U.S. patent application number 14/055214 was filed with the patent office on 2014-10-09 for method and system for hybrid cooling systems.
The applicant listed for this patent is Clifford A. Finley, William A. Gast, JR.. Invention is credited to Clifford A. Finley, William A. Gast, JR..
Application Number | 20140298834 14/055214 |
Document ID | / |
Family ID | 51653514 |
Filed Date | 2014-10-09 |
United States Patent
Application |
20140298834 |
Kind Code |
A1 |
Gast, JR.; William A. ; et
al. |
October 9, 2014 |
METHOD AND SYSTEM FOR HYBRID COOLING SYSTEMS
Abstract
Systems and methods are provided for a hybrid cooling system is
provided that includes a load center with a load center inlet and a
load center outlet. The system also includes a condenser that has a
condenser inlet and a condenser outlet. The load center outlet is
fluidically coupled to the condenser inlet. The system further
includes a cooling tower that has a cooling tower inlet and a
cooling tower outlet. The condenser outlet is fluidically coupled
to the cooling tower inlet. The system includes an evaporator that
has an evaporator inlet and an evaporator outlet. The cooling tower
outlet is fluidically coupled to the evaporator inlet, and the
evaporator outlet is fluidically coupled to the load center
inlet.
Inventors: |
Gast, JR.; William A.;
(Austin, TX) ; Finley; Clifford A.; (Austin,
TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Gast, JR.; William A.
Finley; Clifford A. |
Austin
Austin |
TX
TX |
US
US |
|
|
Family ID: |
51653514 |
Appl. No.: |
14/055214 |
Filed: |
October 16, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61808091 |
Apr 3, 2013 |
|
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|
Current U.S.
Class: |
62/119 ; 62/180;
62/186; 62/190; 62/513 |
Current CPC
Class: |
H05K 7/20836 20130101;
F25B 25/00 20130101; F25B 41/00 20130101; H05K 7/20827 20130101;
F25B 2500/26 20130101; H05K 7/20745 20130101 |
Class at
Publication: |
62/119 ; 62/513;
62/186; 62/190; 62/180 |
International
Class: |
F25B 49/00 20060101
F25B049/00 |
Claims
1. A hybrid cooling system comprising: a load center including a
load center inlet and a load center outlet; a condenser including a
condenser inlet and a condenser outlet, the load center outlet
fluidically coupled to the condenser inlet; a cooling tower
including a cooling tower inlet and a cooling tower outlet, the
condenser outlet fluidically coupled to the cooling tower inlet;
and an evaporator including an evaporator inlet and an evaporator
outlet, the cooling tower outlet fluidically coupled to the
evaporator inlet, the evaporator outlet fluidically coupled to the
load center inlet.
2. A system according to claim 1, further comprising a first valve
configured to direct a coolant from the cooling tower outlet to the
evaporator inlet and a second valve configured to direct the
coolant from the load center outlet to the condenser inlet.
3. A system according to claim 1, further comprising a variable
speed pump configured to circulate a coolant and maintain a flow
rate of the coolant.
4. A system according to claim 1, further comprising a first
temperature sensor to monitor a temperature of a coolant that exits
the cooling tower outlet.
5. A system according to claim 4, wherein the cooling tower
includes a variable speed fan configured to adjust fan speed based
on the temperature of the coolant that exits the cooling tower
outlet.
6. A system according to claim 1, wherein the cooling tower
includes a variable speed fan configured to adjust fan speed based
on a wet bulb temperature of an exterior atmosphere.
7. A system according to claim 1, further comprising a coolant that
is cooling water.
8. A cooling system comprising: a load center including a load
center inlet and a load center outlet; a condenser including a
condenser inlet and a condenser outlet; a cooling tower including a
cooling tower inlet and a cooling tower outlet; an evaporator
including an evaporator inlet and an evaporator outlet; a
temperature sensor configured to measure a temperature of a first
coolant that exits the cooling tower outlet; based on the measured
temperature being greater than a first designed temperature, the
first coolant directed from the load center outlet to the condenser
inlet, from the condenser outlet to the cooling tower inlet, from
the cooling tower outlet to the evaporator inlet; and from the
evaporator outlet to the load center inlet; and based on the
measured temperature being less than or equal to the first designed
temperature, the first coolant directed from the load center outlet
to the cooling tower inlet, and from the cooling tower outlet to
the load center inlet.
9. A system according to claim 8, further comprising: based on the
measured temperature being greater than a second designed
temperature: the first coolant directed from the cooling tower
outlet to the condenser inlet and from the condenser outlet to the
cooling tower inlet; and a second coolant directed from the
evaporator outlet to the load center inlet and from the load center
outlet to the evaporator inlet.
10. A system according to claim 8, further comprising: a first
valve configured to direct the first coolant from the cooling tower
outlet to the evaporator inlet or the load center inlet; and a
second valve configured to direct the first coolant from the load
center outlet to the condenser inlet or the cooling tower
inlet.
11. A system according to claim 9, further comprising: a third
valve configured to direct the first coolant from the cooling tower
outlet to the condenser inlet; and a fourth valve configured to
direct the second coolant from the load center outlet to the
evaporator inlet.
12. A system according to claim 8, further comprising a variable
speed pump configured to circulate the first coolant and maintain a
flow rate of the first coolant.
13. A system according to claim 9, further comprising a second
variable speed pump configured to circulate the second coolant and
maintain a flow rate of the second coolant.
14. A system according to claim 8, further comprising a variable
speed fan operating based on the measured temperature.
15. A system according to claim 8, further comprising: a
temperature sensor configured to measure a wet bulb temperature;
and a variable speed fan operating based on the measured wet bulb
temperature.
16. A method for a cooling system comprising: measuring a cooling
tower exit temperature of a first coolant; based on the measured
temperature being greater than a first designed temperature,
directing the first coolant from a load center outlet to a
condenser inlet, from a condenser outlet to a cooling tower inlet,
from a cooling tower outlet to an evaporator inlet; and from an
evaporator outlet to a load center inlet; and based on the measured
temperature being less than or equal to the first designed
temperature, directing the first coolant from the load center
outlet to the cooling tower inlet, and from the cooling tower
outlet to the load center inlet.
17. A method according to claim 16, further comprising: based on
the measured temperature being greater than a second designed
temperature: directing the first coolant from the cooling tower
outlet to the condenser inlet and from the condenser outlet to the
cooling tower inlet; and directing a second coolant from the
evaporator outlet to the load center inlet and from the load center
outlet to the evaporator inlet.
18. A method according to claim 16, further comprising: configuring
a first valve to direct the first coolant from the cooling tower
outlet to the evaporator inlet or the load center inlet; and
configuring a second valve to direct the first coolant from the
load center outlet to the condenser inlet or the cooling tower
inlet.
19. A method according to claim 17, further comprising: configuring
a third valve to direct the first coolant from the cooling tower
outlet to the condenser inlet; and configuring a fourth valve to
direct the second coolant from the load center outlet to the
evaporator inlet.
20. A method according to claim 16, further comprising configuring
a variable speed pump to circulate the first coolant and maintain a
flow rate of the first coolant.
Description
PRIORITY CLAIM
[0001] This application claims priority under 35 U.S.C. .sctn.119
to U.S. Provisional Patent Application Ser. No. 61/808,091 filed
Apr. 3, 2013. The contents of which is incorporated by reference
herein in its entirety.
TECHNICAL FIELD
[0002] The present disclosure relates in general to cooling systems
for building and process load centers, and more particularly to
hybrid cooling systems and associated methods.
BACKGROUND
[0003] Generally, cooling systems for industrial, computing,
commercial, residential, and other load centers are designed to
maintain environmental standards. For example, modern computer data
centers have servers, switches, and networking equipment that are
maintained at particular environmental temperature and humidity
ranges. As such, data centers use a significant amount of energy to
operate, and in fact, data center energy use is one of the fastest
growing segments of energy consumption in the United States. This
fact may be driving data centers, especially large data centers, to
find and use more energy efficient methods and systems.
[0004] One way in which industrial, computing, and commercial
centers may become more energy efficient may be through increasing
the efficiency of associated cooling systems. Conventional cooling
systems may include a chiller, direct expansion gas cooling,
water-side economizer, air-side economizer, or some combination of
these components. In addition, conventional cooling systems often
utilize water or glycol as a cooling medium in closed loop systems.
Alternatively, conventional cooling systems may utilize room air
cooling units, for example, placed near the server racks in a data
center. In these systems, cooling may be accomplished by the
operation of a direct expansion system, a water-side economizer
system, or the circulation of chilled water or in some cases glycol
as a cooling medium in closed loop systems.
[0005] Cooling systems, such as a free cooling system or a double
loop cooling system, may be designed to operate in a variety of
cooling scenarios and conditions including some conditions that may
exist for only a small fraction of the required cooling time in a
given year. Additionally, transitioning between types of cooling
systems, such as a free cooling system and a double loop cooling
system, may be cumbersome and difficult to achieve.
SUMMARY
[0006] In accordance with the teachings of the present disclosure,
disadvantages and problems associated with free cooling systems,
double loop cooling systems, and transitions between cooling
systems may be substantially reduced or eliminated.
[0007] In accordance with one embodiment of the present disclosure,
a hybrid cooling system is provided that includes a load center
with a load center inlet and a load center outlet. The system also
includes a condenser that has a condenser inlet and a condenser
outlet. The load center outlet is fluidically coupled to the
condenser inlet. The system further includes a cooling tower that
has a cooling tower inlet and a cooling tower outlet. The condenser
outlet is fluidically coupled to the cooling tower inlet. The
system includes an evaporator that has an evaporator inlet and an
evaporator outlet. The cooling tower outlet is fluidically coupled
to the evaporator inlet, and the evaporator outlet is fluidically
coupled to the load center inlet.
[0008] In accordance with another embodiment of the present
disclosure, a cooling system is provided that includes a load
center with a load center inlet and a load center outlet. The
system further includes a condenser that has a condenser inlet and
a condenser outlet, and a cooling tower that has a cooling tower
inlet and a cooling tower outlet. The system also includes an
evaporator that has an evaporator inlet and an evaporator outlet.
The system includes a temperature sensor configured to measure a
temperature of a first coolant that exits the cooling tower outlet.
Based on the measured temperature being greater than a first
designed temperature, the system includes that the first coolant is
directed from the load center outlet to the condenser inlet, and
from the condenser outlet to the cooling tower inlet. The first
coolant is further directed from the cooling tower outlet to the
evaporator inlet, and from the evaporator outlet to the load center
inlet. Based on the measured temperature being less than or equal
to the first designed temperature, the system includes that the
first coolant is directed from the load center outlet to the
cooling tower inlet, and from the cooling tower outlet to the load
center inlet.
[0009] In accordance with another embodiment of the present
disclosure, a method is provided for a cooling system that includes
measuring a cooling tower exit temperature of a first coolant.
Based on the measured temperature being greater than a first
designed temperature, the method includes directing the first
coolant from a load center outlet to a condenser inlet, from a
condenser outlet to a cooling tower inlet, from a cooling tower
outlet to an evaporator inlet, and from an evaporator outlet to a
load center inlet. Based on the measured temperature being less
than or equal to the first designed temperature, the method further
includes directing the first coolant from the load center outlet to
the cooling tower inlet, and from the cooling tower outlet to the
load center inlet.
[0010] Other technical advantages will be apparent to those of
ordinary skill in the art in view of the following specification,
claims, and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] A more complete understanding of the present embodiments and
advantages thereof may be acquired by referring to the following
description taken in conjunction with the accompanying drawings, in
which like reference numbers indicate like features, and
wherein:
[0012] FIG. 1 illustrates an example block diagram of an exemplary
cooling configuration that includes a free cooling system, a hybrid
cooling system, and a double loop cooling system, in accordance
with certain embodiments of the present disclosure;
[0013] FIG. 2 illustrates an example block diagram of an exemplary
cooling configuration that includes a free cooling system and a
hybrid cooling system, in accordance with certain embodiments of
the present disclosure;
[0014] FIG. 3 illustrates an example psychometric chart showing an
exemplary cooling process utilizing a hybrid cooling system, in
accordance with certain embodiments of the present disclosure;
and
[0015] FIG. 4 illustrates a flow chart for an example method for
cooling system transitions using hybrid cooling systems, in
accordance with certain embodiments of the present disclosure.
DETAILED DESCRIPTION
[0016] Preferred embodiments and their advantages are best
understood by reference to FIGS. 1-4, wherein like numbers are used
to indicate like and corresponding parts.
[0017] FIG. 1 illustrates an example block diagram of exemplary
cooling configuration 100 that includes free cooling system 102,
hybrid cooling system 104, and double loop cooling system 106, in
accordance with certain embodiments of the present disclosure.
Cooling configuration 100 may be utilized to cool load center 118.
Design and specifications relating to cooling configuration 100 may
be based on a target environment for load center 118, which may
include a designed or target temperature and a designed or target
humidity. Based on the target environment for load center 118 and
the amount of heat generated in load center 118, the incoming
coolant temperature may be specified. The specified incoming
coolant temperature may be based in part on the output of any
air-handlers providing air flow to load center 118. As an example,
a large data center may create an approximately 800 ton load and
require a target ambient air temperature between approximately
sixty-one and seventy-five degrees Fahrenheit and a humidity range
of approximately forty to fifty-five percent. This may be achieved
by providing local cooling systems, such as a data center with
chilled coolant. For example, based on the target environment for
load center 118, the specified incoming coolant temperature may be
approximately fifty-five degrees Fahrenheit. Efforts focused at
energy efficient cooling systems have included developments in
cooling systems that do not incorporate a chiller (U.S. Pub. No.
2011/0225997) and using multiple coolants with multiple loops (U.S.
Pat. No. 6,257,007).
[0018] Cooling configuration 100 may include cooling system 180
and/or processing system 126. Cooling system 180 may include
different cooling subsystems or modes of cooling. For example,
cooling system 180 may include free cooling system 102 with a
coolant flow shown by a dotted line. Cooling system 180 may further
include hybrid cooling system 104 with a coolant flow shown by a
solid line. Additionally, cooling system 180 may include double
loop cooling system 106a and 106b (collectively referred to as
double loop cooling system 106) with coolant flows shown by a
dash-dot line.
[0019] Additionally, coolant, e.g., cooling water 124 or secondary
fluid 146, circulates through cooling system 180 is at various
temperatures at different sections of cooling system 180.
Temperature measurement may be accomplished by temperature sensors
placed and configured to measure cooling water 124 and/or exterior
temperatures or wet bulb temperatures as suitable for a specific
implementation. For explanatory purposes, four relative temperature
ranges (TR) are specified. Each temperature range specified is not
absolute, but relative to the other temperature ranges. For
example, TR.sub.A may represent the coldest temperature range.
TR.sub.B may represent a cool temperature range. TR.sub.C may
represent a warm temperature range. TR.sub.D may represent a hot
temperature range. For example, TR.sub.A may correspond to
temperatures approximately fifty-five degrees Fahrenheit or lower,
TR.sub.B may correspond to temperatures approximately fifty-six to
sixty-five degrees Fahrenheit, TR.sub.C may correspond to
temperatures approximately sixty-six to seventy-five degrees
Fahrenheit, and TR.sub.D may correspond to temperatures
approximately seventy-six degrees Fahrenheit or higher.
[0020] Cooling system 180 may include cooling tower 108, one or
more tower pumps 110, filtration subsystem 112, one or more tower
valves 114, chiller subsystem 116, load center 118, one or more
center valves 120, and/or one or more system pumps 122. Components
of cooling system 180 may be fludically coupled. Cooling system 180
may include piping sections through which a fluid circulates and
that may connect components making up free cooling system 102,
hybrid cooling system 104, and/or double loop cooling system 106.
Although shown as three separate flows, fluid flowing through free
cooling system 102, hybrid cooling system 104, and/or double loop
cooling system 106 may be contained in the same pipe and/or piping
structure and may, as will be described herein, confine the same
fluid in a continuous flow.
[0021] In some embodiments, free cooling system 102 includes
cooling water 124 that circulates through a single loop of piping,
machinery, and/or other connections. Free cooling system 102 may
circulate cooling water 124 through cooling tower 108, tower pumps
110, filtration subsystem 112, tower valves 114, load center 118,
and/or center valves 120. Free cooling system 102 may further
include a chemical treatment and monitoring subsystem, a
temperature control subsystem, and/or a mechanical cooling
subsystem. Free cooling system 102 may be open to the exterior
environment at cooling tower 108.
[0022] Cooling water 124 circulating in free cooling system 102
exits cooling tower 108 through cooling tower outlet 158 in
temperature range TR.sub.A. Cooling water 124 that exits cooling
tower 108 may be at temperature T.sub.CT. For example, cooling
water 124 in free cooling system 102 may exit cooling tower 108 at
T.sub.CT equal to approximately fifty-five degrees Fahrenheit.
Cooling water 124 circulates through tower pump 110, filtration
subsystem 112, and tower valves 114 to load center inlet 168 at
approximately the same temperature, e.g. T.sub.CT. Cooling water
124 is heated a defined number of degrees, e.g. .DELTA.T.sub.L,
while circulating through load center 118. For example, cooling
water 124 may be heated a .DELTA.T.sub.L equal to approximately ten
degrees Fahrenheit as a result of the desired removal of heat from
load center 118. Thus, in the current example, cooling water 124
exiting load center 118 at load center outlet 162 may be in
temperature range TR.sub.B or temperature equal to approximately
sixty-five degrees Fahrenheit. Cooling water 124 circulates though
center valves 120 and back to cooling tower 108 to enter cooling
tower inlet 160 in temperature range TR.sub.B or temperature
approximately sixty-five degrees Fahrenheit in the current example.
Cooling water 124 circulating in free cooling system 102 circulates
through cooling tower 108 and the temperature of cooling water 124
may be lowered by .DELTA.T.sub.L. For example, cooling water 124
exiting cooling tower 108, e.g. T.sub.CT, may again be in
temperature range TR.sub.A or approximately fifty-five degrees
Fahrenheit. A .DELTA.T.sub.L of approximately ten degrees
Fahrenheit may be for ease of example and a cooling system design
may account for larger or smaller .DELTA.T.sub.L and different
inlet and exit temperatures as suitable for a particular
implementation.
[0023] In some embodiments, cooling system 180 may be configured to
operate free cooling system 102 below a target wet bulb
temperature, e.g., low humidity atmospheric air. For example, at a
wet bulb temperature below approximately fifty degrees Fahrenheit,
free cooling system 102 may be the more efficient cooling system to
operate instead of either double loop cooling system 106 or hybrid
cooling system 104. However, as the wet bulb temperature rises,
free cooling system 102 may not be capable of lowering the
temperature of cooling water 124 sufficiently to adequately cool
load center 118. For example, cooling tower 108 operating alone,
e.g., without the use of chiller 116, may be unable to lower the
temperature of cooling water 124 to approximately fifty-five
degrees Fahrenheit that may be required to adequately cool load
center 118. Thus, cooling system 180 may be configured to
transition from free cooling system 102 to either double loop
cooling system 106 or hybrid cooling system 104 when the
atmospheric conditions and/or the temperature of cooling water 124
indicate that free cooling system 102 is no longer adequately
lowering the temperature of cooling water 124.
[0024] In some embodiments, cooling system 180 may include double
loop cooling system 106. Double loop cooling system 106 may include
first loop 106a and secondary loop 106b. The inclusion of secondary
loop 106b may allow the use of coolant or secondary fluid 146 that
may be circulated separately from cooling water 124. Secondary
fluid 146 may be the medium that cools load center 118 in the case
that free cooling system 102 and/or hybrid cooling system 104 is
unable to adequately lower the temperature of cooling water 124.
However, as will be discussed herein, if hybrid cooling system 104
is to be used, the same coolant, e.g., cooling water 124, would be
used throughout.
[0025] First loop 106a may include cooling water 124 that
circulates through a loop of piping, machinery, and/or other
connections. First loop 106a may circulate cooling water 124
through cooling tower 108, tower pumps 110, filtration subsystem
112, tower valves 114, and/or condenser 138. Second loop 106b may
include secondary fluid 146. Secondary fluid 146 may be water,
glycol, Freon, refrigerant, and/or any other suitable cooling
fluid. Second loop 106b may circulate secondary fluid 146 through
evaporator 136, load center 118, center valves 120, and/or system
pumps 122.
[0026] Cooling water 124 circulating in first loop 106a exits
cooling tower 108 through cooling tower outlet 158 in temperature
range TR.sub.C. Cooling water 124 that exits cooling tower 108 may
be at temperature T.sub.CT. For example, cooling water 124 in first
loop 106a may exit cooling tower 108 at T.sub.CT equal to
approximately seventy-five degrees Fahrenheit. Cooling water 124
circulates through tower pump 110, filtration subsystem 112, and
tower valves 114 to condenser 138 at approximately the same
temperature, e.g. T.sub.CT. Cooling water 124 is heated a defined
number of degrees, e.g. .DELTA.T.sub.C, while circulating through
condenser 138. For example, cooling water 124 may be heated a
.DELTA.T.sub.C equal to approximately ten degrees Fahrenheit. Thus,
in the current example, cooling water 124 exiting condenser 138 at
condenser outlet 156 may be in temperature range TR.sub.D or at
temperature equal to approximately eighty-five degrees Fahrenheit.
Cooling water 124 circulates back to cooling tower 108 to enter
cooling tower inlet 160. Cooling water 124 may enter cooling tower
inlet 160 in temperature range TR.sub.D or approximately
eighty-five degrees Fahrenheit in the current example. Cooling
water 124 circulating in first loop 106a circulates through cooling
tower 108 and the temperature of cooling water 124 may be lowered
by .DELTA.T.sub.C. For example, cooling water 124 exiting cooling
tower 108, e.g. T.sub.CT, may again be in temperature range
TR.sub.C at approximately seventy-five degrees Fahrenheit.
[0027] In a second loop of double loop cooling system 106,
secondary fluid 146 circulating in second loop 106b exits
evaporator 136 through evaporator outlet 152. Secondary fluid 146
that exits evaporator 136 may be in temperature range TR.sub.A. For
example, secondary fluid 146 in second loop 106b may exit
evaporator 136 approximately fifty-five degrees Fahrenheit.
Secondary fluid 146 enters load center inlet 168 and is heated a
defined number of degrees, e.g. .DELTA.T.sub.L, while circulating
through load center 118. For example, secondary fluid 146 may be
heated a .DELTA.T.sub.L equal to approximately ten degrees
Fahrenheit. Thus, in the current example, secondary fluid 146
exiting load center 118 at load center outlet 162 may be in
temperature range TR.sub.B at temperature equal to approximately
sixty-five degrees Fahrenheit. Secondary fluid 146 circulates back
through center valves 120 and system pump 122 to evaporator 136 to
enter evaporator inlet 150 in temperature range TR.sub.B or
approximately sixty-five degrees Fahrenheit in the current example.
Secondary fluid 146 circulating in second loop 106b circulates
through evaporator 136 and the temperature of secondary fluid 146
may be lowered by .DELTA.T.sub.L. For example, secondary fluid 146
exiting evaporator 136 may again be in temperature range TR.sub.A
or approximately fifty-five degrees Fahrenheit.
[0028] It should be noted that double loop cooling system 106 may
require additional pumps, e.g., system pumps 122, in comparison to
free cooling system 102 and hybrid cooling system 104 in order to
separately circulate the separate fluids through first and second
loops 106a and 106b. Also, double loop cooling system 106 may
employ a chiller 116 including evaporator 136 and condenser 138 to
provide additional cooling. The use of chiller 116 may allow double
loop cooling system 106 to operate in environments with higher
temperatures, higher humidity levels and/or higher wet bulb
temperatures than free cooling system 102. As such, double loop
cooling system 106 may have higher energy requirements than free
cooling system 102. Thus, reductions in energy consumption may be
achieved by operating cooling system 180 as free cooling system 102
when environmental conditions allow and only operate double loop
cooling system 106 when necessary.
[0029] However, transitioning between free cooling system 102 and
double loop cooling system 106 may be difficult, cumbersome, and/or
involve reliability risks. In operation, chiller 116 may require a
designed lift, or temperature difference, to be present across
chiller 116 in order for chiller 116 to operate. Generally, the
lower the lift, the more efficient chiller 116 may operate.
However, the chiller design may require that the minimum lift
between the condenser outlet 156 and the evaporator outlet 152 be
approximately ten degrees Fahrenheit. If the designed lift is not
present, chiller 116 may be difficult to start and/or operate and
in particular designs, chiller 116 may not start and/or operate
without the designed lift present. When a transition between free
cooling system 102 and double loop cooling system 106 begins, the
required lift may not be present. Thus, artificial loads and other
methods of artificially generating the required lift, or
temperature difference, may have to be employed. Artificial loads
may add to the energy consumption and may reduce the overall
efficiency of cooling system 180. Consequently, transitioning
between free cooling system 102 and double loop cooling system 106
may be difficult and may require artificial loads to be generated
and placed on chiller 116 until the required lift is achieved. The
incorporation and utilization of hybrid cooling system 104 may
provide an intermediate cooling solution and may alleviate the
difficulty of cooling system transitions. This will prevent
inefficiencies associated with artificial loads and generate
overall energy savings.
[0030] Hybrid cooling system 104 may utilize the same components
described previously with a different flow pattern to provide a
third modality for cooling that may operate in a domain between
free cooling system 102 and double loop cooling system 106. In some
embodiments, hybrid cooling system 104 includes cooling water 124
that circulates through a single loop of piping, machinery, and/or
other connections. Hybrid cooling system 104 may circulate cooling
water 124 through cooling tower 108, tower pumps 110, filtration
subsystem 112, tower valves 114, evaporator 136, load center 118,
center valves 120, and/or condenser 138.
[0031] Cooling water 124 circulating in hybrid cooling system 104
exits cooling tower 108 through cooling tower outlet 158 in
temperature range TR.sub.B. Cooling water 124 that exits cooling
tower 108 may be at temperature T.sub.CT. For example, cooling
water 124 in hybrid cooling system 104 may exit cooling tower 108
at T.sub.CT equal to approximately sixty degrees Fahrenheit.
Cooling water 124 may circulate through tower pump 110, filtration
subsystem 112, and tower valves 114 to evaporator 136 at evaporator
inlet 150 at approximately the same temperature, e.g. T.sub.CT. As
cooling water 124 circulates through evaporator 136, cooling water
124 is cooled a defined number of degrees, e.g. .DELTA.T.sub.C. For
example, cooling water 124 may be cooled a .DELTA.T.sub.C equal to
approximately five degrees Fahrenheit to a temperature of
approximately fifty-five degrees Fahrenheit in temperature range
TR.sub.A. Cooling water 124 may exit evaporator 136 at evaporator
outlet 152 and circulate to load center 118 while maintaining
approximately the same temperature. Cooling water 124 is heated
.DELTA.T.sub.L as it circulates in load center 118. Thus, in the
current example, cooling water 124 exiting load center 118 at load
center outlet 162 may be in temperature range TR.sub.B or
temperature equal to approximately sixty-five degrees Fahrenheit.
Cooling water 124 circulates though center valves 120 and to
condenser 138 to enter condenser inlet 154. Cooling water 124 is
heated .DELTA.T.sub.C while circulating through condenser 138. For
example, cooling water 124 may be heated a .DELTA.T.sub.C equal to
approximately five degrees Fahrenheit. Thus, in the current
example, cooling water 124 exiting condenser 138 at condenser
outlet 156 may be in temperature range TR.sub.C or temperature
equal to approximately seventy degrees Fahrenheit. Cooling water
124 may circulate back to cooling tower 108 to enter cooling tower
inlet 160 in temperature range TR.sub.C or temperature
approximately seventy degrees Fahrenheit in the current example.
Cooling water 124 circulating in hybrid cooling system 104
circulates through cooling tower 108 and the temperature of cooling
water 124 may be lowered by .DELTA.T.sub.L. For example, cooling
water 124 exiting cooling tower 108, e.g. T.sub.CT, may again be in
temperature range TR.sub.B or approximately sixty degrees
Fahrenheit.
[0032] In some embodiments, hybrid cooling system 104 may resolve
issues associated with starting chiller 116 as discussed with
reference to double loop cooling system 106. In contrast to double
loop cooling system 106, hybrid cooling system 104 is configured to
direct cooling water 124 from tower valves 114 to evaporator inlet
150 rather than condenser inlet 154. In hybrid cooling system 104,
the temperature of cooling water 124 at evaporator inlet 150 may be
approximately the same temperature as the temperature at cooling
tower outlet 158, e.g., T.sub.CT. For example, T.sub.CT may be
approximately sixty degrees Fahrenheit. This configuration may
result in lift, or temperature difference across chiller 116, of
approximately fifteen degrees Fahrenheit. Thus, in hybrid cooling
system 104, the designed lift required across chiller 116 may be
created in a single loop. Accordingly, the incorporation of hybrid
cooling system 104 in cooling system 180 may provide an
intermediate cooling system that may address intermediate
environments and allow for less cumbersome transitions between free
and double loop cooling configurations. In addition, in this
example, the chiller may be running at approximately fifty percent
of the design load, thus saving energy.
[0033] In some embodiments, use of hybrid cooling system 104 may
allow components of cooling system 180 to be sized smaller than
required in double loop cooling system 106. For example, the same
amount of cooling may be achieved with hybrid cooling system 104
using an approximately 570 ton chiller as may be achieved with
double loop cooling system 106 using an approximately 1000 ton
chiller.
[0034] Components of cooling configuration 100 may include
processing system 126. Processing system 126 may include any
instrumentality or aggregate of instrumentalities operable to
compute, classify, process, transmit, receive, retrieve, originate,
switch, store, display, manifest, detect, record, reproduce,
handle, or utilize any form of information, intelligence, or data
for business, scientific, control, or other purposes. For example,
processing system 126 may be a personal computer, a network storage
resource, or any other suitable device and may vary in size, shape,
performance, functionality, and price.
[0035] Processing system 126 may include one or more processing
resources such as a central processing unit (CPU), microprocessor,
microcontroller, digital signal processor (DSP), application
specific integrated circuit (ASIC), or any other digital or analog
circuitry configured to interpret and/or execute program
instructions and/or process data. A processing resource may
interpret and/or execute program instructions and/or process data
stored in memory, mass storage device, and/or another component of
cooling configuration 100.
[0036] Processing system 126 may include any system, device, or
apparatus operable to retain program instructions or data for a
period of time (e.g., computer-readable media) such as hardware or
software control logic, random access memory (RAM), electrically
erasable programmable read-only memory (EEPROM), a PCMCIA card,
flash memory, magnetic storage, opto-magnetic storage, or any
suitable selection and/or array of volatile or non-volatile memory
that retains data after power to processing system 126 may be
removed.
[0037] Processing system 126 may include one or more storage
resources (or aggregations thereof) communicatively coupled to the
processing resource and may include any system, device, or
apparatus operable to retain program instructions or data for a
period of time (e.g., computer-readable media). Storage resources
may include one or more hard disk drives, magnetic tape libraries,
optical disk drives, magneto-optical disk drives, compact disk
drives, compact disk arrays, disk array controllers, solid state
drives (SSDs), and/or any computer-readable medium operable to
store data. Computer-readable media may include any instrumentality
or aggregation of instrumentalities that may retain data and/or
instructions for a period of time. Computer-readable media may
include, without limitation, storage media such as a direct access
storage device (e.g., a hard disk drive or floppy disk), a
sequential access storage device (e.g., a tape disk drive), compact
disk, CD-ROM, DVD, random access memory (RAM), read-only memory
(ROM), electrically erasable programmable read-only memory
(EEPROM), and/or flash memory; as well as communications media such
wires, optical fibers, microwaves, radio waves, and other
electromagnetic and/or optical carriers; and/or any combination of
the foregoing.
[0038] Additional components of processing system 126 may include
one or more network ports for communicating with external devices
as well as various input and output (I/O) devices, such as a
keyboard, a mouse, and a video display. Processing system 126 may
also include one or more buses or wireless devices operable to
transmit communications between the various hardware components
and/or any component of cooling system 180.
[0039] Processing system 126 may generally be operable to receive
data from, and/or transmit data to, any component of cooling system
180 and/or other processing systems. Processing system 126 may be a
host computer, a remote system, and/or any other computing system
communicatively coupled to cooling system 180. Processing system
126 may be included in load center 118 or may be remote from
cooling system 180.
[0040] Cooling tower 108 may be a high efficiency counter-flow
design with an induced draft fan. In alternate embodiments, cooling
tower 108 may utilize other designs and configurations that perform
the same or similar function. Cooling tower 108 may use an induced
draft fan to draw or blow atmospheric air through an atmospheric
air inlet 130. The induced draft fan may be a fixed speed fan or a
variable speed fan. Cooling tower 108 may be exposed to the
external atmosphere. The atmospheric air may interact with cooling
water 124 that enters cooling tower 108 via return piping section
160. As the cooling water 124 exiting the return piping section 160
mixes with the atmospheric air, the latent heat of vaporization is
absorbed from cooling water 124 and the atmospheric air. As a
result, cooling water 124 is cooled. Cooling tower 108 may
additionally include temperature sensors, flow rate meters,
pressure sensors, and/or any other suitable components to allow for
monitoring and control of cooling tower 108.
[0041] The rate and amount of cooling performed within cooling
tower 108 will depend on the wet bulb characteristics of the
atmospheric air. Generally, the lower the wet bulb temperature of
the atmospheric air, e.g., the humidity in the atmospheric air, the
more cooling that takes place within cooling tower 108. For
example, installation of cooling configuration 100 in geographic
locations known to have atmospheric air with low wet bulb
temperatures, such as deserts or arid climates, allows for
increased cooling or more efficient cooling in cooling tower 108
than an installation of cooling configuration 100 in a geographic
area with higher wet bulb temperatures. In arid climates, cooling
tower 108 may cool cooling water 124 to within three to five
degrees Fahrenheit of the wet bulb temperature. Thus, the exact
efficiencies of cooling tower 108 will vary with atmospheric
characteristics.
[0042] After the atmospheric air is cooled within cooling tower
108, the atmospheric air may be exhausted to the atmosphere through
atmospheric air exhaust 132 included in cooling tower 108. In some
embodiments, atmospheric air exhaust 132 may be located in cooling
tower 108 opposite from atmospheric air inlet 130 to form a defined
flow path of atmospheric air through cooling tower 108. In
alternate embodiments, the location of atmospheric air exhaust 132
may vary. Just as the atmospheric air exhausts from cooling tower
108, cooling water 124 that has been cooled, may also exit cooling
tower 108 at cooling tower outlet 158.
[0043] In some embodiments, cooling tower 108 may be fluidically
connected or coupled via piping to tower pumps 110. After the
cooling water 124 is cooled in cooling tower 108, cooling water 124
accumulates within cooling tower 108 and tower pumps 110 pumps
cooling water 124 through tower pumps 110. Tower pumps 110 may
include one or more pumps in various configurations. For example,
tower pumps 110 may be configured in parallel or may be configured
such that one pump may be designated as an operating tower pump
while additional pumps may be designated as a standby pump. Thus,
the operating pump normally pumps cooling water 124, while the
standby pump remains in standby in case the operating pump fails or
another system condition requires the use of the standby pump. In
alternate embodiments, tower pumps 110 may be configured in series
or a single pump may be utilized.
[0044] Tower pumps 110 may be variable speed, thus allowing
variable flow and/or pressure, or fixed speed pumps. Tower pumps
110 may be configured to maintain a consistent flow such as gallons
per minute (GPM). Further, tower pumps 110 may be particular
horsepower (hp) pumps. For example, tower pumps 110 may include one
pump configured to operate at fifty hp and generate a flow of 1,300
GPM. Tower pumps 110 may additionally include temperature sensors,
flow rate meters, pressure sensors, and/or any other suitable
components to allow for monitoring and control of tower pumps
110.
[0045] Tower pumps 110 may be used to circulate cooling water 124
through various components and subsystems of cooling system 180.
Tower pumps 110 may be fluidically connected or coupled via piping
to filtration subsystem 112. In some embodiments, tower pumps 110
may additionally be connected via piping to a chemical treatment
and monitoring subsystem. In such a configuration, piping connects
the chemical treatment and monitoring subsystem to filtration
subsystem 112 such that at least a portion of cooling water 124
circulates through the chemical treatment and monitoring subsystem
prior to entering filtration subsystem 112. The portion of cooling
water that enters the chemical treatment and monitoring subsystem
may be controlled by one or more valves. The valves may be
electronically controlled and coupled with other devices, such as
flow rate meters, to direct substantially exact portions of the
cooling water 124 to the chemical treatment and monitoring
subsystem in order to maintain consistent chemical properties in
the cooling water 124. The chemical treatment and monitoring
subsystem may chemically treat cooling water 124 to maintain an
optimum water chemistry. Additionally, a dedicated chemical
subsystem pump or alternate pressure source may circulate the
portion of cooling water 124 that enters the chemical treatment and
monitoring subsystem.
[0046] Tower pumps 110 may circulate cooling water 124 to enter
filtration subsystem 112 either directly or once cooling water 124
or a portion of cooling water 124 may be processed through the
chemical treatment and monitoring subsystem. Filtration subsystem
112 filters cooling water 124 before it enters tower valve 114a.
Filtration subsystem 112 may include, by way of example only, media
filters, screen filters, disk filters, slow sand filter beds, rapid
sand filters and cloth filters configured to filter various sizes
of particles from cooling water 124. In some embodiments,
filtration subsystem 112 will substantially prevent a particle of a
predetermined size or larger from circulating with cooling water
124 through the portion of cooling system 180 following filtration
subsystem 112. Filtration subsystem 112 may additionally include
temperature sensors, flow rate meters, pressure sensors, and/or any
other suitable components to allow for monitoring and control of
filtration subsystem 112.
[0047] Once cooling water 124 passes through filtration subsystem
112, cooling water 124 may enter one or more tower valves 114.
Depending on the configuration of tower valves 114, cooling water
124 will be directed to chiller subsystem 116 or to data center
118. Tower valves 114 configuration, and thus direction of cooling
water 124, will be based on the cooling system selected: free
cooling system 102, hybrid cooling system 104, or double loop
cooling system 106. Tower valves 114 may include one or more
two-way or three-way valves 164a and 164b to direct the flow of
cooling water 124. Tower valves 114 may be electronically
controlled and coupled with other devices, such as flow rate
meters, to direct cooling water 124. Tower valves 114 may
additionally include temperature sensors, flow rate meters,
pressure sensors, and/or any other suitable components to allow for
monitoring and control of tower valves 114.
[0048] In some embodiments, chiller subsystem or chiller 116 may be
utilized to further chill cooling water 124 in both hybrid cooling
system 104 and double loop cooling system 106. Chiller 116 may
include evaporator 136 and condenser 138. Condenser 138 may be
configured to absorb heat from either cooling water 124 or
secondary fluid 146 flowing through evaporator 136. Condenser 138
may include motors, fans, compressors, and/or any other suitable
machinery operable for absorbing heat and continuously providing
cooling to fluid traversing evaporator 136. Condenser 138 may
additionally include temperature sensors, flow rate meters,
pressure sensors, and/or any other suitable components to allow for
monitoring and control of condenser 138.
[0049] Evaporator 136 may be configured to work in connection with
condenser 138. Evaporator 136 may condition cooling water 124 or
secondary fluid 146 to a predetermined temperature, such as
approximately fifty-five degrees Fahrenheit. Cooling water 124 or
secondary fluid 146 may enter evaporator 136 at evaporator inlet
150. Cooling water 124, as part of hybrid cooling system 104,
enters evaporator from filtration subsystem 112 and tower valves
114. Cooling water 124 may be at a warm temperature, such as
approximately sixty-five degrees Fahrenheit. As another example,
secondary fluid 146 as part of secondary loop 106b in double loop
cooling system 106 may enter evaporator from load center 118 at a
warm temperature of approximately sixty-five degrees Fahrenheit.
Evaporator 136 may additionally include temperature sensors, flow
rate meters, pressure sensors, and/or any other suitable components
to allow for monitoring and control of evaporator 136.
[0050] Load center 118 may include any equipment and/or machinery
that generates heat during operation. For example, load center 118
may include computing data center that may contain multiple
computing systems, an industrial or manufacturing center, a
hospital, a school, a residence or residential facility, and/or any
other systems, buildings, or facilities that generate heat during
operation. Load center 118 may be designed to maintain a particular
environment for the protection of equipment and/or machinery
included in load center 118 and/or for the comfort of personnel in
load center 118. For example, load center 118 may be a data center
that may be designed to maintain a temperature of approximately
fifty-five degrees Fahrenheit and a humidity level below a certain
threshold, such as approximately fifty percent. Load center 118 may
additionally include temperature sensors, flow rate meters,
pressure sensors, and/or any other suitable components to allow for
monitoring and control of load center 118.
[0051] In some embodiments, load center 118 may include multiple
air-handler units 140, and/or humidification elements 142.
Generally, air-handler units 140 may provide an interface between
cooling water 124 cooled by cooling tower 108 and/or chiller 116
and load air 144 that may have been heated in load center 118. For
example, load air 144 may be heated by the operation of computing
centers in a data center. Load air 144 may be moved into
air-handler units 140 through ducting. Cooling water 134 may enter
load center 118 via piping, e.g., a cooling coil, that directs
cooling water 134 proximate to the air-handler units and/or the
heated data center air. As cooling water 134 passes proximate to
the air-handling units and/or the heated data center air, the
air-handling units may cause the heat in the data center air to
transfer to cooling water 134. For example, air-handling units in
the form of fans may blow the data center air across the piping
that contains cooling water 134. Thus, cooling water 134 that exits
data center 118 may be at a higher temperature than cooling water
134 that enters data center 118. The data center air that has been
cooled may be directed by the air-handling units back through data
center 118. Cooling water 134, which has been heated, may be
directed via piping to center valves 120.
[0052] The humidity of the data center air may be controlled by
humidification element 142. For example, if the humidity level
needs to be increased to maintain the correct environment,
humidification element 142 may inject water into ducting as load
air 144 enters air-handler units 140. In alternate embodiments, the
humidity of the data center air could be controlled through use of
an evaporative media section, or directly in load center 118.
[0053] In some embodiments, cooling water 124 may exit load center
118 and enter one or more center valves 120. Depending on the
configuration of center valves 120, cooling water 124 may be
directed to chiller 116, system pumps 122, or cooling tower 108.
Center valves 120 configuration, and thus direction of cooling
water 124, will be based on the cooling system selected: free
cooling system 102, hybrid cooling system 104, or double loop
cooling system 106. Center valves 120 may include one or more
two-way or three-way valves 166a and 166b to direct the flow of
cooling water 124. Center valves 120 may additionally include
temperature sensors, flow rate meters, pressure sensors, and/or any
other suitable components to allow for monitoring and control of
center valves 120.
[0054] In some embodiments, double loop cooling system 106 may
require utilizing one or more system pumps 122. System pumps 122
may include one or more pumps in various configurations. For
example, system pumps 122 may be configured in parallel or may be
configured such that one pump may be designated as an operating
system pump while an additional pump may be designated as a standby
pump. Thus, the operating pump normally pumps cooling water 124,
while the standby pump remains in standby in case the operating
pump fails or another system condition requires the use of the
standby pump. In alternate embodiments, system pumps 122 may be
configured in series or a single pump may be utilized. System pumps
122 may also require a freeze protection subsystem to prevent
damage if the pumps are exposed to temperatures below approximately
thirty-two degrees Fahrenheit. System pumps 122 may additionally
include temperature sensors, flow rate meters, pressure sensors,
and/or any other suitable components to allow for monitoring and
control of system pumps 122. System pumps 122 may be variable
speed, thus allowing variable flow and/or pressure, or fixed speed
pumps.
[0055] In some embodiments, cooling configuration 100 may be
implemented in environments that may be likely to experience
extremes in both temperature and humidity. For example, areas in
the United States such as Atlanta, Ga. or Houston, Tex. may
experience both high humidity and high temperatures for a certain
number of hours each year. The most efficient cooling system in
such areas may be a cooling system configured similar to cooling
configuration 100, e.g., including free cooling system 102, hybrid
cooling system 104, and double loop cooling system 106. However, in
drier climates that have a lower average wet bulb temperature, such
as Denver, Colo., a cooling configuration that may not include
double loop cooling system 106 may be more efficient.
[0056] FIG. 2 illustrates an example block diagram of exemplary
cooling configuration 200 that includes free cooling system 102 and
hybrid cooling system 104, in accordance with certain embodiments
of the present disclosure. Cooling configuration 200 may be similar
to cooling configuration 100 shown in FIG. 1. However, cooling
configuration 200 includes cooling system 280 that further includes
free cooling system 102 and hybrid cooling system 104. Cooling
system 280 may eliminate system pumps, such as system pump 122,
that might have been required in cooling system 180 of FIG. 1.
[0057] Cooling system 280 may include cooling tower 108, one or
more tower pumps 110, filtration subsystem 112, one or more tower
valves 114, chiller 116, load center 118, and/or one or more center
valves 120. Components of cooling system 280 may be fluidically
coupled. Cooling system 280 may include piping sections through
which a fluid circulates and that may connect components making up
free cooling system 102 and/or hybrid cooling system 104. Although
shown as two separate flows, fluid flowing through free cooling
system 102 and/or hybrid cooling system 104 may be contained in the
same pipe and/or piping structure.
[0058] In some embodiments, free cooling system 102 may include
cooling water 124 that circulates through a single loop of piping,
machinery, and/or other connections. Free cooling system 102 may
circulate cooling water 124 through cooling tower 108, tower pumps
110, filtration subsystem 112, tower valves 114, load center 118,
and/or center valves 120. Free cooling system 102 may further
include a chemical treatment and monitoring subsystem, a
temperature control subsystem, and/or a mechanical cooling
subsystem. Free cooling system 102 may be open to the exterior
environment at cooling tower 108.
[0059] Cooling water 124 circulating in free cooling system 102
exits cooling tower 108 through cooling tower outlet 158 in
temperature range TR.sub.A. Cooling water 124 that exits cooling
tower 108 may be at temperature T.sub.CT. For example, cooling
water 124 in free cooling system 102 may exit cooling tower 108 at
approximately T.sub.CT equal to approximately fifty-five degrees
Fahrenheit. Cooling water 124 circulates through tower pump 110,
filtration subsystem 112, and tower valves 114 to load center inlet
168 at approximately the same temperature, e.g. T.sub.CT. Cooling
water 124 is heated a defined number of degrees, e.g.
.DELTA.T.sub.L, while circulating through load center 118. For
example, cooling water 124 may be heated a .DELTA.T.sub.L equal to
approximately ten degrees Fahrenheit as a result of the desired
removal of heat from load center 118. Thus, in the current example,
cooling water 124 exiting load center 118 at load center outlet 162
may be in temperature range TR.sub.B or temperature equal to
approximately sixty-five degrees Fahrenheit. Cooling water 124
circulates though center valves 120 and back to cooling tower 108
to enter cooling tower inlet 160 in temperature range TR.sub.B or
temperature approximately sixty-five degrees Fahrenheit in the
current example. Cooling water 124 circulating in free cooling
system 102 circulates through cooling tower 108 and the temperature
of cooling water 124 may be lowered by .DELTA.T.sub.L. For example,
cooling water 124 exiting cooling tower 108, e.g. T.sub.CT, may
again be in temperature range TR.sub.A or approximately fifty-five
degrees Fahrenheit.
[0060] In some embodiments, cooling system 280 may also include
hybrid cooling system 104. Hybrid cooling system 104 includes
cooling water 124 that circulates through a single loop of piping,
machinery, and/or other connections. In operation, hybrid cooling
system 104 may circulate cooling water 124 through cooling tower
108, tower pumps 110, filtration subsystem 112, tower valves 114,
evaporator 136, load center 118, center valves 120, and condenser
138.
[0061] Cooling water 124 circulating in hybrid cooling system 104
exits cooling tower 108 through cooling tower outlet 158 in
temperature range TR.sub.B. Cooling water 124 that exits cooling
tower 108 may be at temperature T.sub.CT. For example, cooling
water 124 in hybrid cooling system 104 may exit cooling tower 108
at T.sub.CT equal to approximately sixty degrees Fahrenheit.
Cooling water 124 circulates through tower pump 110, filtration
subsystem 112, and tower valves 114 to evaporator 136 at evaporator
inlet 150 at approximately the same temperature, e.g. T.sub.CT. As
cooling water 124 circulates through evaporator 136, cooling water
124 is cooled a defined number of degrees, e.g. .DELTA.T.sub.C. For
example, cooling water 124 may be cooled a .DELTA.T equal to
approximately five degrees Fahrenheit to a temperature of
approximately fifty-five degrees Fahrenheit in temperature range
TR.sub.A. Cooling water 124 exits evaporator 136 at evaporator
outlet 152 and circulates to load center 118 while maintaining
approximately the same temperature. Cooling water 124 is heated
.DELTA.T.sub.L as it circulates in load center 118. .DELTA.T.sub.L
may be equal to approximately ten degrees Fahrenheit. Thus, in the
current example, cooling water 124 exiting load center 118 at load
center outlet 162 may be in temperature range TR.sub.B or
temperature equal to approximately sixty-five degrees Fahrenheit.
Cooling water 124 circulates though center valves 120 and to
condenser 138 to enter condenser inlet 154. Cooling water 124 is
heated .DELTA.T.sub.C while circulating through condenser 138. For
example, cooling water 124 may be heated a .DELTA.T.sub.C equal to
approximately five degrees Fahrenheit. Thus, in the current
example, cooling water 124 exiting condenser 138 at condenser
outlet 156 may be in temperature range TR.sub.C or temperature
equal to approximately seventy degrees Fahrenheit. Cooling water
124 circulates back to cooling tower 108. Cooling water 124 may
enter cooling tower inlet 160 in temperature range TR, or
temperature approximately seventy degrees Fahrenheit in the current
example. Cooling water 124 circulating in hybrid cooling system 104
circulates through cooling tower 108 and the temperature of cooling
water 124 is thus lowered by .DELTA.T.sub.L. For example, cooling
water 124 exiting cooling tower 108, e.g. T.sub.CT, may again be in
temperature range TR.sub.B or approximately sixty degrees
Fahrenheit.
[0062] FIG. 3 illustrates an example psychometric chart 300 showing
an exemplary cooling process utilizing a hybrid cooling system, in
accordance with certain embodiments of the present disclosure. The
psychometric chart illustrates psychometric properties of the
exterior air prior to entering cooling systems 180 or 280 shown
with reference to FIGS. 1 and 2. Psychometric chart 300 may be
based on a system designed to deliver approximately fifty-five
degree Fahrenheit cooling water 124 to load center 118, e.g.,
cooling water 124 supply temperature. Psychometric chart 300 may
further be based on a heat load at load center 118 of approximately
ten degrees Fahrenheit, e.g., cooling water 124 may heat from
approximately fifty-five degrees Fahrenheit entering load center
118 to approximately sixty-five degrees Fahrenheit leaving load
center 118. Additionally, psychometric chart 300 may be based on
cooling tower 108 approach temperature. For example, cooling tower
108 may be a five degree Fahrenheit approach cooling tower.
However, modifications may be made to psychometric chart 300, e.g.,
locations of free cooling line 308 and hybrid cooling line 310,
based on a different designed cooling water 124 supply temperature,
a different heat load at load center 118, and/or a different
cooling tower 108 approach temperature. It is notable that the
largest efficiencies and thus, greatest cost savings, may be
accomplished with smaller cooling tower 108 approach temperatures,
higher cooling water 124 supply temperatures, and/or larger
temperature gains from the load.
[0063] In some embodiments, psychometric zone 302 may correspond to
exterior air properties that enable free cooling system 102 to be
the most efficient operating mode for cooling systems 180 and 280.
For example, free cooling line 308 corresponds to wet bulb
temperature of approximately fifty degrees Fahrenheit. Exterior air
with properties at or below free cooling line 308, e.g., below or
equal to wet bulb temperature of approximately fifty degrees
Fahrenheit, may indicate that free cooling system 102 may be the
most efficient Free cooling line 308 may be based on the amount of
cooling that may be generated by cooling tower 108. Thus, in the
present example, if free cooling line 308 is set at a wet bulb
temperature of approximately five degrees Fahrenheit below the
designed cooling water 124 temperature, then cooling tower 108 is
able to lower the temperature of cooling water 124 entering cooling
tower inlet 160 from approximately sixty-five degrees Fahrenheit to
approximately fifty-five degrees Fahrenheit. Therefore, at wet bulb
temperatures below approximately fifty degrees Fahrenheit, cooling
system 180 or 280 may not require the use of chiller 116 and energy
savings may be accomplished with free cooling system 102.
[0064] In some embodiments, psychometric zone 304 may correspond to
exterior air properties that enable hybrid cooling system 104 to be
the most efficient operating mode for cooling systems 180 and 280.
For example, hybrid cooling line 310 corresponds to wet bulb
temperature of approximately sixty degrees Fahrenheit. Thus, at
free cooling line 308, cooling system 180 or 280 may transition
from free cooling system 102 to hybrid cooling system 104. Tower
valves 114 are configured such that cooling water 124 is directed
from filtration subsystem 112 to evaporator 136. Center valves 120
are configured such that cooling water 124 is directed from load
center 118 to condenser 138.
[0065] Exterior air with properties at or below hybrid cooling line
310 and above free cooling line 308, e.g., at wet bulb temperatures
between approximately fifty degrees Fahrenheit and sixty degrees
Fahrenheit, may indicate that hybrid cooling system 104 may be the
most efficient. Hybrid cooling system 104 may maximize the
available free cooling, e.g., operation of cooling tower 108, and
minimize the energy use of chiller 116 by using part load
conditions that may deliver better efficiency. For example, hybrid
cooling system 104 may be most efficient when cooling tower 108 can
produce between approximately fifty-five degrees Fahrenheit and
approximately sixty-five degrees Fahrenheit cooling water 124
(assuming an approximately five degree Fahrenheit approach cooling
tower). This amount of cooling corresponds to wet bulb temperatures
between approximately fifty degrees Fahrenheit and sixty degrees
Fahrenheit.
[0066] Accordingly, in the current example system, the load carried
by chiller 116 may vary based on the exterior air wet bulb
temperature. For example, at a wet bulb temperature less than or
equal to approximately fifty degrees Fahrenheit, chiller 116 load
may be approximately zero percent (e.g., free cooling system 102).
At a wet bulb temperature of approximately fifty-one degrees
Fahrenheit, chiller 116 load may be approximately ten percent
(e.g., hybrid cooling system 104). The percentage load on chiller
116 may continue to increase as the wet bulb temperature increases
until at approximately sixty degrees Fahrenheit, chiller 116 load
may be approximately one hundred percent.
[0067] In some embodiments, psychometric zone 306 may correspond to
exterior air properties that enable double loop cooling system 106
operating mode for cooling system 180. Exterior air with properties
above hybrid cooling line 310, e.g., at wet bulb temperatures above
approximately sixty degrees Fahrenheit, may indicate that double
loop cooling system 106 as the option for cooling. For example,
above hybrid cooling line 310, chiller 116 load may be
approximately one hundred percent. Cooling system 180 may
transition to first loop 106a and second loop 106b that utilizes
secondary coolant 146.
[0068] Accordingly, energy efficiencies may occur through
utilization of hybrid cooling system 104 at the appropriate wet
bulb temperatures. As an example, Table 1 illustrates the
approximate percentage load carried by chiller 116 at particular
wet bulb temperatures that may be employed in operation of hybrid
cooling system 104.
TABLE-US-00001 TABLE 1 Wet Bulb Temperature Load on Chiller 116
Less than or equal to 50 degrees Fahrenheit 0% 51 degrees
Fahrenheit 10% 52 degrees Fahrenheit 20% 53 degrees Fahrenheit 30%
54 degrees Fahrenheit 40% 55 degrees Fahrenheit 50% 56 degrees
Fahrenheit 60% 57 degrees Fahrenheit 70% 58 degrees Fahrenheit 80%
59 degrees Fahrenheit 90% Greater than or equal to 60 degrees
Fahrenheit 100%
[0069] In determining design parameters for cooling system 180 of
FIG. 1 or 280 of FIG. 2, atmospheric data may be gathered for a
particular location where the cooling system may be placed. For
example, a wet bulb temperature profile may be gathered or
generated for a particular city. The wet bulb temperature profile
may include the average number of hours in a year at each wet bulb
temperature.
First Example
[0070] As a first example, a wet bulb temperature profile for
Denver, Colo., may indicate that on average Denver may not ever
experience a wet bulb temperature above approximately sixty-nine
degrees Fahrenheit. In such a location with low wet bulb
temperatures, a cooling system similar to cooling configuration 200
shown with reference to FIG. 2 may be utilized. For example, a
cooling system may have a load of approximately 800 tons, e.g.,
heat to be dissipated at load center 118. Cooling tower 108 may be
designed as a five degree Fahrenheit approach cooling tower. For
example, cooling tower 108 may be Marley cooling tower manufactured
by SPX Cooling Technologies, Inc. (Overland Park, Kans.). Tower
pump 110 may be a variable speed drive approximately fifty
horsepower pump with a flow rate that may range from approximately
600 GPM to 1,300 GPM. Chiller 116 may be a 2,450 kW chiller
manufactured by Trane, an Ingersoll Rand company (Davidson, N.C.).
Chiller 116 flow rate may range from approximately 0.75 GPM/ton to
1.6 GPM/ton. Cooling water 124 supply temperature may be
approximately fifty-five degrees Fahrenheit. The minimum chiller
116 lift may be approximately twelve degrees Fahrenheit.
[0071] During operation of the current example, a psychometric
chart, such as psychometric chart 300, for the designed system may
place free cooling line 308 at approximately fifty-one degrees. The
designed system may place hybrid cooling line 310 at approximately
sixty degrees Fahrenheit. For approximately seventy-one percent of
the hours in each year, the wet bulb temperature may be lower than
approximately fifty-one degrees Fahrenheit. Thus, cooling system
280 may be configured to operate free cooling system 102. Tower
valve 114 and center valve 120 may be positioned to bypass chiller
116 in operation of free cooling system 102.
[0072] For an additional approximately twenty-nine percent of the
hours in each year, the wet bulb temperature may be lower than
approximately sixty-five degrees Fahrenheit. Hybrid cooling system
104 may be the most efficient mode to operate at these wet bulb
temperatures. As such, the valves may be reconfigured to direct
cooling water 124 to chiller 116 and chiller 116 may be started.
For example, tower valve 114 may be positioned to direct flow to
evaporator 136 and center valve 120 may be positioned to direct
flow to condenser 138.
[0073] In the current example, the location may experience only
approximately eleven hours per year with a wet bulb temperature
over approximately sixty-five degrees Fahrenheit. For these few
hours, rather than installing a double loop cooling system, which
may require a separate pump and additional valves, hybrid cooling
system 104 may be extended to these temperatures by decreasing the
cooling water flow. For example, the pump flow rate may be
decreased from approximately 1,300 GPM to approximately 1,000
GPM.
[0074] Without implementation of free cooling system 102 and hybrid
cooling system 104, the chiller may run approximately 800 tons of
cooling year round (8,760 hours) using a standard double loop
configuration consuming approximately 3,611,047 kilowatt-hours of
energy. Using the combined free cooling system 102 and hybrid
cooling system 104 systems the resultant annual energy consumption
is approximately 701,808 kilowatt-hours of energy an approximately
eighty-one percent (81%) decrease in cooling consumption and
cost.
Second Example
[0075] As a second example, a wet bulb temperature profile for
Boston, Mass., may indicate that on average Boston may experience
wet bulb temperatures as high as approximately seventy-seven
degrees Fahrenheit. In such a location with relatively high wet
bulb temperatures, a cooling system similar to cooling
configuration 100 shown with reference to FIG. 1 may be utilized.
For example, a cooling system may have a load of approximately 800
tons, e.g., heat to be dissipated at load center 118. Cooling tower
108 may be designed as a five degree Fahrenheit approach cooling
tower. For example, cooling tower 108 may be Marley cooling tower
manufactured by SPX Cooling Technologies, Inc. (Overland Park,
Kans.). Tower pump 110 and system pump 122 may be variable speed
drive approximately fifty horsepower pumps with a flow rate that
may range from approximately 600 GPM to 1,000 GPM. Chiller 116 may
be a 2,450 kW chiller manufactured by Trane, an Ingersoll Rand
company (Davidson, N.C.). Chiller 116 flow rate may range from
approximately 0.75 GPM/ton to 1.3 GPM/ton. Cooling water 124 supply
temperature may be approximately fifty-five degrees Fahrenheit. The
minimum chiller 116 lift may be approximately twelve degrees
Fahrenheit.
[0076] During operation of the current example, a psychometric
chart, such as psychometric chart 300, for the designed system may
place free cooling line 308 at approximately fifty-one degrees. The
designed system may place hybrid cooling line 310 at approximately
sixty degrees Fahrenheit. For approximately sixty-one percent of
the hours in each year, the wet bulb temperature may be lower than
approximately fifty-one degrees Fahrenheit. Thus, cooling system
180 may be configured to operate free cooling system 102. Tower
valves 114 and center valves 120 may be positioned to bypass the
chiller in operation of free cooling system 102.
[0077] For an additional approximately twenty-nine percent of the
hours in each year, the wet bulb temperature may be lower than
approximately sixty-five degrees Fahrenheit. Hybrid cooling system
104 may be the most efficient mode to operate at these wet bulb
temperatures. As such, the valves may be reconfigured to direct
cooling water 124 to chiller 116 and chiller 116 may be started.
For example, tower valves 114 may be positioned to direct flow to
evaporator 136 and center valves 120 may be positioned to direct
flow to condenser 138.
[0078] In the current example, the location may experience
approximately ten percent of the hours in each year with a wet bulb
temperature over approximately sixty-five degrees Fahrenheit.
Double loop cooling system 106 may be the mode to operate at these
wet bulb temperatures. As such, first loop 106a may be configured
so that tower valves 114 may direct cooling water 124 to condenser
138. Second loop 106b may be configured so that center valves 120
direct secondary coolant 146 to evaporator 136. System pump 122 may
also be started in the transition to double loop cooling system
106.
[0079] In the current example, the wet-bulb temperature profile
includes hours in all three modes of cooling system 180 operation.
For example, there may be approximately 416 hours of double loop
cooling system 106 operation, 2,994 hours of hybrid cooling system
104 operation, and 5,350 hours of free cooling system 102
operation. A typical system may run approximately 800 tons of
cooling year round (8,760 hours) using double loop configuration
exclusively and consume approximately 3,611,047 kilowatt-hours of
energy. Using the combined free cooling system 102, hybrid cooling
system 104 and double loop cooling system 106, the resultant annual
energy consumption may be approximately 1,085,699 kilowatt-hours of
energy resulting in an approximately seventy percent (70%) decrease
in cooling consumption and cost.
Third Example
[0080] As a third example, a wet bulb temperature profile for
Dallas, Tex., may indicate that on average Dallas may experience
wet bulb temperatures as high as approximately eighty-three degrees
Fahrenheit. In such a location with relatively high wet bulb
temperatures, a cooling system similar to cooling configuration 100
shown with reference to FIG. 1 may be utilized. For example, a
cooling system may have a load of approximately 800 tons, e.g.,
heat to be dissipated at load center 118. Cooling tower 108 may be
designed as a five degree Fahrenheit approach cooling tower. For
example, cooling tower 108 may be Marley cooling tower manufactured
by SPX Cooling Technologies, Inc. (Overland Park, Kans.). Tower
pump 110 and system pump 122 may be variable speed drive
approximately fifty horsepower pumps with a flow rate that may
range from approximately 600 GPM to 1,000 GPM. Chiller 116 may be a
2,450 kW chiller manufactured by Trane, an Ingersoll Rand company
(Davidson, N.C.). Chiller 116 flow rate may range from
approximately 0.75 GPM/ton to 1.3 GPM/ton. Cooling water 124 supply
temperature may be approximately fifty-five degrees Fahrenheit. The
minimum chiller 116 lift may be approximately twelve degrees
Fahrenheit.
[0081] During operation of the current example, a psychometric
chart, such as psychometric chart 300, for the designed system may
place free cooling line 308 at approximately fifty-one degrees. The
designed system may place hybrid cooling line 310 at approximately
sixty degrees Fahrenheit. For approximately thirty-four percent of
the hours in each year, the wet bulb temperature may be lower than
approximately fifty-one degrees Fahrenheit. Thus, cooling system
180 may be configured to operate free cooling system 102. Tower
valves 114 and center valves 120 may be positioned to bypass the
chiller in operation of free cooling system 102.
[0082] For an additional approximately twenty-eight percent of the
hours in each year, the wet bulb temperature may be lower than
approximately sixty-five degrees Fahrenheit. Hybrid cooling system
104 may be the most efficient mode to operate at these wet bulb
temperatures. As such, the valves may be reconfigured to direct
cooling water 124 to chiller 116 and chiller 116 may be started.
For example, tower valves 114 may be positioned to direct flow to
evaporator 136 and center valves 120 may be positioned to direct
flow to condenser 138.
[0083] In the current example, the location may experience
approximately thirty-eight percent of the hours in each year with a
wet bulb temperature over approximately sixty-five degrees
Fahrenheit. Double loop cooling system 106 may be the mode to
operate at these wet bulb temperatures. As such, first loop 106a
may be configured so that tower valves 114 may direct cooling water
124 to condenser 138. Second loop 106b may be configured so that
center valves 120 direct secondary coolant 146 to evaporator 136.
System pump 122 may also be started in the transition to double
loop cooling system 106.
[0084] In the current example, the wet-bulb temperature profile
includes hours in all three modes of cooling system 180 operation.
For example, there may be approximately 2,589 hours of double loop
cooling system 106 operation, 3,155 hours of hybrid cooling system
104 operation, and 3,016 hours of free cooling system 102
operation. A typical system may run approximately 800 tons of
cooling year round (8,760 hours) using a standard double loop
configuration consuming approximately 3,611,047 kilowatt-hours of
energy. Using the combined free cooling system 102, hybrid cooling
system 104 and double loop cooling system 106, the resultant annual
energy consumption may be approximately 1,993,156 kilowatt-hours of
energy resulting in an approximately forty-five percent (45%)
decrease in cooling consumption and cost.
[0085] FIG. 4 illustrates a flow chart for an example method for
cooling system transitions using hybrid cooling systems, in
accordance with certain embodiments of the present disclosure. The
steps of method 600 may be performed by various computer programs,
models or any combination thereof. The programs and models may
include instructions stored on a computer-readable medium that are
operable to perform, when executed, one or more of the steps
described below. The computer-readable medium may include any
system, apparatus or device configured to store and/or retrieve
programs or instructions such as a microprocessor, a memory, a disk
controller, a compact disc, flash memory or any other suitable
device. The programs and models may be configured to direct a
processor or other suitable unit to retrieve and/or execute the
instructions from the computer-readable medium. For example, method
400 may be executed by processing system 126, an operator of the
cooling system, and/or other suitable source. For illustrative
purposes, method 400 may be described with respect to cooling
system 180 of FIG. 1; however, method 400 may be used for cooling
system transitions using hybrid cooling system of any suitable
configuration.
[0086] Although FIG. 4 discloses a particular number of steps to be
taken with respect to method 400, method 400 may be executed with
greater or lesser steps than those depicted in FIG. 4. In addition,
although FIG. 4 discloses a certain order of steps to be taken with
respect to method 400, the steps comprising method 400 may be
completed in any suitable order.
[0087] At step 405, method 400 determines the temperature of
cooling water that exits a cooling tower, e.g., T.sub.CT. For
example, with reference to FIG. 1, a temperature sensor senses the
temperature of cooling water 124 as cooling water 124 exits cooling
tower 108 at cooling tower outlet 158. Processing system 126
receives the sensed temperature or T.sub.CT.
[0088] At step 410, method 400 determines if the sensed temperature
of cooling water exiting the cooling tower is greater than a preset
temperature, T.sub.1. For example, processing system 126 determines
if T.sub.CT may be greater than T.sub.1. T.sub.1 is based on design
considerations, atmospheric conditions, sizes and loads on
components in the cooling system, and/or any other suitable factor.
T.sub.1 may be the temperature at which it becomes more efficient
to operate cooling system as a hybrid cooling system in place of a
free cooling system. For example, with reference to FIG. 1, T.sub.1
may be set at approximately fifty-five degrees Fahrenheit. In this
example, when the cooling water exiting temperature, T.sub.CT, is
less than or equal to approximately fifty-five degrees Fahrenheit,
then method 400 proceeds to step 415. If T.sub.CT is greater than
approximately fifty-five degrees Fahrenheit, method 400 proceeds to
step 425.
[0089] At step 415, method 400 is configured to operate a free
cooling system and configure the tower valves to direct the cooling
water to the load center. For example, with reference to FIG. 1,
processing system 126 electronically configures tower valve 164a to
direct cooling water 124 from filtration subsystem 112 to load
center 118.
[0090] At step 420, method 400 configures the center valves to
direct the cooling water to the cooling tower. For example,
processing system 126 electronically configures center valve 166a
to direct cooling water 124 from load center 118 to cooling tower
108. After step 420, method 400 returns to step 405.
[0091] At step 425, method 400 determines if the sensed temperature
of cooling water exiting the cooling tower is greater than a preset
temperature, T.sub.2. For example, processing system 126 determines
if T.sub.CT may be greater than T.sub.2. T.sub.2 may be based on
design considerations, atmospheric conditions, sizes and loads on
components in the cooling system, and/or any other suitable factor.
T.sub.2 may be the temperature at which it becomes necessary to
operate the cooling system as a double loop cooling system in place
of a hybrid cooling system. For example, with reference to FIG. 1,
T.sub.2 is set at approximately sixty-five degrees Fahrenheit. In
this example, when the cooling water exiting temperature, T.sub.CT,
is below or equal to approximately sixty-five degrees Fahrenheit,
then method 400 proceeds to step 430. If T.sub.CT is greater than
approximately sixty-five degrees Fahrenheit, method 400 proceeds to
step 440.
[0092] At step 430, method 400 is configured to operate a hybrid
cooling system and configures the tower valves to direct the
cooling water to the evaporator. For example, with reference to
FIG. 1, processing system 126 electronically configures tower valve
164a to direct cooling water 124 from filtration subsystem 112 to
tower valve 164b. Processing system 126 further electronically
configures tower valve 164b to direct cooling water 124 from tower
valve 164a to evaporator 136.
[0093] At step 435, method 400 configures the center valves to
direct the cooling water to the condenser. For example, processing
system 126 electronically configures center valve 166a to direct
cooling water 124 from load center 118 to center valve 166b.
Processing system 126 further electronically configures center
valve 166b to direct cooling water 124 from load center 118 to
condenser 138. After step 435, method 400 returns to step 405.
[0094] At step 440, method 400 is configured to operate a double
loop cooling system and configures the tower valves to direct the
cooling water to the condenser. For example, with reference to FIG.
1, processing system 126 electronically configures tower valve 164a
to direct cooling water 124 from filtration subsystem 112 to tower
valve 164b. Processing system 126 further electronically configures
tower valve 164b to direct cooling water 124 from tower valve 164a
to condenser 138.
[0095] At step 445, method 400 configures the center valves to
direct a secondary coolant to the evaporator. For example,
processing system 126 electronically configures center valve 166a
to direct secondary fluid 146 from load center 118 to center valve
166b. Processing system 126 further electronically configures
center valve 166b to direct coolant 146 from center valve 166a to
evaporator 136. After step 445, method 400 returns to step 405.
[0096] Modifications, additions, or omissions may be made to method
400 without departing from the scope of the present disclosure and
invention. For example, the order of the steps may be performed in
a different manner than that described and some steps may be
performed at the same time. For example, step 425 and step 410 may
be performed simultaneously. Additionally, each individual step may
include additional steps without departing from the scope of the
present disclosure. For example, step 415 may be preformed before
or after step 410 without departing from the scope of the present
disclosure.
[0097] Although the present invention and its advantages have been
described in detail, it should be understood that various changes,
substitutions and alternations can be made herein without departing
from the spirit and scope of the invention which is solely defined
by the following claims.
* * * * *