
respectively, of a subassembly that includes multiple heat
exchangers.
[0024] FIGS. 13A and 13B are perspective and end views,
respectively, of a subassembly that includes a single heat
exchanger.
[0025] FIG. 14 is an end view similar to FIG. 12B showing how
convection cooling works.
[0026] FIG. 15 is an illustration of a prototype computer that
incorporates the liquid submersion cooling system, where the video
boards and pump are visible in the case and the radiators are
visible, mounted on the sides.
[0027] FIG. 16 is an illustration of the prototype computer of FIG.
15 showing the front and top of the case.
[0028] FIG. 17 is a perspective view of another embodiment of a
portable, self-contained liquid submersion cooling system on a
personal computer.
[0029] FIG. 18 is a side view of the computer shown in FIG. 17.
[0030] FIG. 19 is an end view of the computer shown in FIG. 17.
[0031] FIG. 20 is a perspective view similar to FIG. 17 but with
the motherboard assembly partially lifted from the interior
space.
[0032] FIG. 21 is an end view of the motherboard assembly removed
from the computer.
[0033] FIG. 22 is a perspective view of the motherboard
assembly.
[0034] FIG. 23 is a side view of the motherboard assembly.
[0035] FIG. 24 illustrates the motherboard assembly in a raised
position.
[0036] FIG. 25 is a perspective view of the computer case with the
motherboard assembly and lid removed.
[0037] FIG. 26 is a side view of the heat exchanger.
[0038] FIG. 27 illustrates a pair of heat exchanger plates used to
form the heat exchanger.
[0039] FIG. 28 is a perspective view of the heat exchanger and
fan.
[0040] FIG. 29 illustrates a snorkel attachment for use with a hard
drive.
[0041] FIGS. 30A, 30B, and 30C illustrate use of the snorkel
attachment on a hard drive.
[0042] FIGS. 31A, 31B and 31C illustrate details of the AC current
cut-off mechanism associated with the lid.
DETAILED DESCRIPTION
[0043] A liquid submersion cooling system is described that is
suitable for cooling a number of electronic devices, including
cooling heat-generating components in computer systems and other
systems that use electronic, heat-generating components. In the
case of computer systems, the liquid submersion cooling system
permits creation of, for example, desktop-sized computers with
scalable architectures where it is possible to produce 32 to 64, or
more, processor core systems (8 sockets.times.8 cores=64
processor). The processing power of these desktop-sized computer
systems will rival or surpass supercomputing systems that, until
now, would require significant floor space.
[0044] Examples of electronic devices to which the concepts
described herein can be applied include, but are not limited to,
desktop computers and other forms of personal computers including
laptop computers; console gaming devices, hand-held devices such as
tablet computers, wearable computers and personal digital
assistants (PDAs); servers including blade servers; disk
arrays/storage systems; storage area networks; storage
communication systems; work stations; routers; telecommunication
infrastructure/switches; wired, optical and wireless communication
devices; cell processor devices; printers; power supplies;
displays; optical devices; instrumentation systems including
hand-held systems; military electronics; etc. The concepts will be
described and illustrated herein as applied to a desktop-sized
computer. However, it is to be realized that the concepts could be
used on other electronic devices as well.
[0045] FIGS. 2, 3A and 3B illustrate one embodiment of a
desktop-sized computer 20 employing a liquid submersion cooling
system 22. All active components are illustrated submerged in a
tank of dielectric liquid. This system uses a dielectric cooling
liquid in direct contact with the electronically and thermally
active components of a computer system. Dielectric liquids that can
be used in this type of immersive cooling system include, but are
not limited to: [0046] Engineered fluids like 3M.TM. Novec.TM.
[0047] Mineral oil [0048] Silicone oil [0049] Natural ester-based
oils, including soybean-based oils [0050] Synthetic ester-based
oils Many of these dielectric fluids also have the ability to
extinguish fires on computer components. By submerging computer
components in a dielectric, fire-retardant fluid, the chance of a
fire starting due to computer component failure is minimized.
[0051] Initial testing has involved the dielectric liquid 3M.TM.
Novec.TM.. However, other dielectric liquids, like mineral oil and
ester-based oils, may be used. Other dielectric liquids that have a
higher boiling temperature along with greater thermal transfer
capability can be employed. These cooling liquids need not change
state if they have a high enough thermal transfer capability to
handle the amount of heat being generated by components contained
in the system.
[0052] The lid 2 of the case 1 will attach to the connector side of
the computer motherboard 30, shown in FIGS. 7, 8A and 8B, allowing
motherboard input/output (IO) connections, daughter card 4 IO and
power to be passed in and out of the system. Components such as
daughter cards 4, additional processors 6, power supply card 5, and
memory cards 8 can be added to the system by opening the tank lid 2
and lifting the attached electronics out of the case 1. In
addition, a hard drive 11 can be disposed in the case 1, with an
air line 10 connected to the hard drive breather hole leading from
the hard drive to the exterior of the case 1.
[0053] At least one pump 13 will pump warm liquid from the top of
the case 1 and pass it through surrounding heat exchangers 3. The
pump 13 may be submersed in the liquid as shown in FIGS. 3B and 10,
or external to the case 1. Using two external pumps 13 with
quick-release hose attachments would allow hot-swapping of a failed
pump while the other pump maintains system circulation. Using one
external pump 13 with quick-release hose attachments would allow
the change-out of a failed pump with only a brief system
downtime.
[0054] The heat exchangers 3 can act as the outside surface and
supporting structure of the computer case 1. The majority of the
case wall may act as a radiator surface. Unlike current Advanced
Technology Extended (ATX) or Balanced Technology Extended (BTX)
cases that push air through fans from the front of the case to the
back, the disclosed system will take cold air from the base of the
case and, aided by natural convection, pull more air up as intake
air is heated and rises. The walls of the heat exchangers 3 may be
tapered upward, like a cooling tower on a boiler. This tapering
will help accelerate convection currents, making it possible to
cool the system without the use of air-moving devices, such as
fans.
[0055] As shown in FIG. 3A and 3B, the case 1 is large enough to
contain all of the active computer components that require cooling.
It may also be necessary to leave space for liquid return lines 48
with nozzles over critical components that require cooling. Nozzles
may be incorporated to direct the flow of the return liquid at
specific, high-temperature areas like the CPUs.
[0056] As shown in FIGS. 5A-C, 6 and 9, the lid 2 not only provides
a liquid- and gas-tight seal for the case 1, but it also contains a
pass-through connector 7 that allows external component IO, storage
IO and power to pass into and out of the case 1, to and from the
computer motherboard 30 and its components. The lid 2 will have a
gasket that will seal the case 1. The lid 2 may also contain a fill
port 32 for filling the case 1 with coolant.
[0057] As shown in FIGS. 7, 8A and 8B, the motherboard 30 is
essentially functionally the same as in current ATX or BTX
specification boards, with the exception being that it does not
have the same IO and power connectors. Instead, the top edge of the
board is lined with a series of conductive pads 34 that are
contacts for engaging the pass-through connector 7 that is part of
the lid 2. Multiple motherboards or other circuit boards may be
employed to allow stacking of extra processors 6 or other
components for additional computing power or to allow for multiple
computers within a single tank enclosure. This cooling system would
allow for numerous computer systems to be cooled in a single tank
or individual tanks which may be interconnected to create a server
or workstation rack system.
[0058] As shown in FIGS. 8A and 8B, the daughter cards 4 connect to
the motherboard 30 as they do with current ATX or BTX specification
boards. Daughter cards 4 can include video cards and other PCI or
PCIE cards that require IO pass-through to the outside of the case
1. These daughter cards 4 will require liquid- and gas-tight
gaskets in order to allow external IO connections.
[0059] Unlike ATX or BTX designs, the power supply 5 may also be a
daughter card 4, with no power supply to motherboard wiring
required. The power supply may also be directly integrated into the
motherboard. External alternating current (AC) connections would be
made through a pass-through connector into the liquid-filled tank
with a liquid and gas-tight gasket.
[0060] As shown in FIG. 9, the pass-through connector 7 is
integrated into the lid 2 in such a way that it creates a liquid-
and gas-tight electrical conduit for IO and power connectivity. It
attaches to the motherboard 30 on the inside of the case 1 and
leads to a connector break-out 36 on the outside of the tank 1.
[0061] The pump 13 (or pumps) is either internally-mounted within
the case 1, submersed in the liquid as shown in FIG. 10, or
externally mounted. The pump is used to circulate warm coolant from
inside the tank 1 to outside of the tank I within the heat
exchangers 3. Liquid may also be circulated through external hard
drive cooling plates as well. The pump 13 can be wired such that it
can be turned on to circulate liquid even if the computer is off Or
the pump 13 can be wired to turn on only when the computer is on.
After the computer is shut off, there is more than sufficient
thermal capacity in the liquid within the case 1 to remove residual
heat from the submerged components. This would ensure that there is
no post-shut down thermal damage. Also, if a flow sensor or pump
monitor indicates that flow of coolant has stopped or has slowed
below a minimum required rate, a controlled shutdown of the
computer could be completed well before any damage is done to the
submerged components. This embodiment avoids the possibility of a
fan failure, resulting in catastrophic failure of a computer that
relies on air cooling.
[0062] As shown in FIG. 10, the pump 13 is illustrated in the lower
left corner of the case 1. Warm coolant is pumped from the top of
the tank 1 to outside of the tank 1 into the heat exchangers 3. The
pump(s) 13 may alternatively be attached to the lid 2 of the
computer. This would allow for direct intake of fluids from the
warmest region of the tank 1 and make maintenance and replacement
of warn-out pumps much easier.
[0063] As shown in FIGS. 11A and 11B, the hard drives or other
internal storage systems 11 can also be submerged. In the case of
current platter-based, mechanical storage systems that require
breather holes, the air line 10 could be fixed over the breather
hole, allowing an open-air connection to the outside of the tank 1.
The rest of the drive 11 would be sealed as to be gas and liquid
impermeable.
[0064] The processors 6 mount to the motherboard 30 via normal,
vender-specified sockets. Testing has shown that no heat sinks or
other appliances need to be attached to the processors 6 in order
to cool them sufficiently for normal, vendor-specified
temperatures. However, if lower operating temperatures or a higher
level of heat transfer is required for processor 6 over-clocking,
heat sinks, which greatly increase the exposed surface area of heat
conduction from the processor(s) 6, may be employed.
[0065] As shown in FIGS. 12A and 12B, the heat exchangers 3 or heat
exchanger surfaces may serve as the external shell or case of the
computer 20. When warm cooling liquid is pumped from within the
case 1 to the heat exchangers 3, the liquid is cooled to ambient
temperature. Cooling of liquids utilizing a heat exchanger 3 can be
accomplished by one of several means: [0066] A compressor, as is
the case with typical refrigeration systems [0067] Peltier effect
cooling [0068] Active air cooling of the radiator surface using a
fan or other air-moving mechanism [0069] Passive cooling by
exposing as large of a thermally conductive heat exchange surface
as possible to lower ambient temperatures
[0070] As shown in FIGS. 12A, 12B, 13A and 13B, the heat exchangers
3 arc designed such that they angle inward and upward, creating a
cooling tower effect, as seen on industrial boilers. This taper
will serve to create thermal conduction that draws more cool air
from near the bottom of the case 1 and allows it to migrate
naturally upward and out of the top of the heat exchangers 3.
Cool-air inlet ports (not shown) at the base of the heat exchangers
can be covered with filter material in order to keep dust and other
foreign matter out of the heat exchangers, while allowing air to
enter. A fan or multiple fans may be used to aid in the upward flow
of air through the cooling system.
[0071] As the cooled liquid is pumped back into the case 1, it may
be sent through tubes or other deflection/routing means to injector
head assemblies that serve to accelerate coolant across the most
thermally active components. This accelerated liquid would help to
create turbulent flow of coolant across the heated surface. This
turbulent flow would break down natural laminate flow, which is
poor at conducting heat through a liquid because only the first few
molecules of liquid that are in contact with the heated surface can
actually take heat energy away from the heated surface.
[0072] The computer 20 can also include external, removable storage
drives such as CD, DVD, floppy and flash drives (not illustrated).
In addition, external IO, power button and other human interface
controls (not shown) would attach to the pass-through connector 7
and be mounted on a rigid circuit board or flex circuit.
[0073] FIG. 12B illustrates one possible flow path of liquid
through the multiple heat exchangers 3: [0074] 1. Liquid is pumped
out of the case 1 from the warm upper area of the case 1 by the
pump 13 through an inlet pipe 40 and out a discharge pipe 42 (see
FIG. 10); the discharge pipe 42 is connected to an inlet 44 of the
heat exchanger 3. [0075] 2. Liquid flows through and is cooled by
the heat exchanger 3 that is also one side wall of the computer
case. [0076] 3. A connection 46 allows liquid to pass through from
the heat exchanger 3 on one side of the case 1 to the heat
exchanger 3 on the other side of the computer case 1. [0077] 4.
Coolant flows through the heat exchanger 3 on the other side of the
case 1. [0078] 5. Cooling liquid flows from the heat exchanger
through a passageway 48 back into the case 1 near the bottom
thereof where it is warmed by the heat-generating electronics and
components and rises back to the top of the case 1 and the cycle
begins again.
[0079] Alternatively, a single heat exchanger 3 as shown in FIGS.
13A and 13B can be used in the cooling system through the following
steps. [0080] 1. Liquid is pumped out of the case 1 from the warm
upper area of the tank as in the embodiment in FIG. 12B. [0081] 2.
Liquid flows through and is cooled by the heat exchanger 3 that is
on one side wall of the computer case 1. [0082] 3. Cooling liquid
flows back to the bottom area of the tank 1 through a passageway 50
where it is warmed and rises back to the top of the case 1, and the
cycle begins again.
[0083] The computer system can be cooled via active or passive
convection cooling, as shown in FIG. 14. Rather than forcing air
from the front of the ease to the back of the case, as seen in
conventional designs, air is allowed to travel vertically. Heat
rises, and the cooling system 22 design takes advantage of this, as
described in the following steps. [0084] 1. Cool air from
underneath the computer is drawn upward as shown by arrows 52.
[0085] 2. The heat exchangers 3 are designed to allow the cool air
to flow upward between the heat exchangers and the outside of the
case 1. As heat is dissipated from the coolant inside the heat
exchangers 3, the cooler air around the heat exchangers 3 is heated
and rises. [0086] 3. The air flows through the heat exchangers 3
and is expelled at the sides and top of the system. This rising air
helps to pull more cool air into the system, much like a cooling
tower for a boiler.
[0087] Air flow may be aided by the use of an air-moving device or
devices such as one or more fans mounted on the top or bottom of
the cooling stack. However, for some applications only passive,
convection-induced air flow may be required.
[0088] FIGS. 15-16 illustrate a prototype computer 80 that
incorporates the liquid submersion cooling system 22. Due to the
clear case, the video boards and pump are visible in the case and
the heat exchangers are visible, mounted on the sides of the
case.
[0089] FIGS. 17-19 illustrate another embodiment of a personal
computer 100 employing an alternative liquid submersion cooling
system 102. The computer 100 includes a case 104 that has a
liquid-tight interior space 106 (FIG. 20) designed to be leak-proof
so that it can be filled with a coolant liquid. As used herein, the
word "case" is meant to include a housing, an enclosure, and the
like. In the illustrated embodiment, the side wall 107 of the case
defines at least one side of the interior space 106, and a portion
109 of the side wall 107 is made of translucent, preferably
transparent, material to allow viewing inside the space 106. The
material used for the portion 109 can be any material suitable for
forming a leak-proof container and, if viewing of the internal
computer components is desired, the material should be translucent
or transparent. An example of a suitable material is a
polycarbonate.
[0090] The case 104 also includes non-liquid tight space 111 next
to the liquid-tight interior space 106 in which components of the
computer 100 and the cooling system 102 are disposed as described
below.
[0091] With reference to FIGS. 17 and 20, the case 104 includes a
lid 108 that closes the top of the case 104, but which can be
removed to permit access to the spaces 106, 111. The lid 108
includes a seal 113 (shown in FIGS. 21 and 22) for forming a
liquid-tight seal with the interior space 106 of the case when the
lid 108 is in position closing the case. In addition, the lid 108
includes a handle 110 that facilitates grasping of the lid 108 and
lifting of any internal computer components connected thereto out
of the interior space 106. The lid 108 also includes a pass-through
connector 112 (partially visible in FIG. 22), similar in function
to the pass-through connector 7, to which a motherboard 114
assembly is connected, and which permits pass-through connections
such as USB ports, video card connections, etc., through the lid
108 to the inside of the space 106 and to the outside of the space
106.
[0092] For safety, an AC current cut-off mechanism 115 is also
provided, as shown in FIGS. 31A-C, such that when the lid 108 is
opened, electrical power in the computer is shut off, preventing
operation of any electrical components. For example, the mechanism
115 may be accomplished by routing AC power through a bridge board
400 that is contained in, or otherwise connected to, the lid 108.
The board 400 is connected to the motherboard assembly 114
comprised of a motherboard 302 and a support 300 member.
[0093] The board 400 includes an AC power socket 402 for receiving
AC power. A neutral line 404 and a ground line 406 leads from the
power socket 402 to a pass-through connector 112 leading to the
interior space 106. In addition, a hot or live wire 408 leads from
the socket 402 to a second pass-through connector 112 leading to
the space 111, passes under the board 400 and back to the top of
the board 400 to a return portion 410 that connects to the pass
through connector 112 to pass AC power into the interior space
106.
[0094] An external board 412, illustrated in FIG. 31C, is fixed in
the space 111. The board 402 includes a unshaped connector 414 at
the top thereof, one end of which connects to the hot wire 408 and
the other end of which connects to the return portion 410 when the
lid 108 is in place.
[0095] When the case is opened by removing the lid 108, the hot
wire 408 becomes disengaged from the connector 414 on the external
board 412, opening the electrical circuit and disconnecting AC
power from the interior space. The current cut-off mechanism 115
may also be accomplished by routing AC power through two pins on
the bridge board 400. These pins would be shorted, passing current
back to the external board 412. When the case is opened, the bridge
board 400 becomes disengaged from the connector 414 on the external
board 412.
[0096] The lid 108 also includes an opening 116 through which
liquid can be added into the space 106. The opening 116 is closed
by a removable cap which is removed when liquid is to be added. The
lid 108 can also include a lock mechanism (not shown) that locks
the lid in place.
[0097] With reference to FIG. 20, the case 104 can include a drain
valve 118 (shown schematically) that can be opened in order to
drain liquid from the case. The valve 118 can be any type of valve
that can be opened and closed, preferably manually, for draining
the case. The valve 118 is illustrated as being positioned at the
bottom of the interior space at the bottom of the case 104.
However, the valve can be positioned at any other suitable location
on the case. The front portion of the case 104 can have a touch
screen display that allows users to run the computer 100 from the
front without plugging in a monitor.
[0098] The motherboard assembly 114 acts as a support for many of
the internal components of the computer 100. The motherboard
assembly 114 is removable and disposed in the interior space 106 to
permit the motherboard assembly to be lifted from the case when the
lid 108 is lifted upward. With reference to FIGS. 20-22, the
motherboard assembly 114 includes a support member 300 on which is
disposed a motherboard 302 that supports the submerged
components.
[0099] The motherboard assembly 114 is fixed to the lid 108 via
flanges 122 at the top end of the motherboard 114, shown in FIG.
24, that connect to the pass-through connector 112. In addition, a
pair of tabs 123 that are fixed to the support member 300 are
connected to the lid 108.
[0100] An exemplary layout of the motherboard components is
illustrated in FIG. 23. The layout is designed to render the
motherboard nearly or completely 302 wire-free and facilitate
movement of cooling liquid in the interior space 106. The
motherboard 302 is illustrated as having mounted thereto four CPUs
and/or GPUs 124, video/motherboard memory cards 126, memory cards
127, power supply 128, and controller chips 130. These components
are laid out relative to each other to define a number of vertical
and horizontal liquid flow channels that aid in the flow of liquid.
For example, vertical channels include channel 132A between the
CPUs/ GPUs 124, channels 132B between the controller chips 130, and
channels 132C between the CPUs/GPUs and the memory cards 126, 127.
Horizontal channels include, for example, channel 134A between the
CPUs/GPUs, channel 134B between the CPUs/GPUs and the controller
chips 130, and channel 134C between the CPUs/GPUs and the power
supply 128. A plurality of sets of light-emitting diodes (LEDs)
136, that can produce a desired color/wavelength of light, such as
ultraviolet can also be mounted to the motherboard 114 at dispersed
locations. When illuminated, the LEDs 136 give the liquid in the
interior space 106 a luminescent glow.
[0101] To help dissipate heat, heat sinks can be affixed to some or
all of the heat-generating components on the motherboard 302. The
use of heat sinks will depend on the amount of heat generated by a
particular component and whether it is determined that additional
heat dissipation than that provided by direct contact with the
liquid is necessary for a particular component.
[0102] As shown in FIGS. 20-23, heat sinks 140 are shown attached
to the CPUs/GPUs 124 and the controller chips 130. The heat sinks
140 each comprise a plurality of elongated fins 142 that extend
from a base plate 144 fixed to the component. The fins 142 and
plate 144 conduct heat away from the component. In addition, the
fins 142 define flow channels therebetween that allow the cooling
liquid to flow through and past the plurality of fins to transfer
heat to the liquid.
[0103] Heat sinks 150 are also attached to the memory cards 126,
127 and the power supply 128. The heat sinks 150 are similar to the
beat sinks 140, including fins 152 connected to a base plate 154
fixed to the component. However, the fins 152 are short, having an
axial length significantly less than the fins 142. Nonetheless, the
fins 152 define flow channels therebetween which allow the cooling
liquid to flow through and past the plurality of fins to transfer
heat to the liquid.
[0104] As described above, the motherboard assembly 114 is
removable and disposed in the interior space 106 to permit the
motherboard assembly to be lifted from the space when the lid 108
is lifted upward. With reference to FIG. 24, the interior space 106
of the case 104 includes a pair of channels 160 at opposite ends of
the walls that define the interior space. Each channel 160 extends
from the top of the walls to the bottom, and are continuous from
top to bottom. As shown in FIGS. 22 and 24, the side edges of the
motherboard assembly are provided with slides 162 that are sized
and configured to slide within the channels 160. The channels 160
and the slides 162 help guide the motherboard assembly 114 when it
is lifted upward from the case and when it is lowered back into the
interior space.
[0105] With reference to FIGS. 21-24, one or more slide locking
mechanisms 170 can be provided to retain the motherboard assembly
114 at a raised position outside the interior space 106. Two slide
locking mechanisms 170 are illustrated. However, a single slide
locking mechanism could be used if found sufficient to retain the
motherboard assembly at the raised position. By keeping the
motherboard assembly raised, maintenance and/or replacement of
motherboard components is facilitated, while also allowing liquid
to drain down into the interior space 106 when the assembly 114 is
lifted upward.
[0106] The slide locking mechanisms 170 can have a number of
configurations. The illustrated embodiment is shown to include a
stop member 172 that forms part of the slide 162. The stop member
172 is pivotally connected to the motherboard assembly so that it
30 can rotate between the position shown in FIGS. 21-23 and the
position shown in FIG. 24. The stop member 172 is biased by a
spring (not shown) to bias the stop member in a counterclockwise
direction (when viewing FIG. 21) so that when the motherboard
assembly is lifted upward, the stop member(s) automatically rotate
to the position shown in FIG. 24 when the stop members 172 clear
the channels 160.
[0107] At the position shown in FIG. 24, the stop member 172 is
prevented from further rotation in the counterclockwise direction
to prevent the motherboard assembly from falling back down into the
interior space 106 due to interference between the stop member(s)
172 and the structure forming the channels 160. To release the
slide locking mechanisms 170, the motherboard assembly is lifted
further upward, and the stop member(s) manually rotated in a
clockwise direction to the position shown in FIGS. 21-23. The
assembly is then lowered down into the case.
[0108] With reference to FIGS. 17 and 20, the submersion cooling
system 102 includes a heat exchanger 180 mounted in the space 111
within the case 104, a pump 210 mounted on the motherboard 302
inside the interior space 106, and a dielectric cooling liquid
within the interior space 106. The interior space should contain
enough dielectric cooling liquid to submerge the components that
one wishes to be submerged. For example, the cooling liquid may
substantially fill the interior space 106, whereby all
heat-generating components on the motherboard are submerged. The
cooling system 102 is designed to direct heated dielectric liquid
from inside the space 106 and into the heat exchanger 180 outside
the space 106 where the liquid is cooled. The cooled liquid is then
returned to the space 106.
[0109] The heat exchanger 180 is positioned outside of the space
and substantially forms an outer wall of the computer 100 as shown
in FIG. 18. The heat exchanger 180 is configured to allow passage
therethrough of the liquid for cooling. In the illustrated
embodiment, the heat exchanger 180 is of a size to form
substantially one wall of the case 104. With reference to FIG. 26,
the heat exchanger 180 includes an inlet 182 through which cooling
liquid enters, an outlet 184 through which cooling liquid exits,
and at least one flow path for cooling liquid through the heat
exchanger extending from the inlet 182 to the outlet 184.
[0110] The heat exchanger 180 can take on a number of different
configurations, as long as it is able to cool the liquid down to an
acceptable temperature prior to being fed back into the space 106.
An exemplary configuration of the heat exchanger 180 is shown in
FIGS. 26 and 27. In this embodiment, the heat exchanger 180
comprises a plurality of identical plates 186 that are connected
together. Each plate 186 includes a hole 188, 190 at each end that
during use form plenums that receive the dielectric liquid. The
plate 186 also includes a first plurality of holes 192 defined by
bosses that extend in one direction, and a second plurality of
holes 194 defined by bosses that extend in the opposite direction.
The holes 188, 190 are also defined by bosses that extend in the
same direction as the bosses defining the holes 192. In addition, a
central portion 196 of the plate 186 is bulged in the direction of
the bosses of the holes 188, 190, 192, so that the opposite side of
the plate 186 is recessed 198 below a surrounding rim 200.
[0111] To form the heat exchanger 180, a first plate 186A is
flipped over as shown in FIG. 27, and the two plates 186A, 186B
then secured together such as by soldering along the rim 200. The
two holes 188 are aligned at the top, and the two holes 190 are
aligned at the bottom. In addition, the bosses that define the
holes 194 engage with each other to form a number of air passages
between the two plates 186A, 186B. The recesses 198 allow liquid to
flow downward from the holes 188, past the engaged bosses of the
holes 194, and down to the holes 190.
[0112] A third plate 186 is then connected to one of the plates
186A, 186B, with the third plate being flipped over relative to the
plate to which it is connected. The bosses that define the holes
188, 190 will engage each other, as will the bosses that define the
holes 192. This will create a series of air flow paths 202 on the
outside of the heat exchanger as shown in FIG. 26. This process of
adding plates 186 is repeated to create the size of heat exchanger
needed. For the two plates at opposite ends of the heat exchanger
180, the holes 192, 194 will be closed off to prevent escape of
liquid. In addition, an inlet fitting 204 defining the inlet 182
will be connected to the boss defining the opening 188, while an
outlet fitting 206 defining the outlet 184 will be connected to the
boss defining the opening 190. At the opposite end of the heat
exchanger, the openings 188, 190 are closed by suitable caps
208.
[0113] In use of the heat exchanger 180, liquid to be cooled flows
into the inlet 182 and into the plenum at the top of the heat
exchanger defined by the holes 188. The liquid is able to flow
downward in the recesses 198 past the bosses of the holes 194. As
it does, the liquid transfers heat to the bosses. At the same time,
air can flow into the aligned bosses of the holes 194 to pick up
heat. Air also flows into the flow paths 202 for additional heat
exchange with the bulged central portion 196. The cooled liquid
collects in the plenum defined by the aligned holes 190, and is
pumped through the outlet 184 and back into the space 106 by the
pump 210.
[0114] Referring to FIGS. 20, 22 and 23, the pump 210 is mounted on
the motherboard 302 and in use is submerged in the dielectric
liquid. The pump 210 is sized to be able to circulate liquid to
outside the space, through the heat exchanger, and back into the
space. The pump 210 is illustrated as a centrifugal pump having an
inlet 212 and an outlet 214. The inlet 212 receives liquid
therethrough from the space 106, and pumps it through the outlet
214 connected to an outlet port 218 formed on the lid 108. The
outlet port 218 extends through the lid 108 and is fluidly
connected to the heat exchanger inlet 182 by suitable tubing. The
heat exchanger outlet 184 is fluidly connected by suitable tubing
to an inlet port 222 formed through the lid to direct liquid back
into the space 106.
[0115] In areas where there is significant heat, direct impingement
cooling can be used to provide localized cooling. In particular, as
shown in FIGS. 20, 22, and 23, a spray bar assembly 230 is
connected to the inlet port 222. The spray bar assembly 230
includes a central passageway 231 extending along the vertical
channel 132A, and plurality of branches or vents 232 that extend
along the horizontal channels 134A-C (and at the bottom of the
space 106). The branches 232 include holes 234 (FIG. 20) to direct
cooled liquid directly onto the components 124, 126, 127, 128, 130.
The holes 234 are in the top of the branches 232 to direct liquid
upwardly. However, holes could also be provided at the bottom of
the branches to directed liquid downwardly onto the components.
[0116] An air-moving device can be provided to create a flow of air
past the heat exchanger. A number of different air-moving devices
can be used, for example, a fan or an ionization device. The
drawings illustrate the use of a fan 240 to create air movement
past the heat exchanger 180. The fan 240 is best seen in FIGS. 20,
25, and 28. The fan 240 is positioned at the bottom of the computer
100 at the base of the heat exchanger 180. In the illustrated
embodiment, the fan is a squirrel-cage type fan with an air outlet
241 that extends substantially across the entire length of the heat
exchanger in order to create air flow across the entire heat
exchanger. An air filter 242 is located in front of the inlet of
the fan 240 in order to filter the air. The air filter 242 can be
any suitable type of air filter, for example, a high-efficiency
particulate air (HEPA) filter. The filter 242 is mounted so as it
is able to slide and be removable from the case 104 by pulling on a
handle 243. This permits the filter 242 to be cleaned or
replaceable with a replacement filter. Air is drawn into the filter
and the fan via a series of air vents 244 (FIG. 18) on the side of
the computer.
[0117] The computer 100 can also include additional features, such
as a drive mechanism 250 external to the case 104. The drive
mechanism 250 can be a DVD drive, a floppy drive, a CD drive, a
Blu-ray drive, HD drive, and the like. In addition, one or more
hard drives 252 are accessible from the opposite side of the case
104. The hard drives 252 can be mounted so as to permit easy
replacement with replacement hard drives.
[0118] In some embodiments, the hard drive 252 may be disposed
within the interior space 106 of the case, submerged in the
dielectric liquid. In these embodiments, it is necessary to
equalize air pressure within the hard drive and the exterior of the
space 106. FIGS. 29 and 30A-C illustrate a snorkel attachment 260
that can be connected to a breather hole 261 (see FIG. 30A) on a
hard drive to aid in achieving the pressure equilibrium. The
snorkel attachment 260 includes a circular cap 262 that is designed
to fit around the breather hole 261 (see FIG. 30B) and form a
liquid tight seal with the hard drive 252 to prevent entry of
liquid. A fitting 264 extends from the cap 262, and a breather
conduit 266 connects to the fitting 264. The breather conduit 266
can be directed to the outside of the space 106, or the conduit 266
can connect to a fitting extending through the lid 108. The snorkel
attachment 260 permits achievement of pressure equilibrium between
the hard drive and outside air pressure, allowing the hard drive to
function properly while submerged in the dielectric liquid.
[0119] The dielectric liquid that is used in the computer 100 can
be any of the dielectric liquids discussed above. In addition, a
soy-based dielectric liquid can be used. If desired, a colorant
material can be added to the dielectric liquid to make the liquid a
particular color. Because the portion 109 of the side wall 107 is
clear, adding a colorant to the liquid will change the visual
impact of the computer.
* * * * *