U.S. patent application number 10/280923 was filed with the patent office on 2004-04-29 for field replaceable packaged refrigeration module with capillary pumped loop for cooling electronic components.
This patent application is currently assigned to Sun Microsystems, Inc.. Invention is credited to Monfarad, Ali Heydari.
Application Number | 20040079100 10/280923 |
Document ID | / |
Family ID | 32107055 |
Filed Date | 2004-04-29 |
United States Patent
Application |
20040079100 |
Kind Code |
A1 |
Monfarad, Ali Heydari |
April 29, 2004 |
Field replaceable packaged refrigeration module with capillary
pumped loop for cooling electronic components
Abstract
A field and/or customer replaceable packaged refrigeration
module with capillary pumped loop is suitable for use in standard
electronic component environments. The field replaceable packaged
refrigeration module portion is self-contained and is specifically
designed to have physical dimensions similar to those of a standard
air-based cooling system, such as a fined heat sink or heat pipe.
The field replaceable packaged refrigeration module is coupled to a
capillary pumped loop and serves to lower the base temperature of
the capillary pumped loop sub-system, thereby allowing intermittent
operation of the field replaceable packaged refrigeration module
with the capillary pumped loop sub-system.
Inventors: |
Monfarad, Ali Heydari;
(Milpitas, CA) |
Correspondence
Address: |
Philip J. McKay
Gunnison, McKay & Hodgson, L.L.P.
Suite 220
1900 Garden Road
Monterey
CA
93940
US
|
Assignee: |
Sun Microsystems, Inc.
|
Family ID: |
32107055 |
Appl. No.: |
10/280923 |
Filed: |
October 25, 2002 |
Current U.S.
Class: |
62/259.2 ;
257/E23.088; 62/498 |
Current CPC
Class: |
F25B 1/00 20130101; F25B
23/006 20130101; F25B 2400/21 20130101; H01L 2924/0002 20130101;
H01L 2924/0002 20130101; F25B 2500/17 20130101; F25B 1/02 20130101;
F25B 1/04 20130101; F25B 2400/073 20130101; F25B 39/022 20130101;
F25B 2500/01 20130101; H01L 23/427 20130101; F25B 25/005 20130101;
H01L 2924/00 20130101; F04B 35/045 20130101 |
Class at
Publication: |
062/259.2 ;
062/498 |
International
Class: |
F25D 023/12; F25B
001/00 |
Claims
What is claimed is:
1. A packaged refrigeration module with capillary pumped loop for
cooling electronic components, said packaged refrigeration module
with capillary pumped loop comprising: a packaged refrigeration
module, said packaged refrigeration module comprising: a packaged
refrigeration module housing; refrigerant; a compressor; a
condenser; an evaporator; and an expansion device; wherein, said
compressor, said condenser, said evaporator and said expansion
device are coupled together in a refrigeration loop within said
packaged refrigeration module housing and said refrigerant is
contained within said refrigeration loop such that said packaged
refrigeration module is a self-contained module; and a capillary
pumped loop, said capillary pumped loop being operatively coupled
to said packaged refrigeration module refrigeration loop.
2. The packaged refrigeration module with capillary pumped loop of
claim 1; wherein, said packaged refrigeration module has a width of
approximately 4 inches, a length of approximately 5 inches and a
height of approximately 1.75 inches.
3. The packaged refrigeration module with capillary pumped loop of
claim 1; wherein, said compressor is a single piston linear
compressor.
4. The packaged refrigeration module with capillary pumped loop of
claim 1; wherein, said compressor is a dual-piston linear
compressor.
5. The packaged refrigeration module with capillary pumped loop of
claim 1; wherein, said compressor is a multi-piston linear
compressor.
6. The packaged refrigeration module with capillary pumped loop of
claim 1; wherein, said compressor is a rotary compressor.
7. The packaged refrigeration module with capillary pumped loop of
claim 1; wherein, said compressor is a reciprocating
compressor.
8. The packaged refrigeration module with capillary pumped loop of
claim 1; wherein, said compressor is a rolling piston
compressor.
9. The packaged refrigeration module with capillary pumped loop of
claim 1; wherein, said compressor is a rotary vane compressor.
10. The packaged refrigeration module with capillary pumped loop of
claim 1; wherein, said compressor is a screw compressor.
11. The packaged refrigeration module with capillary pumped loop of
claim 1; wherein, said compressor is a swash-plate compressor.
12. The packaged refrigeration module with capillary pumped loop of
claim 1; wherein, said compressor is a scroll compressor.
13. A circuit board, said circuit board comprising: at least one
electronic component; a packaged refrigeration module for cooling
said electronic component, said packaged refrigeration module
comprising: a packaged refrigeration module housing; refrigerant; a
compressor; a condenser; an evaporator; an expansion device;
wherein, said compressor, said condenser, said evaporator and said
expansion device are coupled together in a refrigeration loop
within said packaged refrigeration module housing and said
refrigerant is contained within said refrigeration loop such that
said packaged refrigeration module is a self-contained module; and
a capillary pumped loop, said capillary pumped loop being
operatively coupled to said packaged refrigeration module
refrigeration loop; wherein, said capillary pumped loop includes a
capillary pumped loop reservoir, said capillary pumped loop
evaporator reservoir being thermally coupled to said packaged
refrigeration module evaporator; further wherein, said packaged
refrigeration module evaporator is mounted directly over a first
surface of said electronic component.
14. The circuit board of claim 13; wherein, said packaged
refrigeration module has a width of approximately 4 inches, a
length of approximately 5 inches and a height of approximately 1.75
inches
15. The circuit board of claim 13; wherein, said compressor is a
single piston linear compressor.
16. The circuit board of claim 13; wherein, said compressor is a
dual-piston linear compressor.
17. The circuit board of claim 13; wherein, said compressor is a
multi-piston linear compressor.
18. The circuit board of claim 13; wherein, said compressor is a
rotary compressor.
19. The circuit board of claim 13; wherein, said compressor is a
reciprocating compressor.
20. The circuit board of claim 13; wherein, said compressor is a
rolling piston compressor.
21. The circuit board of claim 13; wherein, said compressor is a
rotary vane compressor.
22. The circuit board of claim 13; wherein, said compressor is a
screw compressor.
23. The circuit board of claim 13; wherein, said compressor is a
swash-plate compressor.
24. The circuit board of claim 13; wherein, said compressor is a
scroll compressor.
25. The circuit board of claim 13; wherein, said electronic
component is an integrated circuit.
26. The circuit board of claim 13; wherein, said electronic
component is a microprocessor.
27. An electronic system, said electronic system comprising: a rack
unit, said rack unit comprising: at least one electronic component;
a packaged refrigeration module, said packaged refrigeration module
comprising: a packaged refrigeration module housing; refrigerant; a
compressor; a condenser; an evaporator; an expansion device;
wherein, said compressor, said condenser, and said expansion device
are coupled together in a refrigeration loop within said packaged
refrigeration module housing and said refrigerant is contained
within said refrigeration loop such that said packaged
refrigeration module is a self-contained module; and a capillary
pumped loop, said capillary pumped loop being operatively coupled
to said packaged refrigeration module refrigeration loop; wherein,
said capillary pumped loop includes a capillary pumped loop
reservoir, said capillary pumped loop evaporator reservoir being
thermally coupled to said packaged refrigeration module evaporator;
further wherein, said packaged refrigeration module evaporator is
mounted directly over a first surface of said electronic
component.
28. The electronic system of claim 27; wherein, said packaged
refrigeration module has a width of approximately 4 inches, a
length of approximately 5 inches and a height of approximately 1.75
inches.
29. The electronic system of claim 27; wherein, said compressor is
a single piston linear compressor.
30. The electronic system of claim 27; wherein, said compressor is
a dual-piston linear compressor.
31. The electronic system of claim 27; wherein, said compressor is
a multi-piston linear compressor.
32. The electronic system of claim 27; wherein, said compressor is
a rotary compressor.
33. The electronic system of claim 27; wherein, said compressor is
a reciprocating compressor.
34. The electronic system of claim 27; wherein, said compressor is
a rolling piston compressor.
35. The electronic system of claim 27; wherein, said compressor is
a rotary vane compressor.
36. The electronic system of claim 27; wherein, said compressor is
a screw compressor.
37. The electronic system of claim 27; wherein, said compressor is
a swash-plate compressor.
38. The electronic system of claim 27; wherein, said compressor is
a scroll compressor.
39. The electronic system of claim 27; wherein, said electronic
component is an integrated circuit.
40. The electronic system of claim 27; wherein, said electronic
component is a microprocessor.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a refrigeration system for
cooling electrical components. More particularly, the invention
relates to a field and/or customer replaceable refrigeration module
coupled to a capillary pumped loop that is suitable for use in
standard electronic component environments.
BACKGROUND OF THE INVENTION
[0002] Electronic components, such as microprocessors and other
various integrated circuits, have advanced in at least two
significant ways. First, feature sizes have moved into the
sub-micron range thereby allowing larger numbers of transistors to
be formed on a given surface area. This in turn has resulted in
greater device and circuit density on the individual chips. Second,
in part due to the first advance discussed above, microprocessors
have increased dramatically in clock speed. At present
microprocessor speeds of 2.5 Gigahertz are coming to market and the
3 and 4 Gigahertz range is rapidly being approached.
[0003] As a result of the advances in device density and
microprocessor speed discussed above, heat dissipation, which has
always been a problem in the past, is rapidly becoming the limiting
factor in microprocessor performance. Consequently, heat
dissipation and cooling is now the foremost concern and the major
obstacle faced by system designers.
[0004] As noted, heat dissipation has long been recognized as a
serious problem limiting the performance of electronic components
and systems. In the past, the solutions to the heat dissipation
problem have been mostly limited to air-based cooling systems, with
only the most exotic military, scientific and custom electronic
systems employing the bulky and costly prior art liquid-based
cooling solutions.
[0005] In the prior art, air-based cooling systems, such as heat
sinks, cooling fins, heat pipes and fans, have been the systems of
choice for several reasons. First, the air-based cooling systems of
the prior art were modular and self-contained and were therefore
field replaceable with minimal effort using standard tools. Second,
the prior art air-based cooling systems attached directly to the
components that needed cooling and a discrete cooling unit could be
provided for each heat source. In addition, air-based cooling
systems were compact and simple in both operation and installation,
with minimal parts to fail or break and minimal added system
complexity. Therefore, prior art air-based cooling systems were
reliable. In addition, and probably most importantly, in the prior
art, air-based cooling systems could reasonably meet the cooling
needs of electronic devices and systems so there was little
motivation to move to the more complex and problematic liquid-based
systems. However, as noted above, due to the advances in
microprocessor speeds and device density, air-based cooling systems
alone will most likely not be a viable option for electronic device
cooling for the next generation of microprocessors.
[0006] As noted above, another possible prior art cooling system
that could potentially provide the level of cooling required by the
next generation of microprocessors is liquid-based cooling systems.
Prior art liquid-based cooling systems typically used a
refrigerant, such as R134A, that was circulated by a compressor. In
prior art liquid-based cooling systems the compressor was typically
a crankshaft reciprocating compressor or a rotary compressor
similar to those used in home refrigerators.
[0007] As noted above, prior art liquid-based cooling systems have
far more potential cooling capability than air-based systems.
However, in the prior art liquid-based cooling systems, the
crankshaft reciprocating or rotary compressors were typically, by
electronics industry standards, very large, on the order of tens of
inches in diameter, very heavy, on the order of pounds, and often
required more power to operate than the entire electronic system
they would be charged with cooling. In addition, the size and
design of prior art liquid-based cooling systems often required
that the major components of the prior art liquid-based cooling
system be centrally located, typically remote from the electronic
devices to be cooled, and that a complicated system of tubing or
"plumbing" be used to bring the cooling liquid into thermal contact
with the heat source, i.e., with the microprocessor or other
integrated circuit. Consequently, unlike prior art air-based
cooling systems, prior art liquid-based cooling systems were not
modular, were not self-contained, and often required special
expertise and tools for maintenance and operation. In addition,
unlike the prior art air-based cooling systems discussed above,
prior art liquid-based cooling systems did not attach directly to
the components that needed cooling and a discrete cooling unit
typically could not be provided for each heat source. Also, unlike
the prior art air-based cooling systems discussed above, prior art
liquid-based cooling systems were not compact and were not simple
in either operation or installation. Indeed, prior art liquid-based
cooling systems typically included numerous parts which could
potentially fail or break. This added complexity, and threat of
component failure, was particularly problematic with respect to the
associated plumbing discussed above because a failure of any of the
tubes could result in the introduction of liquid refrigerant into,
or onto, the electronic devices and could cause catastrophic system
failure.
[0008] In addition, prior art liquid-based cooling systems employed
compressors that typically were highly orientation dependent, i.e.,
they could not operate at angles of more than 30 or 40 degrees.
Consequently, prior art liquid based cooling systems were
particularly ill suited for the electronics industry that stresses
flexibility and often requires orientation independent
operation.
[0009] Given that, as discussed above, air-based cooling systems
have reached their operational limits when it comes to cooling
electronic components, there is a growing realization that some
other form of cooling system, such as liquid-based cooling systems
will need to be adopted by the electronics industry. However, as
discussed above, prior art liquid-based cooling systems are far
from ideal and, thus far, the industry has not adopted liquid-based
cooling in any meaningful way because the problems associated with
prior art liquid-based cooling systems are still thought to
outweigh the advantages these systems provide in terms of increased
cooling capacity.
[0010] What is needed is a cooling system that has the cooling
capacity and efficiency of a liquid-based cooling system yet has
the advantages of being modular, simple, and compact like air-based
cooling systems.
SUMMARY OF THE INVENTION
[0011] The present invention is directed to a field and/or customer
replaceable packaged refrigeration module with capillary pumped
loop that is suitable for use in standard electronic component
environments. According to the present invention, advances in
compressor technology are incorporated in a field replaceable
packaged refrigeration module that is coupled to a capillary pumped
loop cold plate evaporator to be used for cooling electronic
components. According to the invention, the field replaceable
packaged refrigeration module is self-contained and is specifically
designed to have physical dimensions similar to those of a standard
air-based cooling system, such as a fined heat sink or heat
pipe.
[0012] In one embodiment of the invention, the addition of the
field replaceable packaged refrigeration module to a capillary
pumped loop serves to create a system wherein the capillary pumped
loop is used to passively cool the heat source and the field
replaceable packaged refrigeration module is used to lower, or
maintain, the base temperature of the capillary pumped loop and/or
the associated capillary pumped loop working fluid reservoir.
Consequently, the field replaceable packaged refrigeration module
can be operated intermittently, on an as needed basis, to minimize
the power used by the system and to minimize the wear and tear of
the moving parts. The net result is the ability to manage and
remove heat from the heat source while saving energy since the
field replaceable packaged refrigeration module does not need to
operate at all times. Consequently, the use of a capillary pumped
loop with the field replaceable packaged refrigeration module
allows for more cooling capability and more efficient cooling,
lowered load on the field replaceable packaged refrigeration
module, and a lower failure rate of the cooling system and its
moving parts.
[0013] In addition, the addition of the field replaceable packaged
refrigeration module to a capillary pumped loop serves to create a
system wherein vibration transferred from the field replaceable
packaged refrigeration module to the often delicate electronic
component to be cooled is significantly reduced because, as
discussed above, the field replaceable packaged refrigeration
module can be operated intermittently, on an as needed basis.
[0014] The present invention can be utilized in existing electronic
systems and unlike prior art liquid-based cooling systems, the
various parts of the field replaceable packaged refrigeration
module with capillary pumped loop of the invention, including the
very minimal tubing, are largely self-contained in the field
replaceable packaged refrigeration module with capillary pumped
loop. Therefore a failure of any of the tubes would typically not
result in the introduction of liquid into, or onto, the electronic
devices and would not cause catastrophic system failure, as was the
risk with prior art liquid-based cooling systems.
[0015] The field replaceable packaged refrigeration module with
capillary pumped loop of the present invention is a modified
liquid-based cooling system and therefore provides the cooling
capacity of a prior art liquid-based cooling systems. However,
unlike prior art liquid-based cooling systems, the field
replaceable packaged refrigeration module with capillary pumped
loop of the invention is modular and largely self-contained and is
therefore field and/or customer replaceable with minimal effort
using standard tools. In addition, unlike prior art liquid-based
cooling system, the field replaceable packaged refrigeration module
with capillary pumped loop of the invention, in one embodiment,
uses the passive, simple and low energy capillary pumped loop to
perform the majority of the routine cooling, while providing the
added cooling capacity of a liquid-based cooling system in the form
of the intermittently operating field replaceable packaged
refrigeration module. In another embodiment, the field replaceable
packaged refrigeration module is positioned directly over the main
heat source, such as a CPU, while the capillary pumped loop is used
for smaller heat sources or secondary cooling. In addition, unlike
prior art liquid-based cooling systems, the field replaceable
packaged refrigeration module with capillary pumped loop of the
invention is compact and simple in both operation and installation,
with minimal parts to fail or break and minimal added complexity.
Therefore, unlike prior art liquid-based cooling systems, the field
replaceable packaged refrigeration module with capillary pumped
loop of the invention is sturdy and reliable.
[0016] In one embodiment of the invention, a single capillary
pumped loop is coupled to a single field replaceable packaged
refrigeration module as a unit. In other embodiments of the
invention, multiple capillary pumped loops are coupled to, and
serviced by, a single field replaceable packaged refrigeration
module mounted in a central location. In this way, single or
multiple heat sources can be serviced by a single field replaceable
packaged refrigeration module.
[0017] In addition, capillary pumped loop portion of the field
replaceable packaged refrigeration module with capillary pumped
loop of the present invention can be constructed using very small
tubing and evaporator plates and these tubing and evaporator plates
can be used to access electronic devices to be cooled that are in
very constrained spaces.
[0018] In one embodiment of the invention, the capillary pumped
loop portion of the field replaceable packaged refrigeration module
with capillary pumped loop of the present invention is a
"micro-capillary pumped loop" that can be fabricated in the
electronic component to be cooled using existing technology.
[0019] In addition, the field replaceable packaged refrigeration
module portion of the present invention is specifically designed to
be operational in any orientation. Consequently, unlike prior art
liquid-based cooling systems, the field replaceable packaged
refrigeration module portion of the present invention can be
mounted, and operated, at any angle. This makes the field
replaceable packaged refrigeration module with capillary pumped
loop of the present invention particularly well suited for use with
electronic systems.
[0020] As discussed briefly above, and in more detail below, the
field replaceable packaged refrigeration module with capillary
pumped loop of the present invention has the cooling capacity of a
liquid-based cooling system and yet is modular, compact, simple in
design and simple to use, like an air-based cooling system.
Consequently, the field replaceable packaged refrigeration module
with capillary pumped loop of the present invention can readily
meet the cooling needs of the next generation of electronic devices
and systems. As one example, when the field replaceable packaged
refrigeration module with capillary pumped loop of the present
invention is used to cool a microprocessor or CPU, the CPU can
operate at a higher frequency and speed, thereby allowing the
parent electronic system to fully utilize the advances in
microprocessor technology discussed above.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The refrigeration system of the present invention will be
described in the following detailed description, with reference to
the accompanying drawings. In the drawings, the same reference
numbers are used to denote similar components in the various
embodiments.
[0022] FIG. 1 is a functional diagram of a field replaceable
packaged refrigeration module designed according to the principles
of one embodiment of the invention;
[0023] FIG. 2 is a longitudinal cross sectional view of an
exemplary linear compressor that may be used in the field
replaceable packaged refrigeration module depicted in FIG. 1
according to the principles of one embodiment of the invention;
[0024] FIG. 3 is a perspective view of a field replaceable packaged
refrigeration module designed according to the principles of one
embodiment of the invention;
[0025] FIG. 4 is cross sectional view of the field replaceable
packaged refrigeration module of FIG. 3 shown mounted on an
exemplary electrical component according to the principles of one
embodiment of the invention;
[0026] FIG. 5 is a computer-generated representation of one
embodiment of the field replaceable packaged refrigeration module
of FIG. 3 according to the principles of one embodiment of the
invention.
[0027] FIG. 6 is cross sectional view of one embodiment of a field
replaceable packaged refrigeration module with capillary pumped
loop according to the principles of the present invention.
DETAILED DESCRIPTION
[0028] The field replaceable packaged refrigeration module with
capillary pumped loop (600 in FIG. 6) of the present invention has
the advantageous cooling capacity of a prior art liquid-based
cooling system, yet, unlike prior art liquid-based cooling systems,
the field replaceable packaged refrigeration module with capillary
pumped loop of the present invention is suitable for use in
standard electronic component environments.
[0029] In one embodiment of the invention, the addition of the
field replaceable packaged refrigeration module (660 in FIG. 6) to
a capillary pumped loop (690 in FIG. 6) serves to create a system
wherein the capillary pumped loop is used to passively cool the
heat source (62 in FIG. 6) and the field replaceable packaged
refrigeration module is used to lower, or maintain, the base
temperature of the capillary pumped loop. Consequently, the field
replaceable packaged refrigeration module can be operated
intermittently, on an as needed basis, to minimize the power used
by the system and to minimize the wear and tear of the moving
parts. The net result is the ability to manage and remove heat from
the heat source while saving energy since the field replaceable
packaged refrigeration module does not need to operate at all
times. In another embodiment, the field replaceable packaged
refrigeration module is positioned directly over the main heat
source, such as a CPU, while the capillary pumped loop is used for
smaller heat sources or secondary cooling. Consequently, the use of
a capillary pumped loop with the field replaceable packaged
refrigeration module allows for more cooling capability and more
efficient cooling, lowered load on the field replaceable packaged
refrigeration module, and a lower failure rate of the cooling
system and its moving parts.
[0030] The present invention can be utilized in existing electronic
systems and unlike prior art liquid-based cooling systems, the
various parts of the field replaceable packaged refrigeration
module with capillary pumped loop of the invention, including the
very minimal tubing (694 and 696 in FIG. 6), are largely
self-contained in the field replaceable packaged refrigeration
module with capillary pumped loop. Therefore a failure of any of
the tubes would typically not result in the introduction of liquid
into, or onto, the electronic devices and would not cause
catastrophic system failure, as was the risk with prior art
liquid-based cooling systems.
[0031] In one embodiment of the invention, a single capillary
pumped loop is coupled to a single field replaceable packaged
refrigeration module as a unit. In other embodiments of the
invention, multiple capillary pumped loops are coupled to, and
serviced by a single field replaceable packaged refrigeration
module mounted in a central location. In this way, single or
multiple heat sources can be serviced by a single field replaceable
packaged refrigeration module.
[0032] The field replaceable packaged refrigeration module with
capillary pumped loop of the present invention is a modified
liquid-based cooling system and therefore provides the cooling
capacity of a prior art liquid-based cooling systems. However,
unlike prior art liquid-based cooling systems, the field
replaceable packaged refrigeration module with capillary pumped
loop of the invention is modular and self-contained and is
therefore field and/or customer replaceable with minimal effort
using standard tools. In addition, unlike prior art liquid-based
cooling system, the field replaceable packaged refrigeration module
with capillary pumped loop of the invention, in one embodiment,
uses the passive, air cooled, and low energy capillary pumped loop
to perform the majority of the cooling, while providing the added
cooling capacity of a liquid-based cooling system in the form of
the intermittently operating field replaceable packaged
refrigeration module.
[0033] In addition, unlike prior art liquid-based cooling systems,
the field replaceable packaged refrigeration module with capillary
pumped loop of the invention is compact and simple in both
operation and installation, with minimal parts to fail or break and
minimal added complexity. Therefore, unlike prior art liquid-based
cooling systems, the field replaceable packaged refrigeration
module with capillary pumped loop of the invention is sturdy and
reliable.
[0034] In addition, the field replaceable packaged refrigeration
module portion of the present invention is specifically designed to
be operational in any orientation. Consequently, unlike prior art
liquid-based cooling systems, the field replaceable packaged
refrigeration module portion of the present invention can be
mounted, and operated, at any angle. This makes the field
replaceable packaged refrigeration module with capillary pumped
loop of the present invention particularly well suited for use with
electronic systems.
[0035] FIG. 1 is a functional diagram of a field replaceable
packaged refrigeration module 10 designed according to one
embodiment of the invention. Referring to FIG. 1, field replaceable
packaged refrigeration module 10 includes a compressor 12, a
condenser 14, an optional receiver 16, an expansion device 18 and
an evaporator 20, all of which are connected together in
refrigeration loop 22 through which a working fluid, such as water
or ethanol, is circulated.
[0036] As also shown in FIG. 1, compressor 12, condenser 14,
optional receiver 16, expansion device 18 and evaporator 20, in a
refrigeration loop 22 are self-contained in field replaceable
packaged refrigeration module 10, as indicated by dashed line
11.
[0037] In one embodiment of the invention, evaporator 20 is
positioned in thermal contact with a heat source 24, such as an
electronic component, or the base of a capillary pumped loop, as
discussed below, which is to be cooled. In another embodiment of
the invention, evaporator 20 is positioned in thermal contact with
a refrigerant reservoir (693 in FIG. 6) of a capillary pumped loop
(690 in FIG. 6).
[0038] As is well understood by those of ordinary skill in the art,
compressor 12 compresses the refrigerant (not shown) into a
high-pressure, high temperature liquid that is then conveyed to
condenser 14. At condenser 14, the refrigerant is allowed to cool
before being conveyed to receiver 16. From receiver 16, the
refrigerant passes through expansion device 18, which may be, for
example, a capillary tube, and into evaporator 20. The liquid
refrigerant evaporates in evaporator 20 and in the process absorbs
heat from heat source 24 to produce the desired cooling effect.
From evaporator 20 the refrigerant is drawn back into compressor 12
to begin another cycle through refrigeration loop 22.
[0039] In accordance with the present invention, compressor 12 is
one of several new generation compressors that are relatively
small, on the order of 2.0 inches in diameter and 3 to 4 inches
long. In one embodiment of the invention, compressor 12 is less
than 1.7 inches in diameter and less than 4 inches long. One
example of this new generation of compressors is the relatively new
linear compressor now being used in the more standard
refrigeration, i.e., non-electronics, industry. In one embodiment
of the invention, compressor 12 is a linear compressor whose
operation is controlled by drive circuit 26.
[0040] As discussed in more detail with respect to FIG. 2, a linear
compressor is a positive displacement compressor having one or more
free floating pistons that are driven directly by a linear motor.
Thus, a linear compressor differs from a conventional reciprocating
and rotary compressor where the pistons are driven through a
crankshaft linkage, or by a rotary motor through a mechanical
linkage, respectively. Since the capacity of any compressor is
directly related to the size and displacement of the pistons, a
linear compressor can typically be made smaller than a crankshaft
reciprocating or rotary compressor but can maintain the same
capacity since the displacement of the pistons is not dependent on
the size of a mechanical linkage. In addition, since a linear
compressor usually comprises fewer moving parts than a crankshaft
reciprocating or rotary compressor, the linear compressor is
typically quieter than a crankshaft reciprocating or rotary
compressor. Furthermore, since the pistons of a double-piston
linear compressor move in opposition to one another, the reaction
forces of the pistons will cancel each other out and the vibrations
that are commonly experienced with crankshaft reciprocating or
rotary compressors will consequently be suppressed. Consequently,
linear compressors offer many advantages over a crankshaft
reciprocating compressor or a rotary compressor for application as
compressor 12 in field replaceable packaged refrigeration module
10.
[0041] The linear compressors suitable for use as compressor 12 in
field replaceable packaged refrigeration module 10 can be any of a
variety of single, double or multiple-piston linear compressors
that are known in the art. For example, in one embodiment of the
invention, linear compressor 12 is a single-piston linear
compressor of the type disclosed in U.S. Pat. No. 5,993,178, which
is hereby incorporated herein by reference, or a double-piston
linear compressor of the type disclosed in U.S. Pat. No. 6,089,836
or U.S. Pat. No. 6,398,523, all of which are hereby incorporated
herein by reference.
[0042] Referring to FIG. 2, an exemplary linear compressor 120,
suitable for use as compressor 12 in FIG. 1, comprises a housing
28, first and second cylinders 30, 32 which are connected to, or
formed integrally with, housing 28, and first and second pistons
34, 36 which are slidably received within first and second
cylinders 30, 32, respectively. The ends of housing 28 are, in one
embodiment, hermetically sealed, such as by end plates 38. In
addition, each cylinder 30, 32 has an axial centerline CL that is,
in one embodiment, coaxial with that of the other cylinder.
Furthermore, housing 28 is, in one embodiment, constructed of a
magnetically permeable material, such as stainless steel, and
pistons 34, 36 are optimally constructed of a magnetically
indifferent material, such as plastic or ceramic.
[0043] In the embodiment of exemplary linear compressor 120 shown
in FIG. 2, each piston 34, 36 is driven within its respective
cylinder 30, 32 by linear motor 40. Each motor 40 includes a
ring-shaped permanent magnet 42 and an associated electrical coil
44. In the embodiment of an exemplary linear compressor 120 shown
in FIG. 2, magnet 42 is mounted within housing 28 and coil 44 is
wound upon a portion of piston 34, 36. In one embodiment, magnet 42
is radially charged, and each motor 40 includes a cylindrical core
46 mounted within housing 28 adjacent magnet 42 to direct the flux
lines (not shown) from magnet 42 across coil 44. In one embodiment,
coil 44 is energized by an AC current, from drive circuit 26 (FIG.
1), over a corresponding lead wire (not shown). In one embodiment
of the invention, drive circuit 26 is programmed such that, when
the AC current is applied to coils 44 (FIG. 2), pistons 34, 36 will
reciprocate toward and away from each other along the axial
centerline CL of cylinders 30, 32. In another embodiment, DC
current is applied. In one embodiment, spring 48, or similar means,
may be connected between each piston 34, 36 and adjacent end plate
38 to aid in matching the natural frequency of piston 34, 36 to the
frequency of the current from drive circuit 26 (FIG. 1).
[0044] The embodiment of an exemplary linear compressor 120 shown
in FIG. 2 also includes a compression chamber 50 located within
cylinders 30, 32, between pistons 34, 36. During the expansion
portion of each operating cycle of linear compressor 120, motors 40
will move pistons 34, 36 away from each other. This will cause the
then gaseous refrigerant within evaporator 20 (FIG. 1) to be drawn
into compression chamber 50 (FIG. 2), through an inlet port 52 in
housing 28. During the successive compression portion of the
operating cycle of exemplary linear compressor 120, motors 40 will
move pistons 34, 36 toward each other. Pistons 34, 36 will
consequently compress the then gaseous refrigerant within
compression chamber 50 into a liquid and eject it into condenser 14
(FIG. 1), through an outlet port 54 (FIG. 2) in housing 28. In one
embodiment, suitable check valves 56, 58 are provided in inlet and
outlet ports 52, 54, respectively, to control the flow of
refrigerant through inlet and outlet ports 52, 54 during the
expansion and compression portions of each operating cycle.
[0045] While a specific embodiment of a field replaceable packaged
refrigeration module 10 is discussed above that includes exemplary
linear compressor 120, those of skill in the art will recognize
that the choice of a linear compressor, or any particular
compressor, for use as compressor 12 in the discussion above was
made for illustration simplicity and to avoid detracting from the
invention by describing multiple specific embodiments at one time.
In other embodiments of the invention appropriately sized rotary
compressor, or other type of compressor, can be used as compressor
12. For instance, in various embodiments of the invention,
compressor 12 can be: a reciprocating compressor; a Swash-plate
compressor; a rolling piston compressor; a scroll compressor; a
rotary vane compressor; a screw compressor; an aerodynamic-turbo
compressor; an aerodynamic-axial compressor; or any other
reciprocating, volumetric or aerodynamic compressor known in the
art, or developed after this application is filed. Consequently,
the present invention should not be read as being limited the
particular embodiments discussed above using linear, or any
specific, compressor types.
[0046] Consequently, the present invention should not be read as
being limited the particular embodiments discussed above using
linear, or any specific, compressor types.
[0047] In one embodiment of the invention, a single capillary
pumped loop (690 in FIG. 6) is coupled to a single field
replaceable packaged refrigeration module 10 as a unit. In other
embodiments of the invention, multiple capillary pumped loops (690
in FIG. 6) are coupled to, and serviced by a single field
replaceable packaged refrigeration module 10 mounted in a central
location. In this way, single or multiple heat sources can be
serviced by a single field replaceable packaged refrigeration
module. In addition, according to the principles of the invention,
field replaceable packaged refrigeration module 10 can be readily
adapted for use in cooling one or more integrated circuits that are
mounted on a single circuit board and are part of a larger
electronic system. For example, in many computer servers a number
of integrated circuits are mounted on a single circuit board that,
in turn, is housed within an enclosure/cabinet or "rack unit", and
a number of such rack units are, in turn, mounted in corresponding
racks that are supported in the housing of the server.
[0048] In accordance with one industry standard, each rack unit has
a height of only 1.75 inches. This fact makes use of prior art
liquid-based cooling systems extremely difficult, if not
impossible, and makes the extensive, and potentially disastrous,
plumbing, discussed above, a system requirement. In contrast, a
single, or even multiple, field replaceable packaged refrigeration
modules 10, designed according to the principles of the invention,
can be positioned within the housing of the server, and/or on the
rack units, to directly cool the integrated circuits that are
located within or on the rack units or to provide additional
cooling for capillary pumped loops (690 in FIG. 6) cooling the
integrated circuits that are located within or on the rack units.
Consequently, in one embodiment of the invention, field replaceable
packaged refrigeration modules 10, designed according to the
invention, are housed within a small scale-cooling unit that can be
located within each rack unit and connected directly to cool each
integrated circuit or capillary pumped loop as needed.
[0049] One example of a physical implementation of the functional
diagram of a field replaceable packaged refrigeration module 10 of
FIG. 1 is shown as field replaceable packaged refrigeration module
60 of FIG. 3, FIG. 4 and FIG. 5. As shown in FIGS. 3 and 4,
according to one embodiment of the invention, field replaceable
packaged refrigeration module 60 is positioned adjacent an
integrated circuit 62 that is mounted on a circuit board 64 or a
capillary pumped loop (690 in FIG. 6) mounted on integrated circuit
62 on a circuit board 64. As discussed above, in accordance with
one embodiment of the invention, field replaceable packaged
refrigeration module 60 is sized such that, when positioned as
shown in FIG. 4, field replaceable packaged refrigeration module 60
will fit within a rack unit of a conventional computer server or a
telecommunications rack. In one embodiment of the invention, field
replaceable packaged refrigeration module 60 has a length 301 (FIG.
3) of approximately 6 inches, a width 303 of approximately 4
inches, and a height 305 of approximately 1.75 inches. In another
embodiment of the invention, field replaceable packaged
refrigeration module 60 has a length 301 of approximately 5 inches,
a width 303 of approximately 4 inches, and a height 305 of
approximately 1.75 inches. Of course, those of skill in the art
will recognize that length 301, width 303 and height 305 of field
replaceable packaged refrigeration module 60 can be varied to meet
the needs of specific applications.
[0050] As shown in FIG. 3, in one embodiment of the invention,
field replaceable packaged refrigeration module 60 includes a
housing 66 which has generally open front and back sides 68, 70, a
conventional air-cooled condenser 14, which is mounted within
housing 66 between open front and back sides 68, 70, a compressor
12 which is connected to housing 66 by a suitable bracket 72, and
an evaporator 20 which is connected to housing 66, below condenser
14. As discussed above, in one embodiment of the invention,
compressor 12 is a linear compressor driven by a drive circuit (not
shown) in a manner similar to that discussed above. In one
embodiment of the invention, evaporator 20 is a conventional cold
plate-type evaporator that is thermally coupled to the top of
integrated circuit 62 (FIG. 4) by either custom or conventional
means. As discussed in more detail below, in another embodiment of
the invention, field replaceable packaged refrigeration module 60
is coupled to the evaporator (620 in FIG. 6) of a capillary pumped
loop (690 in FIG. 6) by either custom or conventional means. In
another embodiment of the invention, field replaceable packaged
refrigeration module 60 is coupled to a refrigerant reservoir (693
in FIG. 6) of a capillary pumped loop (690 in FIG. 6).
[0051] In one embodiment of the invention, condenser 14 is cooled
by a flow of air from a system fan (not shown) that is mounted in
the housing (not shown) of the server (not shown). In addition, in
one embodiment of the invention, field replaceable packaged
refrigeration module 60 is connected to circuit board 64 with a
number of standoffs 74 and screws 76.
[0052] During the normal operation of field replaceable packaged
refrigeration module 60, relatively high-pressure liquid
refrigerant from compressor 12 is conveyed through a conduit 76 to
condenser 14. In one embodiment of the invention, the high-pressure
liquid refrigerant is cooled in condenser 14 by the flow of air
from a system fan (not shown). The refrigerant is then conveyed
through a capillary tube 78 to evaporator 20. The refrigerant
evaporates in evaporator 20 and in the process absorbs heat from
integrated circuit 62 to thereby cool integrated circuit 62 (FIG.
4). The now gaseous refrigerant is then drawn back into compressor
12 through conduit 80. This cycle is then repeated as required to
produce a desired cooling effect for integrated circuit 62.
[0053] FIG. 5 is a computer-generated representation of one
embodiment of field replaceable packaged refrigeration module 60 of
FIG. 3 and FIG. 4 and therefore represents a computer-generated
representation of a physical implementation of the functional
diagram of field replaceable packaged refrigeration module 10 of
FIG. 1. Shown in FIG. 5 are: condenser 14; compressor 12;
evaporator 20; and tubing 501. It is worth noting that tubing 501
is relatively minimal and, is therefore, a substantial improvement
over the extensive "plumbing" associated with prior art
liquid-based cooling systems. Indeed, unlike prior art liquid-based
cooling systems, the various parts of field replaceable packaged
refrigeration module 60 of the invention, including the very
minimal tubing 501, are self-contained in field replaceable
packaged refrigeration module 60 and therefore a failure of any of
the tubes 501 would typically not result in the introduction of
liquid into or onto the electronic devices (62 in FIG. 4) and would
not cause the catastrophic system failure that was the risk
associated with prior art liquid-based cooling systems.
[0054] As noted above, it is highly desirable to provide a cooling
system that uses minimal power and has a large thermal inertia. In
these applications, a passive refrigeration sub-system is coupled
with the field replaceable packaged refrigeration module discussed
above to yield a hybrid system that is more power efficient than
the field replaceable packaged refrigeration module used alone.
[0055] FIG. 6 is cross sectional view of one embodiment of a field
replaceable packaged refrigeration module with capillary pumped
loop 600 according to the principles of the present invention. As
shown in FIG. 6, according to one embodiment of the invention,
field replaceable packaged refrigeration module 660 is thermally
coupled by capillary tubing 694 and a cold plate evaporator 620 to
adjacent a heat source 62, such an integrated circuit or CPU. As
discussed above, in accordance with one embodiment of the
invention, field replaceable packaged refrigeration module 660, and
field replaceable packaged refrigeration module with capillary
pumped loop 600, is sized such that, when positioned as shown in
FIG. 6, field replaceable packaged refrigeration module 660 will
fit within a rack unit of a conventional computer server or a
telecommunications rack.
[0056] As shown in FIG. 6, in one embodiment of the invention,
field replaceable packaged refrigeration module 660 includes a
conventional air-cooled condenser 614 coupled to a compressor 612
by tubing 696. As discussed above, in one embodiment of the
invention, compressor 612 is a linear compressor driven by a drive
circuit (not shown) in a manner similar to that discussed above. In
one embodiment of the invention, condenser 614 is cooled by a flow
of air from a system fan (not shown) that is mounted in the housing
(not shown) of the server (not shown).
[0057] As also shown in FIG. 6, field replaceable packaged
refrigeration module 660 includes a cold-plate evaporator 620. In
one embodiment of the invention, cold-plate evaporator 620 is a
conventional cold plate-type evaporator that is thermally coupled
to the top of heat source 62 by conventional means. In one
embodiment of the invention, cold plate evaporator 620 of field
replaceable packaged refrigeration module 660 is coupled to field
replaceable packaged refrigeration module 660 by capillary tubes
694.
[0058] As shown in FIG. 6, in one embodiment of the invention,
capillary pumped loop 690 also includes: an evaporator 691; a
refrigerant reservoir 693, holding a refrigerant or working fluid
such as water, ethanol or a dielectric coolant; capillary pumped
loop condenser 695 coupled to evaporator 691 by tubing 699.
[0059] Capillary pumped loops, such as capillary pumped loop 690,
and their operation is well known in the art. Therefore, a detailed
description of capillary pumped loop 690 is omitted here to avoid
detracting from the invention.
[0060] The addition of the field replaceable packaged refrigeration
module 660 to capillary pumped loop 690 serves to create a system
600 wherein capillary pumped loop 690 is used to passively cool
heat source 62 and field replaceable packaged refrigeration module
660 is used to lower, or maintain, the base temperature of
capillary pumped loop 690. Consequently, field replaceable packaged
refrigeration module 660 can be operated intermittently, on an as
needed basis, to minimize the power used by field replaceable
packaged refrigeration module with capillary pumped loop 600 and to
minimize the wear and tear of the moving parts. The net result is
the ability to manage and remove heat from heat source 62 while
saving energy since field replaceable packaged refrigeration module
660 does not need to operate at all times.
[0061] In addition, the addition of the field replaceable packaged
refrigeration module 660 to a capillary pumped loop 690 serves to
create a system 600 wherein vibration transferred from field
replaceable packaged refrigeration module 660 to the often delicate
heat source 62 to be cooled is significantly reduced because, as
discussed above, according to the invention, the field replaceable
packaged refrigeration module 660 can be operated intermittently,
on an as needed basis.
[0062] In one embodiment of the invention, a temperature sensor
(not shown) is used to monitor the temperature of a component, such
as cold plate evaporator 620 of field replaceable packaged
refrigeration module 660 or a surface of heat source 62. In one
embodiment of the invention, when a predetermined "maximum" base
temperature is exceeded, compressor 612 of field replaceable
packaged refrigeration module 660 is started, typically via a
switch (not shown), and field replaceable packaged refrigeration
module 660 operates until the base temperature of capillary pumped
loop 690 is lowered to a predetermined level. Consequently, the use
of capillary pumped loop 690 with field replaceable packaged
refrigeration module 660 allows for more cooling capability and
more efficient cooling, lowered load on field replaceable packaged
refrigeration module 660, and a lower failure rate of field
replaceable packaged refrigeration module with capillary pumped
loop 600 and its moving parts.
[0063] In another embodiment of the invention, heat source 62 is a
microprocessor whose activity is monitored by a monitoring device
implemented in hardware or software (not shown). In this embodiment
of the invention, when a predetermined activity level for the
processor is reached, compressor 612 of field replaceable packaged
refrigeration module 660 is started, typically via a switch (not
shown), and field replaceable packaged refrigeration module 660
operates until the activity level of the processor drops below a
predetermined level. Consequently, in this embodiment of the
invention, field replaceable packaged refrigeration module with
capillary pumped loop 600 tries to anticipate cooling needs and
operates to provide the thermal reservoir to handle increases in
activity before the heat is produced. Therefore, thermal spikes,
and potential thermal damage to the processor and its performance
are avoided.
[0064] In one embodiment of the invention, a single capillary
pumped loop 690 is coupled to a single field replaceable packaged
refrigeration module 660 as a unit 600. In other embodiments of the
invention, multiple capillary pumped loops 690 are coupled to, and
serviced by, a single field replaceable packaged refrigeration
module 660 mounted in a central location. In this way, single or
multiple heat sources 62 can be serviced by a single field
replaceable packaged refrigeration module.
[0065] As discussed above, the present invention is directed to a
field and/or customer replaceable packaged refrigeration module
with capillary pumped loop that is suitable for use in standard
electronic component environments. According to the present
invention, advances in compressor technology are incorporated in a
field replaceable packaged refrigeration module that is coupled to
a capillary pumped loop cold plate evaporator to be used for
cooling electronic components. According to the invention, the
field replaceable packaged refrigeration module is self-contained
and is specifically designed to have physical dimensions similar to
those of a standard air-based cooling system, such as a fined heat
sink or heat pipe.
[0066] As discussed above, in one embodiment of the invention, the
addition of the field replaceable packaged refrigeration module to
a capillary pumped loop serves to create a system wherein the
capillary pumped loop is used to passively cool the heat source and
the field replaceable packaged refrigeration module is used to
lower, or maintain, the base temperature of the capillary pumped
loop and/or the associated capillary pumped loop working fluid
reservoir. Consequently, the field replaceable packaged
refrigeration module can be operated intermittently, on an as
needed basis, to minimize the power used by the system and to
minimize the wear and tear of the moving parts. The net result is
the ability to manage and remove heat from the heat source while
saving energy since the field replaceable packaged refrigeration
module does not need to operate at all times. Consequently, the use
of a capillary pumped loop with the field replaceable packaged
refrigeration module allows for more cooling capability and more
efficient cooling, lowered load on the field replaceable packaged
refrigeration module, and a lower failure rate of the cooling
system and its moving parts.
[0067] In addition, the addition of the field replaceable packaged
refrigeration module to a capillary pumped loop serves to create a
system wherein vibration transferred from the field replaceable
packaged refrigeration module to the often delicate electronic
component to be cooled is significantly reduced because, as
discussed above, the field replaceable packaged refrigeration
module can be operated intermittently, on an as needed basis.
[0068] As discussed above, the present invention can be utilized in
existing electronic systems and unlike prior art liquid-based
cooling systems, the various parts of the field replaceable
packaged refrigeration module with capillary pumped loop of the
invention, including the very minimal tubing, are largely
self-contained in the field replaceable packaged refrigeration
module with capillary pumped loop. Therefore a failure of any of
the tubes would typically not result in the introduction of liquid
into, or onto, the electronic devices and would not cause
catastrophic system failure, as was the risk with prior art
liquid-based cooling systems.
[0069] As discussed above, the field replaceable packaged
refrigeration module with capillary pumped loop of the present
invention is a modified liquid-based cooling system and therefore
provides the cooling capacity of a prior art liquid-based cooling
systems. However, unlike prior art liquid-based cooling systems,
the field replaceable packaged refrigeration module with capillary
pumped loop of the invention is modular and largely self-contained
and is therefore field and/or customer replaceable with minimal
effort using standard tools. In addition, unlike prior art
liquid-based cooling system, the field replaceable packaged
refrigeration module with capillary pumped loop of the invention,
in one embodiment, uses the passive, simple and low energy
capillary pumped loop to perform the majority of the routine
cooling, while providing the added cooling capacity of a
liquid-based cooling system in the form of the intermittently
operating field replaceable packaged refrigeration module. In
another embodiment, the field replaceable packaged refrigeration
module is positioned directly over the main heat source, such as a
CPU, while the capillary pumped loop is used for smaller heat
sources or secondary cooling. In addition, unlike prior art
liquid-based cooling systems, the field replaceable packaged
refrigeration module with capillary pumped loop of the invention is
compact and simple in both operation and installation, with minimal
parts to fail or break and minimal added complexity. Therefore,
unlike prior art liquid-based cooling systems, the field
replaceable packaged refrigeration module with capillary pumped
loop of the invention is sturdy and reliable.
[0070] As discussed above, in one embodiment of the invention, a
single capillary pumped loop is coupled to a single field
replaceable packaged refrigeration module as a unit. In other
embodiments of the invention, multiple capillary pumped loops are
coupled to, and serviced by, a single field replaceable packaged
refrigeration module mounted in a central location. In this way,
single or multiple heat sources can be serviced by a single field
replaceable packaged refrigeration module.
[0071] In addition, capillary pumped loop portion of the field
replaceable packaged refrigeration module with capillary pumped
loop of the present invention can be constructed using very small
tubing and evaporator plates and these tubing and evaporator plates
can be used to access electronic devices to be cooled that are in
very constrained spaces.
[0072] As discussed above, in one embodiment of the invention, the
capillary pumped loop portion of the field replaceable packaged
refrigeration module with capillary pumped loop of the present
invention is a "micro-capillary pumped loop" that can be fabricated
in the electronic component to be cooled using existing
technology.
[0073] In addition, the field replaceable packaged refrigeration
module portion of the present invention is specifically designed to
be operational in any orientation. Consequently, unlike prior art
liquid-based cooling systems, the field replaceable packaged
refrigeration module portion of the present invention can be
mounted, and operated, at any angle. This makes the field
replaceable packaged refrigeration module with capillary pumped
loop of the present invention particularly well suited for use with
electronic systems. It should be recognized that, while the present
invention has been described in relation to the specific
embodiments thereof discussed above, those skilled in the art might
develop a wide variation of structural and operational details
without departing from the principles of the invention.
[0074] As one example, the choice of a linear compressor, or any
particular linear compressor, for use as compressor 612 in the
discussion above was made for illustration simplicity and to avoid
detracting from the invention by describing multiple specific
embodiments at one time. In other embodiments of the invention,
appropriately sized rotary compressors, or other compressors, can
be used as compressor 612. For instance, in various embodiments of
the invention, compressor 612 can be: a reciprocating compressor; a
swash-plate compressor; a rolling piston compressor; a scroll
compressor; a rotary vane compressor; a screw compressor; an
aerodynamic-turbo compressor; an aerodynamic-axial compressor; or
any other reciprocating, volumetric or aerodynamic compressor known
in the art, or developed after this application is filed.
Consequently, the present invention should not be read as being
limited the particular embodiments discussed above using linear, or
any specific, compressor types.
[0075] As another example, specific dimensions were discussed above
as examples of possible values for length 301, width 303 and height
305 of field replaceable packaged refrigeration module 60 or 660.
Those of skill in the art will recognize that length 301, width 303
and height 305 of field replaceable packaged refrigeration module
60 or 660 can be varied for specific applications and that the
present invention should not be read as being limited the
particular embodiments discussed above with the particular
dimensions discussed by way of illustration.
* * * * *