U.S. patent application number 12/939552 was filed with the patent office on 2012-05-10 for vapor-compression refrigeration apparatus with refrgierant bypass and controlled heat load.
This patent application is currently assigned to INTERNATIONAL BUSINESS MACHINES CORPORATION. Invention is credited to Levi A. CAMPBELL, Richard C. CHU, Michael J. ELLSWORTH, JR., Madhusudan K. IYENGAR, Robert E. SIMONS.
Application Number | 20120111037 12/939552 |
Document ID | / |
Family ID | 46018350 |
Filed Date | 2012-05-10 |
United States Patent
Application |
20120111037 |
Kind Code |
A1 |
CAMPBELL; Levi A. ; et
al. |
May 10, 2012 |
VAPOR-COMPRESSION REFRIGERATION APPARATUS WITH REFRGIERANT BYPASS
AND CONTROLLED HEAT LOAD
Abstract
Apparatus and method are provided for cooling an electronic
component. The apparatus includes a refrigerant evaporator in
thermal communication with the component(s) to be cooled, and a
refrigerant loop coupled in fluid communication with the evaporator
for facilitating flow of refrigerant through the evaporator. The
apparatus further includes a compressor in fluid communication with
the refrigerant loop, a refrigerant bypass pipe coupled to the
refrigerant loop in parallel fluid communication with the
evaporator, and a control valve for controlling refrigerant flow
through the evaporator. The control valve is controlled to maintain
temperature of the component(s) within a specified temperature
range. The apparatus further includes a controllable refrigerant
heater associated with the refrigerant bypass pipe for providing an
adjustable heat load on refrigerant in the bypass pipe to ensure
that refrigerant entering the compressor is in a superheated
thermodynamic state.
Inventors: |
CAMPBELL; Levi A.;
(Poughkeepsie, NY) ; CHU; Richard C.; (Hopewell
Junction, NY) ; ELLSWORTH, JR.; Michael J.;
(Lagrangeville, NY) ; IYENGAR; Madhusudan K.;
(Woodstock, NY) ; SIMONS; Robert E.;
(Poughkeepsie, NY) |
Assignee: |
INTERNATIONAL BUSINESS MACHINES
CORPORATION
Armonk
NY
|
Family ID: |
46018350 |
Appl. No.: |
12/939552 |
Filed: |
November 4, 2010 |
Current U.S.
Class: |
62/115 ; 62/159;
62/259.2; 62/474 |
Current CPC
Class: |
F25B 49/02 20130101;
H05K 7/20809 20130101; F25B 2400/01 20130101; F25B 2500/28
20130101; H05K 7/20836 20130101 |
Class at
Publication: |
62/115 ; 62/474;
62/159; 62/259.2 |
International
Class: |
F25B 1/00 20060101
F25B001/00; F25B 29/00 20060101 F25B029/00; F25D 31/00 20060101
F25D031/00; F25D 15/00 20060101 F25D015/00 |
Claims
1. An apparatus for facilitating cooling of an electronic
component, the apparatus comprising: a refrigerant evaporator in
thermal communication with the electronic component, the
refrigerant evaporator comprising at least one channel therein for
accommodating flow of refrigerant therethrough; a refrigerant loop
coupled in fluid communication with the at least one channel of the
refrigerant evaporator for facilitating flow of refrigerant
therethrough; a compressor coupled in fluid communication with the
refrigerant loop; a refrigerant bypass pipe coupled to the
refrigerant loop in parallel fluid communication with the
refrigerant evaporator; a control valve for controlling refrigerant
flow through the at least one channel of the refrigerant
evaporator, the control valve being controlled to maintain
temperature of the electronic component within a specified
temperature range; and a controllable refrigerant heater to heat
refrigerant in the refrigerant loop, the controllable refrigerant
heater being controlled to selectively heat refrigerant in the
refrigerant loop to ensure that refrigerant in the refrigerant loop
entering the compressor is in a superheated thermodynamic
state.
2. The apparatus of claim 1, wherein the controllable refrigerant
heater is coupled to the refrigerant bypass pipe to controllably
heat refrigerant passing through the refrigerant bypass pipe to
ensure that refrigerant in the refrigerant loop entering the
compressor is in a superheated thermodynamic state.
3. The apparatus of claim 1, wherein the control valve is
controlled to maintain temperature of the electronic component
within the specified temperature range responsive to a changing
electronic component heat load.
4. The apparatus of claim 1, further comprising a temperature
sensor for monitoring a temperature associated with the electronic
component, and a controller coupled to the temperature sensor and
the control valve, the controller automatically, incrementally
opening the control valve further responsive to the monitored
temperature of the electronic component being below to a first
specified temperature, and automatically, incrementally closing the
control valve further responsive to the monitored temperature of
the electronic component being above a second specified
temperature, wherein the first specified temperature is higher than
the second specified temperature.
5. The apparatus of claim 1, wherein the control valve comprises an
electronically-controlled, three-way valve, and wherein the
refrigerant bypass pipe couples at one end in fluid communication
with the refrigerant loop through the electronically-controlled,
three-way valve, wherein variation in refrigerant flow through the
at least one channel of the refrigerant evaporator results in
variation of refrigerant flow through the refrigerant bypass pipe,
and wherein the controllable refrigerant heater is coupled to the
refrigerant bypass pipe.
6. The apparatus of claim 1, further comprising a fixed expansion
orifice in fluid communication with the refrigerant loop for
expanding refrigerant passing therethrough, the fixed expansion
orifice being disposed at a refrigerant inlet to the refrigerant
evaporator.
7. The apparatus of claim 1, further comprising a controller
coupled to the controllable refrigerant heater for automatically
controlling a heat load applied by the controllable refrigerant
heater to refrigerant in the refrigerant loop.
8. The apparatus of claim 7, wherein the controllable refrigerant
heater is coupled to the refrigerant bypass pipe, and the
controller automatically adjusts heat load applied by the
controllable refrigerant heater to refrigerant passing through the
refrigerant bypass pipe responsive to a change in heat load of the
electronic component.
9. The apparatus of claim 8, wherein the controller periodically
monitors a current heat load of the electronic component and,
responsive thereto, automatically determines whether the current
heat load of the electronic component is above a specified heat
load, and responsive to the current heat load of the electronic
component being above the specified heat load, automatically sets
the heat load applied by the controllable refrigerant heater to
refrigerant passing through the refrigerant bypass pipe to zero,
and responsive to the current heat load of the electronic component
being below the specified heat load, automatically sets the heat
load applied by the controllable refrigerant heater to refrigerant
passing through the refrigerant bypass pipe to the specified heat
load less the current heat load of the electronic component.
10. The apparatus of claim 7, further comprising a refrigerant
temperature sensor and a refrigerant pressure sensor for monitoring
a temperature and a pressure of refrigerant, respectively, within
the refrigerant loop, and wherein the controller automatically
adjusts heat load applied by the controllable refrigerant heater
with reference to the monitored temperature of refrigerant and
pressure of refrigerant within the refrigerant loop, wherein heat
load applied by the controllable refrigerant heater is
automatically increased responsive to refrigerant entering the
compressor being superheated by less than a specified delta
temperature threshold, and is automatically decreased responsive to
refrigerant entering the compressor being superheated by greater
than the specified delta temperature threshold.
11. A cooled electronic system comprising: an electronic component;
and an apparatus for facilitating cooling of the electronic
component, the apparatus comprising: a refrigerant evaporator in
thermal communication with the electronic component, the
refrigerant evaporator comprising at least one channel therein for
accommodating flow of refrigerant therethrough; a refrigerant loop
coupled in fluid communication with the at least one channel of the
refrigerant evaporator for facilitating flow of refrigerant
therethrough; a compressor coupled in fluid communication with the
refrigerant loop; a refrigerant bypass pipe coupled to the
refrigerant loop in parallel fluid communication with the
refrigerant evaporator; a control valve for controlling refrigerant
flow through the at least one channel of the cold plate, the
control valve being controlled to maintain temperature of the
electronic component within a specified temperature range; and a
controllable refrigerant heater to heat refrigerant in the
refrigerant loop, the controllable refrigerant heater being
controlled to selectively heat refrigerant in the refrigerant loop
to ensure that refrigerant in the refrigerant loop entering the
compressor is in a superheated thermodynamic state.
12. The cooled electronic system of claim 11, wherein the
controllable refrigerant heater is coupled to the refrigerant
bypass pipe to controllably heat refrigerant passing through the
refrigerant bypass pipe to ensure that refrigerant in the
refrigerant loop entering the compressor is in a superheated
thermodynamic state.
13. The cooled electronic system of claim 11, further comprising a
temperature sensor for monitoring a temperature associated with the
electronic component, and a controller coupled to the temperature
sensor and the control valve, the controller automatically,
incrementally opening the control valve further responsive to the
monitored temperature of the electronic component being below to a
first specified temperature, and automatically, incrementally
closing the control valve further responsive to the monitored
temperature of the electronic component being above a second
specified temperature, wherein the first specified temperature is
higher than the second specified temperature.
14. The cooled electronic system claim 11, wherein the control
valve comprises an electronically-controlled, three-way valve, and
wherein the refrigerant bypass pipe couples at one end in fluid
communication with the refrigerant loop through the
electronically-controlled, three-way valve, wherein variation in
refrigerant flow through the at least one channel of the
refrigerant evaporator results in variation of refrigerant flow
through the refrigerant bypass pipe, and wherein the controllable
refrigerant heater is coupled to the refrigerant bypass pipe.
15. The cooled electronic system of claim 11, further comprising a
fixed expansion orifice in fluid communication with the refrigerant
loop for expanding refrigerant passing therethrough, the fixed
expansion orifice being disposed at a refrigerant inlet to the
refrigerant evaporator.
16. The cooled electronic system of claim 11, further comprising a
controller coupled to the controllable refrigerant heater for
automatically controlling a heat load applied by the controllable
refrigerant heater to refrigerant in the refrigerant loop.
17. The cooled electronic system of claim 16, wherein the
controllable refrigerant heater is coupled to the refrigerant
bypass pipe, and the controller automatically adjusts heat load
applied by the controllable refrigerant heater to refrigerant
passing through the refrigerant bypass pipe responsive to a change
in heat load of the electronic component.
18. The cooled electronic system of claim 17, wherein the
controller periodically monitors a current heat load of the
electronic component and, responsive thereto, automatically
determines whether the current heat load of the electronic
component is above a specified heat load, and responsive to the
current heat load of the electronic component being above the
specified heat load, automatically sets the heat load applied by
the controllable refrigerant heater to refrigerant passing through
the refrigerant bypass pipe to zero, and responsive to the current
heat load of the electronic component being below the specified
heat load, automatically sets the heat load applied by the
controllable refrigerant heater to refrigerant passing through the
refrigerant bypass pipe to the specified heat load less the current
heat load of the electronic component.
19. The cooled electronic system of claim 16, further comprising a
refrigerant temperature sensor and a refrigerant pressure sensor
for monitoring a temperature and a pressure of refrigerant,
respectively, within the refrigerant loop, and wherein the
controller automatically adjusts heat load applied by the
controllable refrigerant heater with reference to the monitored
temperature of refrigerant and pressure of refrigerant within the
refrigerant loop, wherein heat load applied by the controllable
refrigerant heater is automatically increased responsive to
refrigerant entering the compressor being superheated by less than
a specified delta temperature threshold, and is automatically
decreased responsive to refrigerant entering the compressor being
superheated by greater than the specified delta temperature
threshold.
20. A method of facilitating cooling of an electronic component,
the method comprising: coupling in thermal communication a
refrigerant evaporator to the electronic component, the refrigerant
evaporator comprising at least one channel therein for
accommodating flow of refrigerant therethrough; providing a
refrigerant loop in fluid communication with the at least one
channel of the refrigerant evaporator for facilitating flow of
refrigerant therethrough; coupling a compressor in fluid
communication with the refrigerant loop; providing a refrigerant
bypass pipe coupled to the refrigerant loop in parallel fluid
communication with the refrigerant evaporator; providing a control
valve for controlling refrigerant flow through the at least one
channel of the refrigerant evaporator, the control valve being
controlled to maintain temperature of the electronic component
within a specified temperature range; and associating a
controllable refrigerant heater in thermal communication with
refrigerant in the refrigerant loop, the controllable refrigerant
heater being controlled to selectively heat refrigerant in the
refrigerant loop to ensure that refrigerant entering the compressor
is in a superheated thermodynamic state.
Description
BACKGROUND
[0001] The present invention relates to heat transfer mechanisms,
and more particularly, to cooling apparatuses, liquid-cooled
electronics racks and methods of fabrication thereof for removing
heat generated by one or more electronic components of the
electronics rack.
[0002] The power dissipation of integrated circuit chips, and the
modules containing the chips, continues to increase in order to
achieve increases in processor performance. This trend poses a
cooling challenge at both the module and system levels. Increased
airflow rates are needed to effectively cool higher power modules
and to limit the temperature of the air that is exhausted into the
computer center.
[0003] In many large server applications, processors along with
their associated electronics (e.g., memory, disk drives, power
supplies, etc.) are packaged in removable drawer configurations
stacked within a rack or frame. In other cases, the electronics may
be in fixed locations within the rack or frame. Typically, the
components are cooled by air moving in parallel airflow paths,
usually front-to-back, impelled by one or more air moving devices
(e.g., fans or blowers). In some cases it may be possible to handle
increased power dissipation within a single drawer by providing
greater airflow, through the use of a more powerful air moving
device(s) or by increasing the rotational speed (i.e., RPMs) of an
existing air moving device. However, this approach is becoming
problematic at the rack level in the context of a data center.
BRIEF SUMMARY
[0004] In one aspect, the shortcomings of the prior art are
overcome and additional advantages are provided through the
provision of an apparatus for facilitating cooling of an electronic
component. The apparatus includes: a refrigerant evaporator, a
refrigerant loop, a compressor, a refrigerant bypass pipe, a
control valve and a controllable refrigerant heater. The
refrigerant evaporator is in thermal communication with the
electronic component, and includes at least one channel therein for
accommodating flow of refrigerant therethrough. The refrigerant
loop is coupled in fluid communication with the at least one
channel of the refrigerant evaporator to facilitate flow of
refrigerant through the evaporator, and the compressor is coupled
in fluid communication with the refrigerant loop. The refrigerant
bypass pipe is coupled to the refrigerant loop in parallel fluid
communication with the refrigerant evaporator, and the control
valve controls refrigerant flow through the at least one channel of
the evaporator. The control valve facilitates maintaining
temperature of the electronic component within a specified
temperature range, and the controllable refrigerant heater is
disposed to heat refrigerant passing through the refrigerant loop
to ensure that refrigerant in the refrigerant loop entering the
compressor is in a superheated thermodynamic state.
[0005] In another aspect, a cooled electronic system is provided
which includes an electronic component, and an apparatus for
facilitating cooling of the electronic component. The apparatus
includes: a refrigerant evaporator, a refrigerant loop, a
compressor, a refrigerant bypass pipe, a control valve and a
controllable refrigerant heater. The refrigerant evaporator is in
thermal communication with the electronic component, and includes
at least one channel therein for accommodating flow of refrigerant
through the evaporator. The refrigerant loop is coupled in fluid
communication with the at least one channel of the refrigerant
evaporator to facilitate flow of refrigerant through the evaporator
and the compressor is coupled in fluid communication with the
refrigerant loop. The refrigerant bypass pipe is coupled to the
refrigerant loop in parallel fluid communication with the
refrigerant evaporator, and the control valve controls refrigerant
flow through the at least one channel of the evaporator. The
control valve facilitates maintaining temperature of the electronic
component within a specified temperature range, and the
controllable refrigerant heater is controlled to heat refrigerant
passing through the refrigerant loop to ensure that refrigerant in
the refrigerant loop entering the compressor is in a superheated
thermodynamic state.
[0006] In a further aspect, a method of facilitating cooling of an
electronic component is provided. The method includes: coupling in
thermal communication a refrigerant evaporator to the electronic
component, the refrigerant evaporator comprising at least one
channel therein for accommodating flow of refrigerant therethrough;
providing a refrigerant loop in fluid communication with the at
least one channel of the refrigerant evaporator for facilitating
flow of refrigerant therethrough; coupling a compressor in fluid
communication with the refrigerant loop; providing a refrigerant
bypass pipe coupled to the refrigerant loop in parallel fluid
communication with the refrigerant evaporator; providing a control
valve for controlling refrigerant flow through the at least one
channel of the refrigerant evaporator, the control valve being
controlled to maintain temperature of the electronic component
within a specified temperature range; and associating a
controllable refrigerant heater in thermal communication with
refrigerant in the refrigerant loop, the controllable refrigerant
heater being controlled to selectively heat refrigerant in the
refrigerant loop to ensure that refrigerant entering the compressor
is in a superheated thermodynamic state.
[0007] Additional features and advantages are realized through the
techniques of the present invention. Other embodiments and aspects
of the invention are described in detail herein and are considered
a part of the claimed invention.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0008] One or more aspects of the present invention are
particularly pointed out and distinctly claimed as examples in the
claims at the conclusion of the specification. The foregoing and
other objects, features, and advantages of the invention are
apparent from the following detailed description taken in
conjunction with the accompanying drawings in which:
[0009] FIG. 1 depicts one embodiment of a conventional raised floor
layout of an air-cooled data center;
[0010] FIG. 2A is an isometric view of one embodiment of a modular
refrigeration unit (MRU) and its quick connects for attachment to a
cold plate and/or evaporator disposed within an electronics rack to
cool one or more electronic components (e.g., modules) thereof, in
accordance with an aspect of the present invention;
[0011] FIG. 2B is a schematic of one embodiment of a
vapor-compression refrigeration system for cooling an evaporator
(or cold plate) coupled to a high heat flux electronic component
(e.g., module) to be cooled, in accordance with an aspect of the
present invention;
[0012] FIG. 3 is an schematic of an alternate embodiment of a
vapor-compression refrigeration system for cooling multiple
evaporators coupled to respective electronic components to be
cooled, in accordance with an aspect of the present invention;
[0013] FIG. 4 is a schematic of one embodiment of a
vapor-compression refrigeration apparatus for cooling one or more
evaporators coupled to respective electronic components to be
cooled, in accordance with an aspect of the present invention;
[0014] FIG. 5A is a flowchart of one embodiment of a process for
ensuring that a specified heat load is dissipated to refrigerant
passing through the refrigerant loop of the vapor-compression
refrigeration apparatus of FIG. 4, in accordance with an aspect of
the present invention;
[0015] FIG. 5B is a flowchart of one embodiment of a process for
maintaining refrigerant entering the compressor of the
vapor-compression refrigeration apparatus in FIG. 4 in a
superheated thermodynamic state, in accordance with an aspect of
the present invention;
[0016] FIG. 6 is a schematic of another embodiment of a
vapor-compression refrigeration apparatus for cooling one or more
evaporators coupled to respective electronic components to be
cooled, in accordance with an aspect of the present invention;
[0017] FIG. 7 is a schematic of a further embodiment of a
vapor-compression refrigeration apparatus for cooling one or more
evaporators coupled to respective electronic components to be
cooled, in accordance with an aspect of the present invention;
[0018] FIG. 8 is a flowchart of one embodiment of a process for
maintaining monitored temperature of an electronic component being
cooled within a specified temperature range using the
vapor-compression refrigeration apparatus of FIG. 7, in accordance
with an aspect of the present invention; and
[0019] FIG. 9 depicts one embodiment of a computer program product
incorporating one or more aspects of the present invention.
DETAILED DESCRIPTION
[0020] As used herein, the terms "electronics rack", "rack-mounted
electronic equipment", and "rack unit" are used interchangeably,
and unless otherwise specified include any housing, frame, rack,
compartment, blade server system, etc., having one or more heat
generating components of a computer system or electronics system,
and may be, for example, a stand alone computer processor having
high, mid or low end processing capability. In one embodiment, an
electronics rack may comprise multiple electronic subsystems, each
having one or more heat generating components disposed therein
requiring cooling. "Electronic subsystem" refers to any
sub-housing, blade, book, drawer, node, compartment, etc., having
one or more heat generating electronic components disposed therein.
Each electronic subsystem of an electronics rack may be movable or
fixed relative to the electronics rack, with rack-mounted
electronics drawers of a multi-drawer rack unit and blades of a
blade center system being two examples of subsystems of an
electronics rack to be cooled.
[0021] "Electronic component" refers to any heat generating
electronic component or module of, for example, a computer system
or other electronic unit requiring cooling. By way of example, an
electronic component may comprise one or more integrated circuit
dies and/or other electronic devices to be cooled, including one or
more processor dies, memory dies and memory support dies. As a
further example, the electronic component may comprise one or more
bare dies or one or more packaged dies disposed on a common
carrier.
[0022] As used herein, "refrigerant-to-air heat exchanger" means
any heat exchange mechanism characterized as described herein
through which refrigerant coolant can circulate; and includes, one
or more discrete refrigerant-to-air heat exchangers coupled either
in series or in parallel. A refrigerant-to-air heat exchanger may
comprise, for example, one or more coolant flow paths, formed of
thermally conductive tubing (such as copper or other tubing) in
thermal or mechanical contact with a plurality of air-cooled
cooling or condensing fins. Size, configuration and construction of
the refrigerant-to-air heat exchanger can vary without departing
from the scope of the invention disclosed herein.
[0023] Unless otherwise specified, "refrigerant evaporator" refers
to a heat-absorbing mechanism or structure within a refrigeration
loop. The refrigerant evaporator is alternatively referred to as a
"sub-ambient evaporator" when temperature of the refrigerant
passing through the refrigerant evaporator is below the temperature
of ambient air entering the electronics rack. Within the
refrigerant evaporator, heat is absorbed by evaporating the
refrigerant of the refrigerant loop. Still further, "data center"
refers to a computer installation containing one or more
electronics racks to be cooled. As a specific example, a data
center may include one or more rows of rack-mounted computing
units, such as server units.
[0024] As used herein, the phrase "controllable refrigerant heater"
refers to an adjustable heater which allows active control of an
auxiliary heat load applied to refrigerant passing through the
refrigerant loop of a cooling apparatus, such as described herein.
In one example, the controllable refrigerant heater comprises one
or more electrical resistance elements in thermal communication
with the refrigerant passing through the refrigerant loop and
powered by an electrical power source.
[0025] One example of the refrigerant employed in the examples
below is R134a refrigerant. However, the concepts disclosed herein
are readily adapted to use with other types of refrigerant. For
example, the refrigerant may alternatively comprise R245fa, R404,
R12, or R22 refrigerant.
[0026] Reference is made below to the drawings, which are not drawn
to scale for ease of understanding, wherein the same reference
numbers used throughout different figures designate the same or
similar components.
[0027] FIG. 1 depicts a raised floor layout of an air cooled data
center 100 typical in the prior art, wherein multiple electronics
racks 110 are disposed in one or more rows. A data center such as
depicted in FIG. 1 may house several hundred, or even several
thousand microprocessors. In the arrangement illustrated, chilled
air enters the computer room via perforated floor tiles 160 from a
supply air plenum 145 defined between the raised floor 140 and a
base or sub-floor 165 of the room. Cooled air is taken in through
louvered or screened doors at air inlet sides 120 of the
electronics racks and expelled through the back (i.e., air outlet
sides 130) of the electronics racks. Each electronics rack 110 may
have one or more air moving devices (e.g., fans or blowers) to
provide forced inlet-to-outlet airflow to cool the electronic
components within the drawer(s) of the rack. The supply air plenum
145 provides conditioned and cooled air to the air-inlet sides of
the electronics racks via perforated floor tiles 160 disposed in a
"cold" aisle of the computer installation. The conditioned and
cooled air is supplied to plenum 145 by one or more air
conditioning units 150, also disposed within the data center 100.
Room air is taken into each air conditioning unit 150 near an upper
portion thereof. This room air comprises in part exhausted air from
the "hot" aisles of the computer installation defined by opposing
air outlet sides 130 of the electronics racks 110.
[0028] In high performance server systems, it has become desirable
to supplement air-cooling of selected high heat flux electronic
components, such as the processor modules, within the electronics
rack. For example, the System z.RTM. server marketed by
International Business Machines Corporation, of Armonk, N.Y.,
employs a vapor-compression refrigeration cooling system to
facilitate cooling of the processor modules within the electronics
rack. This refrigeration system employs R134a refrigerant as the
coolant, which is supplied to a refrigerant evaporator coupled to
one or more processor modules to be cooled. The refrigerant is
provided by a modular refrigeration unit (MRU), which supplies the
refrigerant at an appropriate temperature.
[0029] FIG. 2A depicts one embodiment of a modular refrigeration
unit 200, which may be employed within an electronic rack, in
accordance with an aspect of the present invention. As illustrated,
modular refrigeration unit 200 includes refrigerant supply and
exhaust hoses 201 for coupling to a refrigerant evaporator or cold
plate (not shown), as well as quick connect couplings 202, which
respectively connect to corresponding quick connect couplings on
either side of the refrigerant evaporator, that is coupled to the
electronic component(s) or module(s) (e.g., server module(s)) to be
cooled. Further details of a modular refrigeration unit such as
depicted in FIG. 2A are provided in commonly assigned U.S. Pat. No.
5,970,731.
[0030] FIG. 2B is a schematic of one embodiment of modular
refrigeration unit 200 of FIG. 2A, coupled to a refrigerant
evaporator for cooling, for example, an electronic component within
an electronic subsystem of an electronics rack. The electronic
component may comprise, for example, a multichip module, a
processor module, or any other high heat flux electronic component
(not shown) within the electronics rack. As illustrated in FIG. 2B,
a refrigerant evaporator 260 is shown that is coupled to the
electronic component (not shown) to be cooled and is connected to
modular refrigeration unit 200 via respective quick connect
couplings 202. Within modular refrigeration unit 200, a motor 221
drives a compressor 220, which is connected to a condenser 230 by
means of a supply line 222. Likewise, condenser 230 is connected to
evaporator 260 by means of a supply line which passes through a
filter/dryer 240, which functions to trap particulate matter
present in the refrigerant stream and also to remove any water
which may have become entrained in the refrigerant flow. Subsequent
to filter/dryer 240, refrigerant flow passes through an expansion
device 250. Expansion device 250 may be an expansion valve.
However, it may also comprise a capillary tube or thermostatic
valve. Thus, expanded and cooled refrigerant is supplied to
evaporator 260. Subsequent to the refrigerant picking up heat from
the electronic component coupled to evaporator 260, the refrigerant
is returned via an accumulator 210 which operates to prevent liquid
from entering compressor 220. Accumulator 210 is also aided in this
function by the inclusion of a smaller capacity accumulator 211,
which is included to provide an extra degree of protection against
the entry of liquid-phase refrigerant into compressor 220.
Subsequent to accumulator 210, vapor-phase refrigerant is returned
to compressor 220, where the cycle repeats. In addition, the
modular refrigeration unit is provided with a hot gas bypass valve
225 in a bypass line 223 selectively passing hot refrigerant gasses
from compressor 220 directly to evaporator 260. The hot gas bypass
valve is controllable in response to the temperature of evaporator
260, which is provided by a module temperature sensor (not shown),
such as a thermistor device affixed to the evaporator/cold plate in
any convenient location. In one embodiment, the hot gas bypass
valve is electronically controlled to shunt hot gas directly to the
evaporator when temperature is already sufficiently low. In
particular, under low temperature conditions, motor 221 runs at a
lower speed in response to the reduced thermal load. At these lower
speeds and loads, there is a risk of motor 221 stalling. Upon
detection of such a condition, the hot gas bypass valve is opened
in response to a signal supplied to it from a controller of the
modular refrigeration unit.
[0031] FIG. 3 depicts an alternate embodiment of a modular
refrigeration unit 300, which may be employed within an electronics
rack, in accordance with an aspect of the present invention.
Modular refrigeration unit 300 includes (in this example) two
refrigerant loops 305, or i.e., sets of refrigerant supply and
exhaust hoses, coupled to respective refrigerant evaporators (or
cold plates) 360 via quick connect couplings 302. Each refrigerant
evaporator 360 is in thermal communication with a respective
electronic component 301 (e.g., multichip module (MCM)) for
facilitating cooling thereof. Refrigerant loops 305 are
independent, and shown to include a compressor 320, a respective
condenser section of a shared condenser 330 (i.e., a
refrigerant-to-air heat exchanger), and an expansion (and flow
control) valve 350, which is employed by a controller 340 to
maintain temperature of the electronic component at a steady
temperature level, e.g., 29.degree. C. In one embodiment, the
expansion valves 350 are controlled by controller 340 with
reference to temperature of the respective electronic component 301
T.sub.MCM1, T.sub.MCM2. The refrigerant and coolant loops may also
contain further sensors, such as sensors for condenser air
temperature IN T1, condenser air temperature OUT T2, temperature
T3, T3' of high-pressure liquid refrigerant flowing from the
condenser 330 to the respective expansion valve 350, temperature
T4, T4' of high-pressure refrigerant vapor flowing from each
compressor 320 to the respective condenser section 330, temperature
T6, T6' of low-pressure liquid refrigerant flowing from each
expansion valve 350 into the respective evaporator 360, and
temperature T7, T7' of low-pressure vapor refrigerant flowing from
the respective evaporator 360 towards the compressor 320. Note that
in this implementation, the expansion valves 350 operate to
actively throttle the pumped refrigerant flow rate, as well as to
function as expansion orifices to reduce the temperature and
pressure of refrigerant passing through it.
[0032] In situations where electronic component 301 temperature
decreases (i.e., the heat load decreases), the respective expansion
valve 350 is partially closed to reduce the refrigerant flow
passing through the associated evaporator 360 in an attempt to
control temperature of the electronic component. If temperature of
the component increases (i.e., heat load increases), then the
controllable expansion valve 350 is opened further to allow more
refrigerant flow to pass through the associated evaporator, thus
providing increased cooling to the component. In extreme
conditions, there is the possibility of too much refrigerant flow
being allowed to pass through the evaporator, possibly resulting in
partially-evaporated fluid, (i.e., liquid-vapor mixture) being
returned to the respective compressor, which can result in
compressor valve failure due to out-of-specification pressures
being imposed on the compressor valve. There is also the
possibility of particulate and chemical contamination over time
resulting from oil break-down inside the loop accumulating within
the controllable expansion valve. Accumulation of contamination
within the valve can lead to both valve clogging and erratic valve
behavior.
[0033] In accordance with another aspect of the present invention,
FIG. 4 depicts an alternate implementation of a vapor-compression
refrigeration apparatus which does not require a mechanical flow
control and adjustable expansion valve, such as described above in
connection with the modular refrigeration unit of FIG. 3, and which
ensures that the refrigerant fluid enters the compressor in a
superheated thermodynamic state. In the embodiment of FIG. 4 a
dual-loop, cooled electronic system is depicted by way of example
only. Those skilled in the art should note that the
vapor-compression refrigeration apparatus depicted therein and
described below can readily be configured for cooling a single
electronic component, or a plurality of electronic components
(either with or without employing a shared condenser, as in the
example of FIG. 4).
[0034] As shown in FIG. 4, cooled electronic system 400 includes an
electronics rack 401 which comprises multiple electronic components
405 to be cooled. By way of specific example only, each electronic
component 405 to be cooled by the cooling apparatus may be a
multichip module (MCM), such as a processor MCM. In the illustrated
implementation, the cooling apparatus is a vapor-compression
refrigeration apparatus with a controlled refrigerant heat load. As
illustrated, a refrigerant evaporator 410 is associated with a
respective electronic component 405 to be cooled, a refrigerant
loop 420 is coupled in fluid communication with refrigerant
evaporator 410, to allow for the ingress and egress of refrigerant
through the structure, and quick connect couplings 402 facilitate
coupling of refrigerant evaporator 410 to the remainder of the
cooling apparatus. Each refrigerant loop 420 is also in fluid
communication with a respective compressor 440, a condenser section
passing through a shared condenser 450, and a filter/dryer (not
shown). In the embodiment illustrated, each refrigerant loop 420
includes a fixed orifice expansion valve 411 associated with the
respective refrigerant evaporator 410 and disposed, for example, at
a refrigerant inlet to the refrigerant evaporator 410. An
air-moving device 451 facilitates airflow across shared condenser
450. Note that, in an alternate implementation, each refrigerant
loop of the vapor-compression compression refrigeration apparatus
could incorporate its own condenser and air-moving device.
[0035] The vapor-compression refrigeration apparatus further
includes an auxiliary evaporator 430 and an auxiliary heater 435
associated and in thermal communication therewith. In this example,
auxiliary evaporator 430 is in thermal communication with
refrigerant loop 420 and may comprise, for example, a thermally
conductive structure comprising one or more refrigerant channels
passing therethrough in fluid communication with refrigerant loop
420. Auxiliary evaporator 430 and auxiliary heater 435 together
comprise a controllable refrigerant heater which is in thermal
communication with refrigerant passing through refrigerant loop 420
for controllably applying an auxiliary heat load thereto, as
described further below. Note that, depending upon the
implementation, auxiliary evaporator 430 and auxiliary heater 435
may be distinct structures or be fabricated or assembled as an
integrated structure.
[0036] A controller 460 is provided electrically coupled to the
controllable refrigerant heaters, refrigerant temperature and
pressure sensors T.sub.R, P.sub.R, and MCM heat load sensors QMCM
for facilitating control of the vapor-compression refrigeration
process within each cooling apparatus, as described further below
with reference to the control processes of FIGS. 5A & 5B. Each
controllable refrigerant heater is associated with and in thermal
communication with a respective refrigerant loop 420 to apply a
desired heat load to refrigerant in the refrigerant loop to ensure
that refrigerant entering the compressor is in a superheated
thermodynamic state.
[0037] In the cooling apparatus embodiment of FIG. 4, the
controllable refrigerant heaters are disposed downstream from the
associated refrigerant evaporators 410, between an outlet of the
respective refrigerant evaporator 410 and the respective compressor
440. In operation, each electronic component 405 applies a heat
load QMCM to refrigerant passing through the refrigerant evaporator
410. Refrigerant circulates through refrigerant evaporator 410 and
the controllable refrigerant heater applies an auxiliary heat load
to the refrigerant to ensure that the refrigerant entering
compressor 440 is in a superheated thermodynamic state. Heat is
rejected from the refrigerant in refrigerant loop 420 to an air
stream via the air-cooled condenser 450, and liquid refrigerant is
circulated from the condenser 450 back to the refrigerant
evaporator 410 to repeat the process. Advantageously, by ensuring
that refrigerant entering the compressor is in a superheated
thermodynamic state, the compressor 440 can work at a fixed speed,
and a fixed orifice 411 can be used within refrigerant loop 420 as
the expansion valve for the vapor-compression refrigeration
apparatus. The application of an adjustable, auxiliary heat load by
the controllable refrigerant heater to the refrigerant passing
through the loop means that a desired, specified heat load can be
maintained within the refrigerant loop, and by prespecifying this
desired specified heat load, superheated refrigerant can be
guaranteed to enter the compressor, allowing for reliable operation
of the vapor-compression refrigeration apparatus. The controllable
refrigerant heater can be controlled using a variety of approaches,
with various thermal measurements being employed and transmitted to
the controller to incrementally adjust the heat load being applied
by the controllable refrigerant heater to the circulating
refrigerant.
[0038] Advantageously, the use of a cooling apparatus such as
depicted in FIG. 4 addresses electronic component heat load changes
by, for example, maintaining a specified heat load on the
refrigerant in the refrigerant loop. The controllable refrigerant
heater may be controlled based, for example, on current heat load
provided by (or current temperature of) the electronic component,
or alternatively, based upon temperature and pressure of
refrigerant within the refrigerant loop, as respectively depicted
in FIGS. 5A & 5B. Advantageously, within the cooling apparatus,
the refrigerant loop may be hard-plumbed, and a constant speed
compressor may be advantageously employed, along with a fixed
expansion orifice. This enables a minimum amount of controls on the
refrigerant loop. The resulting cooling apparatus can be packaged
inside a modular refrigeration unit-like subassembly, such as
depicted above in connection with FIG. 2A.
[0039] Referring to FIG. 5A, substantially constant refrigerant
heating is established by first setting the heat load applied to
the refrigerant by the controllable refrigerant heater
(Q.sub.HEATER) equal to an initial (or nominal) heat load value
(Q.sub.INITIAL) 500. The current component heat load (e.g., power
data) is collected 510. If the MCM heat load (Q.sub.MCM) is less
than a desired, specified heat load (Q.sub.spec) 520, then the
controllable refrigerant heater is adjusted to apply a heat load
(Q.sub.HEATER) which matches the difference 550. Otherwise, the
heat load applied by the controllable refrigerant heater
(Q.sub.HEATER) is set to zero 530. After adjusting the heat load,
processing waits a defined time (t) 540 before repeating the
process by again collecting current component heat load data
(Q.sub.MCM) 510.
[0040] In operation, heat load input to the refrigerant in the
refrigerant loop by the auxiliary controllable refrigerant heater
will typically be equal to the difference between the specified
electronic component heat load (e.g., the rated or maximum
electronic component power) and the actual current electronic
component heat load (e.g., current component power). Thus, if the
electronic component is fully loaded and is running at full rated
load, then the controllable refrigerant heater is OFF. In the event
that the electronic component is intrinsically running at a lower
power, or if the computational activity of the electronic component
is reduced, thereby reducing the electronic component load, then
the controllable refrigerant heater is ON and supplying power (or
heat load) to the refrigerant loop that is equal to the difference,
as described above. In this manner, the loading on the refrigerant
loop is maintained at a relatively constant, stable value, which
ensures that the compressor always receives superheated vapor by
design.
[0041] FIG. 5B depicts an alternate control process which ensures
that refrigerant entering the compressor is in a superheated
thermodynamic state. In this approach, measurements of refrigerant
temperature and refrigerant pressure at the inlet of the compressor
are used to control the amount of heat load (or power) delivered by
the auxiliary, controllable refrigerant heater. This advantageously
allows for a stable electronic component temperature, while
ensuring that superheated vapor is received into the compressor.
This in turn advantageously results in the elimination of the use
of any adjustable expansion valves, which might otherwise be used,
and be susceptible to fouling.
[0042] Referring to FIG. 5B, superheated thermodynamic state is
ensured by first setting the heat load applied to the refrigerant
by the controllable refrigerant heater (Q.sub.HEATER) equal to an
initial (or nominal) heat load value (Q.sub.INITIAL) 555. The
temperature of refrigerant (T.sub.R) and pressure of refrigerant
(P.sub.R) at the inlet of the compressor are collected to determine
the current thermodynamic state of the refrigerant 560. Processing
then determines whether refrigerant entering the compressor is in a
superheated state by less than or equal to a specified temperature
difference (.delta.T.sub.SPEC) from the absolute value of
refrigerant temperature at superheated condition 565. In one
example, .delta.T.sub.SPEC may be 2.degree. C. This determination
can be performed, by way of example, using a table look-up based on
known thermodynamic properties of the refrigerant. By way of
specific example, pressure (P)--enthalpy (H) diagrams for R134a
refrigerant are available in the literature which indicate the
regions in which the refrigerant is sub-cooled, saturated and
superheated. These diagrams or functions utilize variables such as
pressure and temperature (enthalpy if the quality of a two-phase
mixture needs to be known). Thus, the thermodynamic state of the
refrigerant can be determined using pressure and temperature data
and subsequently controlled using the addition of the auxiliary
heat load, if required. The pressure and temperature values
measured can be input into a refrigerant-dependent algorithm
(defined by the P-H diagram and properties of the refrigerant) that
determines if the refrigerant is superheated (or is saturated or is
in liquid phase). It is desired that the coolant entering the
compressor be slightly superheated, that is, with no liquid
content. The extent of superheat can be characterized using a
.delta.T.sub.SPEC value, which is predetermined. It is undesirable
to have a very high extent of refrigerant superheat, because this
would mean that a substantial heat load has been added to the
refrigerant, even after the refrigerant has completely changed from
liquid to gas phase. This is considered unnecessary for compressor
reliability, and would lead to highly inefficient refrigeration
loop operation. It is desired to add only as much auxiliary heat
load as needed to maintain a small degree of superheat for the
refrigerant entering the compressor to satisfy conditions for
reliable compressor operation. Therefore, if the refrigerant
entering the compressor is superheated by less than a specified
temperature difference (.delta.T.sub.SPEC), then the heat load
applied by the controllable refrigerant heater is increased by a
specified amount (.delta.Q) 570. Alternatively, if the refrigerant
entering the compressor is superheated by greater than the
specified temperature difference (.delta.T.sub.SPEC), then the heat
load applied by the controllable refrigerant heater is decreased by
the specified amount (e.g., .delta.Q) 580. After adjusting the
heater heat load, processing waits a defined time (t) 575 before
repeating the process by again collecting current thermodynamic
state data for the refrigerant, that is, refrigerant temperature
(T.sub.R) and refrigerant pressure (P.sub.R) at, for example, the
inlet to the compressor 560.
[0043] In accordance with another aspect of the present invention,
FIG. 6 depicts an alternate implementation of a vapor-compression
refrigeration apparatus such as described above in connection with
FIGS. 4-5B. Advantageously, this alternate implementation also
ensures that refrigerant entering the compressor is in a
superheated thermodynamic state. Those skilled in the art should
note that a dual-loop implementation is again depicted in FIG. 6,
by way of example only.
[0044] In FIG. 6, cooled electronic system 400' is substantially
identical to cooled electronic system 400 described above in
connection with FIG. 4, with one notable exception. In the
implementation of FIG. 6, the controllable refrigerant heaters,
each comprising one or more auxiliary evaporators 430 and one or
more auxiliary heaters 435, are each disposed in associated and
with the respective refrigerant loop 420 upstream from the
respective refrigerant evaporator 410. In such an implementation,
the controllable refrigerant heater might advantageously be
employed in the single-phase regime of the refrigerant, thereby
reducing the overall pressure drop through the controllable
refrigerant heater, and thus the refrigerant loop pressure
drop.
[0045] FIG. 7 depicts another implementation of a vapor-compression
refrigeration apparatus such as described above in connection with
FIGS. 4 & 6. Advantageously, this alternate implementation also
ensures that refrigerant fluid entering the compressor of the
refrigerant loop is in a superheated thermodynamic state. This
approach further allows for temperature of the electronic component
to be maintained within a desired specified temperature range. As
with the above examples, the dual-loop implementation depicted in
FIG. 7 is presented by way of example only.
[0046] In FIG. 7, cooled electronic system 400'' is substantially
identical to cooled electronic system 400 described above in
connection with FIG. 4, with two notable exceptions. First, a
refrigerant bypass pipe 701 is coupled to refrigerant loop 420 in
parallel fluid communication with refrigerant evaporator 410. In
this implementation, the controllable refrigerant heater comprising
auxiliary evaporator 430 and auxiliary heater 435 is associated
with and in thermal communication with refrigerant flowing through
refrigerant bypass pipe 701. As shown, refrigerant bypass pipe 701
is coupled with a first end of the bypass pipe in fluid
communication to coolant loop 420 upstream from refrigerant
evaporator 410, and a second end in fluid communication with
refrigerant loop 420 downstream from refrigerant evaporator
410.
[0047] Second, in this example, refrigerant bypass pipe 701 couples
in fluid communication with refrigerant loop 420 upstream from
refrigerant evaporator 410 through a control valve 700. In one
embodiment, control valve 700 comprises an electrically
controllable, three-way valve, which may by dynamically adjusted to
control the flow of refrigerant through refrigerant evaporator 410,
and hence, through refrigerant bypass pipe 701. The controllable
refrigerant heater associated with refrigerant bypass pipe 701 may
or may not includes a fixed expansion orifice. Whether a fixed
expansion orifice is associated with refrigerant bypass pipe 701
depends upon the refrigerant loop design.
[0048] The use of the bypass pipe advantageously allows for control
of the refrigerant flow rate through the refrigerant evaporator
410, and disposition of the auxiliary controllable refrigerant
heater in parallel fluid communication with the refrigerant
evaporator advantageously results in less overall pressure drop
through the refrigerant loop.
[0049] FIG. 8 illustrates additional control processing which may
be employed for the cooled electronic system 400'' of FIG. 7,
concurrent or simultaneous with the auxiliary heater processing of
FIG. 5A or FIG. 5B, described above. The processing of FIG. 8
utilizes knowledge of electronic component temperature (T.sub.MCM),
along with a first specified temperature (T.sub.SPEC1) and a second
specified temperature (T.sub.SPEC2), wherein temperature
T.sub.SPEC1 is higher than temperature T.sub.SPEC2. Initially, MCM
temperature control 800 begins with obtaining a current electronic
component temperature (T.sub.MCM) 805 and comparing the current
component temperature (T.sub.MCM) against the first specified
temperature (T.sub.SPEC1) 810. If the current component temperature
(T.sub.MCM) is greater than the first specified temperature
(T.sub.SPEC1), then the control valve is incrementally opened
further by a set amount (to direct more flow to the evaporator),
for example, .DELTA..theta..degree. 820, after which processing
waits a defined time (t) 825, before obtaining the then current
temperature of the component (T.sub.MCM), and repeating the
process.
[0050] Assuming that the current component temperature (T.sub.MCM)
is less than or equal to the first specified temperature
(T.sub.SPEC1), then processing determines whether the current
component temperature (T.sub.MCM) is greater than or equal to the
second specified temperature (T.sub.SPEC2) 830. If "no", then the
control valve is incrementally closed further by a set amount (to
direct more flow to the bypass pipe), for example,
.DELTA..theta..degree. 840, after which processing waits the
defined time (t) 825 before again obtaining the current temperature
of the component (T.sub.MCM) 805. Thus, with the processing of FIG.
8, and the adjusting the control valve, the component temperature
(T.sub.MCM) is controlled to be within a specified temperature
range (i.e., between (T.sub.SPEC1) and (T.sub.SPEC2)). Note that
this control can be advantageously simultaneous, or concurrent,
with ensuring that refrigerant entering the compressor of the
refrigerant loop is in a superheated thermodynamic state, for
example, in accordance with the processes of FIGS. 5A or 5B.
[0051] Note that the actual value of refrigerant loading may change
from loop to loop based (for example) on the exact value of the
electronic component to refrigerant thermal resistance. The
refrigerant evaporator and interface thermal resistance can vary
due to manufacturing tolerance, and can change over time if thermal
interface material degrades. Ultimately, the heat load dissipated
to the refrigerant is designed to be constant (or within a narrow
range), allowing the use of a fixed compressor speed, and a fixed
orifice opening as expansion valve for the refrigerant loop.
[0052] As will be appreciated by one skilled in the art, aspects of
the present invention may be embodied as a system, method or
computer program product. Accordingly, aspects of the present
invention may take the form of an entirely hardware embodiment, an
entirely software embodiment (including firmware, resident
software, micro-code, etc.) or an embodiment combining software and
hardware aspects that may all generally be referred to herein as a
"circuit," "module" or "system". Furthermore, aspects of the
present invention may take the form of a computer program product
embodied in one or more computer readable medium(s) having computer
readable program code embodied thereon.
[0053] Any combination of one or more computer readable medium(s)
may be utilized. The computer readable medium may be a computer
readable signal medium or a computer readable storage medium. A
computer readable signal medium may include a propagated data
signal with computer readable program code embodied therein, for
example, in baseband or as part of a carrier wave. Such a
propagated signal may take any of a variety of forms, including,
but not limited to, electro-magnetic, optical or any suitable
combination thereof. A computer readable signal medium may be any
computer readable medium that is not a computer readable storage
medium and that can communicate, propagate, or transport a program
for use by or in connection with an instruction execution system,
apparatus or device.
[0054] A computer readable storage medium may be, for example, but
not limited to, an electronic, magnetic, optical, electromagnetic,
infrared or semiconductor system, apparatus, or device, or any
suitable combination of the foregoing. More specific examples (a
non-exhaustive list) of the computer readable storage medium
include the following: an electrical connection having one or more
wires, a portable computer diskette, a hard disk, a random access
memory (RAM), a read-only memory (ROM), an erasable programmable
read-only memory (EPROM or Flash memory), an optical fiber, a
portable compact disc read-only memory (CD-ROM), an optical storage
device, a magnetic storage device, or any suitable combination of
the foregoing. In the context of this document, a computer readable
storage medium may be any tangible medium that can contain or store
a program for use by or in connection with an instruction execution
system, apparatus, or device.
[0055] Referring now to FIG. 9, in one example, a computer program
product 900 includes, for instance, one or more computer readable
storage media 902 to store computer readable program code means or
logic 904 thereon to provide and facilitate one or more aspects of
the present invention.
[0056] Program code embodied on a computer readable medium may be
transmitted using an appropriate medium, including but not limited
to wireless, wireline, optical fiber cable, RF, etc., or any
suitable combination of the foregoing.
[0057] Computer program code for carrying out operations for
aspects of the present invention may be written in any combination
of one or more programming languages, including an object oriented
programming language, such as Java, Smalltalk, C++ or the like, and
conventional procedural programming languages, such as the "C"
programming language, assembler or similar programming languages.
The program code may execute entirely on the user's computer,
partly on the user's computer, as a stand-alone software package,
partly on the user's computer and partly on a remote computer or
entirely on the remote computer or server. In the latter scenario,
the remote computer may be connected to the user's computer through
any type of network, including a local area network (LAN) or a wide
area network (WAN), or the connection may be made to an external
computer (for example, through the Internet using an Internet
Service Provider).
[0058] Aspects of the present invention are described herein with
reference to flowchart illustrations and/or block diagrams of
methods, apparatus (systems) and computer program products
according to embodiments of the invention. It will be understood
that each block of the flowchart illustrations and/or block
diagrams, and combinations of blocks in the flowchart illustrations
and/or block diagrams, can be implemented by computer program
instructions. These computer program instructions may be provided
to a processor of a general purpose computer, special purpose
computer, or other programmable data processing apparatus to
produce a machine, such that the instructions, which execute via
the processor of the computer or other programmable data processing
apparatus, create means for implementing the functions/acts
specified in the flowchart and/or block diagram block or
blocks.
[0059] These computer program instructions may also be stored in a
computer readable medium that can direct a computer, other
programmable data processing apparatus, or other devices to
function in a particular manner, such that the instructions stored
in the computer readable medium produce an article of manufacture
including instructions which implement the function/act specified
in the flowchart and/or block diagram block or blocks.
[0060] The computer program instructions may also be loaded onto a
computer, other programmable data processing apparatus, or other
devices to cause a series of operational steps to be performed on
the computer, other programmable apparatus or other devices to
produce a computer implemented process such that the instructions
which execute on the computer or other programmable apparatus
provide processes for implementing the functions/acts specified in
the flowchart and/or block diagram block or blocks.
[0061] The flowchart and block diagrams in the figures illustrate
the architecture, functionality, and operation of possible
implementations of systems, methods and computer program products
according to various embodiments of the present invention. In this
regard, each block in the flowchart or block diagrams may represent
a module, segment, or portion of code, which comprises one or more
executable instructions for implementing the specified logical
function(s). It should also be noted that, in some alternative
implementations, the functions noted in the block may occur out of
the order noted in the figures. For example, two blocks shown in
succession may, in fact, be executed substantially concurrently, or
the blocks may sometimes be executed in the reverse order,
depending upon the functionality involved. It will also be noted
that each block of the block diagrams and/or flowchart
illustration, and combinations of blocks in the block diagrams
and/or flowchart illustration, can be implemented by special
purpose hardware-based systems that perform the specified functions
or acts, or combinations of special purpose hardware and computer
instructions.
[0062] In addition to the above, one or more aspects of the present
invention may be provided, offered, deployed, managed, serviced,
etc. by a service provider who offers management of customer
environments. For instance, the service provider can create,
maintain, support, etc. computer code and/or a computer
infrastructure that performs one or more aspects of the present
invention for one or more customers. In return, the service
provider may receive payment from the customer under a subscription
and/or fee agreement, as examples. Additionally or alternatively,
the service provider may receive payment from the sale of
advertising content to one or more third parties.
[0063] In one aspect of the present invention, an application may
be deployed for performing one or more aspects of the present
invention. As one example, the deploying of an application
comprises providing computer infrastructure operable to perform one
or more aspects of the present invention.
[0064] As a further aspect of the present invention, a computing
infrastructure may be deployed comprising integrating computer
readable code into a computing system, in which the code in
combination with the computing system is capable of performing one
or more aspects of the present invention.
[0065] As yet a further aspect of the present invention, a process
for integrating computing infrastructure comprising integrating
computer readable code into a computer system may be provided. The
computer system comprises a computer readable medium, in which the
computer medium comprises one or more aspects of the present
invention. The code in combination with the computer system is
capable of performing one or more aspects of the present
invention.
[0066] Although various embodiments are described above, these are
only examples. For example, computing environments of other
architectures can incorporate and use one or more aspects of the
present invention. Additionally, the network of nodes can include
additional nodes, and the nodes can be the same or different from
those described herein. Also, many types of communications
interfaces may be used. Further, other types of programs and/or
other optimization programs may benefit from one or more aspects of
the present invention, and other resource assignment tasks may be
represented. Resource assignment tasks include the assignment of
physical resources. Moreover, although in one example, the
partitioning minimizes communication costs and convergence time, in
other embodiments, the cost and/or convergence time may be
otherwise reduced, lessened, or decreased.
[0067] Further, other types of computing environments can benefit
from one or more aspects of the present invention. As an example,
an environment may include an emulator (e.g., software or other
emulation mechanisms), in which a particular architecture
(including, for instance, instruction execution, architected
functions, such as address translation, and architected registers)
or a subset thereof is emulated (e.g., on a native computer system
having a processor and memory). In such an environment, one or more
emulation functions of the emulator can implement one or more
aspects of the present invention, even though a computer executing
the emulator may have a different architecture than the
capabilities being emulated. As one example, in emulation mode, the
specific instruction or operation being emulated is decoded, and an
appropriate emulation function is built to implement the individual
instruction or operation.
[0068] In an emulation environment, a host computer includes, for
instance, a memory to store instructions and data; an instruction
fetch unit to fetch instructions from memory and to optionally,
provide local buffering for the fetched instruction; an instruction
decode unit to receive the fetched instructions and to determine
the type of instructions that have been fetched; and an instruction
execution unit to execute the instructions. Execution may include
loading data into a register from memory; storing data back to
memory from a register; or performing some type of arithmetic or
logical operation, as determined by the decode unit. In one
example, each unit is implemented in software. For instance, the
operations being performed by the units are implemented as one or
more subroutines within emulator software.
[0069] Further, a data processing system suitable for storing
and/or executing program code is usable that includes at least one
processor coupled directly or indirectly to memory elements through
a system bus. The memory elements include, for instance, local
memory employed during actual execution of the program code, bulk
storage, and cache memory which provide temporary storage of at
least some program code in order to reduce the number of times code
must be retrieved from bulk storage during execution.
[0070] Input/Output or I/O devices (including, but not limited to,
keyboards, displays, pointing devices, DASD, tape, CDs, DVDs, thumb
drives and other memory media, etc.) can be coupled to the system
either directly or through intervening I/O controllers. Network
adapters may also be coupled to the system to enable the data
processing system to become coupled to other data processing
systems or remote printers or storage devices through intervening
private or public networks. Modems, cable modems, and Ethernet
cards are just a few of the available types of network
adapters.
[0071] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the invention. As used herein, the singular forms "a", "an" and
"the" are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood
that the terms "comprises" and/or "comprising", when used in this
specification, specify the presence of stated features, integers,
steps, operations, elements, and/or components, but do not preclude
the presence or addition of one or more other features, integers,
steps, operations, elements, components and/or groups thereof.
[0072] The corresponding structures, materials, acts, and
equivalents of all means or step plus function elements in the
claims below, if any, are intended to include any structure,
material, or act for performing the function in combination with
other claimed elements as specifically claimed. The description of
the present invention has been presented for purposes of
illustration and description, but is not intended to be exhaustive
or limited to the invention in the form disclosed. Many
modifications and variations will be apparent to those of ordinary
skill in the art without departing from the scope and spirit of the
invention. The embodiment was chosen and described in order to best
explain the principles of the invention and the practical
application, and to enable others of ordinary skill in the art to
understand the invention for various embodiment with various
modifications as are suited to the particular use contemplated.
* * * * *