U.S. patent application number 14/576049 was filed with the patent office on 2016-06-23 for method and system for pre-cooling.
The applicant listed for this patent is CLEAResult Consulting, Inc.. Invention is credited to William A. Gast, JR., David Rocha.
Application Number | 20160178262 14/576049 |
Document ID | / |
Family ID | 56128997 |
Filed Date | 2016-06-23 |
United States Patent
Application |
20160178262 |
Kind Code |
A1 |
Rocha; David ; et
al. |
June 23, 2016 |
METHOD AND SYSTEM FOR PRE-COOLING
Abstract
Methods and systems are provided for pre-cooling. The cooling
system includes a condenser including a condenser inlet and a
condenser outlet. The system also includes a cooling tower
including a cooling tower inlet and a cooling tower outlet. The
system further includes a heat exchanger including a first heat
exchanger inlet and a first heat exchanger outlet. The first heat
exchanger inlet is fluidically coupled to the cooling tower outlet,
and the first heat exchanger outlet is fluidically coupled to the
condenser inlet.
Inventors: |
Rocha; David; (Austin,
TX) ; Gast, JR.; William A.; (Buda, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CLEAResult Consulting, Inc. |
Austin |
TX |
US |
|
|
Family ID: |
56128997 |
Appl. No.: |
14/576049 |
Filed: |
December 18, 2014 |
Current U.S.
Class: |
62/98 ; 62/115;
62/180; 62/513 |
Current CPC
Class: |
F25B 25/005 20130101;
F25B 2339/047 20130101; F25B 49/027 20130101 |
International
Class: |
F25B 49/02 20060101
F25B049/02 |
Claims
1. A cooling system comprising: a condenser including a condenser
inlet and a condenser outlet; a cooling tower including a cooling
tower inlet and a cooling tower outlet; and a heat exchanger
including a first heat exchanger inlet and a first heat exchanger
outlet, the first heat exchanger inlet fluidically coupled to the
cooling tower outlet, and the first heat exchanger outlet
fluidically coupled to the condenser inlet.
2. A system according to claim 1, further comprising: a load center
including a load center inlet and a load center outlet; an
evaporator including an evaporator inlet and an evaporator outlet;
and wherein the heat exchanger includes a second heat exchanger
inlet and a second heat exchanger outlet, the second heat exchanger
inlet fluidically coupled to the load center outlet, and the second
heat exchanger outlet fluidically coupled to the evaporator
inlet.
3. A system according to claim 1, further comprising a temperature
sensor to obtain a temperature of a first fluid that exits the
cooling tower outlet.
4. A system according to claim 3, wherein the cooling tower
includes a variable speed fan configured to adjust fan speed based
on the obtained temperature.
5. A system according to claim 3, further comprising, based on the
obtained temperature being greater than a first preset temperature,
a piping structure configured to direct the first fluid from the
cooling tower outlet to the heat exchanger inlet, from the heat
exchanger outlet to the condenser inlet, and from the condenser
outlet to the cooling tower inlet.
6. A system according to claim 2, further comprising: a temperature
sensor to obtain a temperature of a first fluid that exits the
cooling tower outlet; and based on the obtained temperature being
greater than a first preset temperature, a piping structure
configured to direct a second fluid from the evaporator outlet to
the load center inlet and from the load center outlet to the second
heat exchanger inlet.
7. A system according to claim 6, further comprising based on the
obtained temperature being less than or equal to a first preset
temperature, a chiller configured to be non-operational, the
chiller including the condenser and evaporator.
8. A system according to claim 2, further comprising: a temperature
sensor to obtain a temperature of a wet bulb temperature of an
exterior atmosphere; and based on the obtained temperature being
greater than a first preset temperature, a piping structure
configured to direct a second fluid from the evaporator outlet to
the load center inlet and from the load center outlet to the second
heat exchanger inlet.
9. A system according to claim 8, further comprising based on the
obtained temperature being less than or equal to a first preset
temperature, a chiller configured to be non-operational, the
chiller including the condenser and evaporator.
10. 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.
11. A system according to claim 2, further comprising a first
variable speed pump configured to circulate a first fluid and
maintain a flow rate of the first fluid.
12. A system according to claim 11, wherein the first fluid is
cooling water.
13. A system according to claim 11, further comprising a second
variable speed pump configured to circulate a second fluid and
maintain a flow rate of the second fluid.
14. A system according to claim 13, wherein the second fluid is
coolant.
15. A method for a cooling system comprising: obtaining a cooling
tower exit temperature of a first fluid; based on the obtained
temperature being greater than a first preset temperature, the
first fluid directed from a cooling tower outlet to a first heat
exchanger inlet, from a first heat exchanger outlet to a condenser
inlet, and from a condenser outlet to a cooling tower inlet.
16. A method according to claim 15, further comprising based on the
obtained temperature being greater than the first preset
temperature, a second fluid directed from an evaporator outlet to a
load center inlet and from a load center outlet to a second heat
exchanger inlet.
17. A method according to claim 15, further comprising based on the
obtained temperature being less than or equal to the first preset
temperature, configure a chiller to be non-operational, the chiller
including an evaporator and a condenser.
18. A method according to claim 16, further comprising configuring
a variable speed pump to circulate the first fluid and maintain a
flow rate of the first fluid.
19. A method according to claim 16, further comprising configuring
a variable speed pump to circulate the second fluid and maintain a
flow rate of the second fluid.
20. A method according to claim 16, further comprising configuring
a variable speed fan in the cooling tower to adjust fan speed based
on the temperature of the first fluid that exits the cooling tower
outlet.
Description
TECHNICAL FIELD
[0001] The present disclosure relates in general to cooling systems
for buildings and process load centers, and more particularly to
pre-cooling systems and associated methods.
BACKGROUND
[0002] 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 within 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
is encouraging driving data centers, especially large data centers,
to find and use more energy efficient methods and systems.
[0003] 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. Additionally,
cooling systems 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.
SUMMARY
[0004] In accordance with one embodiment of the present disclosure,
a cooling system is provided that includes a condenser including a
condenser inlet and a condenser outlet. The system also includes a
cooling tower including a cooling tower inlet and a cooling tower
outlet. The system further includes a heat exchanger including a
first heat exchanger inlet and a first heat exchanger outlet. The
first heat exchanger inlet is fluidically coupled to the cooling
tower outlet, and the first heat exchanger outlet is fluidically
coupled to the condenser inlet.
[0005] In accordance with another embodiment of the present
disclosure, a method for a cooling system is disclosed. The method
includes obtaining a cooling tower exit temperature of a first
fluid. Based on the obtained temperature being greater than a first
preset temperature, the first fluid is directed from a cooling
tower outlet to a first heat exchanger inlet, from a first heat
exchanger outlet to a condenser inlet, and from a condenser outlet
to a cooling tower inlet.
[0006] 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
[0007] 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:
[0008] FIG. 1 illustrates an example block diagram of an exemplary
cooling configuration for multiple cooling modes in accordance with
certain embodiments of the present disclosure;
[0009] FIG. 2 illustrates an example psychometric chart showing an
exemplary cooling process utilizing a multiple mode cooling system
in accordance with certain embodiments of the present disclosure;
and
[0010] FIG. 3 illustrates a flow chart for an example method for
cooling system transitions using multiple cooling modes in
accordance with certain embodiments of the present disclosure.
DETAILED DESCRIPTION
[0011] Design and specifications relating to a cooling system for a
building that houses equipment or personnel may be based on a
target environment, which may include a designed or target
temperature and a designed or target humidity. Based on the target
environment and the amount of heat generated in a building or
portion of a building, the cooling system provides a particular
incoming temperature of chilled water, coolant, or fluid. As an
example, a large data center may create an approximately 625 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. For
example, based on the target environment for the building, the
specified incoming fluid temperature may be approximately
fifty-five degrees Fahrenheit. The fluid exiting the building is at
a higher temperature based on the load in the building. For
example, the fluid exiting the building may be at approximately
seventy degrees Fahrenheit.
[0012] A cooling system may include a chiller to cool the fluid
exiting the building. The chiller, when in operation, consumes a
large amount of energy. Thus, improvements to the efficiency of
cooling systems may be based on minimizing the requirements placed
on the chiller. In the present disclosure, systems and methods are
presented to provide pre-cooling of the fluid before it enters the
chiller. Such pre-cooling reduces the amount of cooling that needs
to take place in the chiller. In some embodiments, the cooling
system may be configured to transition between multiple cooling
modes. The transition may be based on the wet bulb temperature,
target air temperatures for a building or portion of a building, or
the fluid temperature exiting a cooling tower. As such, the cooling
mode selected is appropriate or more efficient under the particular
atmospheric and systemic conditions. The cooling system provides
seamless transitions between economizing (for example, maximum
utilization of free cooling through a cooling tower) and mechanical
cooling (for example, operating a chiller to provide cooling).
[0013] Preferred embodiments and their advantages are best
understood by reference to FIGS. 1 through 3, wherein like numbers
are used to indicate like and corresponding parts.
[0014] FIG. 1 illustrates an example block diagram of an exemplary
cooling configuration 100 for multiple cooling modes 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 data center may create an approximately 625 ton load and require
a target ambient air temperature of approximately sixty-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 "cooling system" with chilled coolant. For
example, based on the target environment for load center 118, the
specified incoming coolant temperature may be between approximately
fifty-five and sixty degrees Fahrenheit. As another example, load
center 118 may be a hospital with a specified incoming coolant
temperature of approximately forty-five degrees Fahrenheit.
[0015] Cooling configuration 100 may include cooling system 180 and
processing system 126. Cooling system 180 may be configured as a
double loop cooling system. In a double loop cooling system,
cooling fluid flowing in first loop 104 is maintained separately
from cooling fluid flowing in second loop 106. Cooling system 180
may include one or more cooling towers 108, one or more tower pumps
110, one or more filters 112, heat exchanger 114, chiller 116, load
center 118, and/or one or more system pumps 122. Components of
cooling system 180 may be fluidically coupled. Cooling system 180
may include piping sections through which a fluid circulates and
that may connect components making up first loop 104. Also, cooling
system 180 may include piping sections through which a fluid
circulates and that may connect components making up second loop
106. The inclusion of first loop 104 and second loop 106 may allow
the use of two different coolants or fluids that may be circulated
separately. Fluid flowing through cooling system 180 may be
contained in the same pipe, multiple pipes, or piping structure and
may confine the same fluid in a continuous flow.
[0016] Additionally, fluids 124a and 124b (collectively "fluids
124"), for example, coolant, cooling water, or other cooling fluid,
circulate through cooling system 180 at various temperatures at
different sections of cooling system 180. Temperature measurement
may be accomplished by temperature sensors placed and configured to
measure fluids 124 or exterior temperatures or wet bulb
temperatures as suitable for a specific implementation. Cooling
system 180 includes fluid 124a that circulates through first loop
104 of piping, machinery, and other connections, and fluid 124b
that circulates through second loop 106 of separate piping,
machinery, and other connections.
[0017] In some embodiments, cooling system 180 may operate in
different modes of cooling. For example, cooling system 180 may
operate in a free-cooling mode, a pre-cooling mode, and a
mechanical-cooling mode. In the present disclosure, the example
temperature differences, loads, and efficiencies discussed below
with respect to load center 118, heat exchanger 114, chiller 116,
and cooling towers 108 are for ease of example and a cooling system
design may account for larger or smaller temperature differences
and different inlet and outlet temperatures as suitable for a
particular implementation.
[0018] In some embodiments, cooling system 180 may operate in
free-cooling mode when the atmospheric temperature is below a
target wet bulb temperature T.sub.1. For example, at a target wet
bulb temperature less than or equal to approximately forty-nine
degrees Fahrenheit (T.sub.1), free-cooling mode may be the most
efficient cooling mode to operate. Additionally, operation in
free-cooling mode may be based on the temperature of fluid 124a
exiting cooling tower 108 at cooling tower outlet 158, T.sub.CT. In
some embodiments, if T.sub.CT is less than the target temperature
of fluid 124b at load center inlet 160, free-cooling mode may be
the most efficient cooling mode to operate. For example, T.sub.CT
may be approximately fifty-three degrees Fahrenheit and the target
temperature of fluid 124b at load center inlet 160 may be
approximately fifty-five degrees Fahrenheit.
[0019] In free-cooling mode, chiller 116 is inactive and all
cooling is accomplished by cooling towers 108. However, as the wet
bulb temperature rises above T.sub.1, free-cooling mode may not be
the proper cooling mode to operate because the required cooling may
not be provided by operation of cooling towers 108 alone. Thus,
cooling system 180 may be configured to transition from
free-cooling mode to another cooling mode when the atmospheric
conditions or other suitable parameters indicate that free-cooling
mode is no longer able to provide sufficient cooling. For exemplary
purposes, the following discussion of free-cooling mode assumes a
wet bulb temperature, T.sub.WB, of approximately forty-nine degrees
Fahrenheit.
[0020] Free-cooling mode circulates fluid 124a in first loop 104
through tower pumps 110, filters 112, heat exchanger 114, and
condenser 138. Free-cooling mode circulates fluid 124b in second
loop 106 through evaporator 136, load center 118, system pumps 122,
and heat exchanger 114. Fluids 124 may be passed thorough chiller
116 or chiller bypass valves may be utilized to divert fluids 124
around chiller 116. Thus, in free-cooling mode, chiller 116 may be
inactive or switched off and cooling towers 108 may provide
approximately one hundred percent of cooling for load center
118.
[0021] Fluid 124b circulating in free-cooling mode exits evaporator
136 through evaporator outlet 152 or bypasses evaporator 136 at a
temperature of approximately fifty-five degrees Fahrenheit for
example. Fluid 124b circulates through load center 118 and absorbs
heat of a desired number of degrees. For example, fluid 124b may be
heated approximately fifteen degrees Fahrenheit as a result of the
desired removal of heat from load center 118. Thus, in the current
example, fluid 124b exiting load center 118 at load center outlet
162 may be approximately seventy degrees Fahrenheit. Fluid 124b
circulates though system pumps 122 and enters heat exchanger 114 at
heat exchanger inlet 164. Heat exchanger 114 cools fluid 124b as a
result of the transfer of heat to fluid 124a circulating from
filters 112. For example, heat exchanger 114 may cool fluid 124b
from system pumps 122 approximately fifteen degrees Fahrenheit.
Thus, fluid 124b exiting heat exchanger 114 at outlet 166 may be
approximately fifty-five degrees Fahrenheit in the current example,
which is the target temperature at load center inlet 160.
[0022] Fluid 124a circulating in free-cooling mode exits cooling
towers 108 at a particular temperature, T.sub.CT, based on the wet
bulb temperature and the cooling that occurs in cooling towers 108.
For example, fluid 124a exiting cooling towers 108 through cooling
tower outlet 158 may be at a temperature of approximately
fifty-three degrees Fahrenheit. Fluid 124a flows through tower
pumps 110 and filters 112 and enters heat exchanger 114 at heat
exchanger inlet 168. Heat exchanger 114 heats fluid 124a as a
result of the transfer of heat from fluid 124b circulating from
system pumps 122. For example, heat exchanger 114 may heat fluid
124a from filters 112 approximately fifteen degrees Fahrenheit.
Thus, fluid 124a exiting heat exchanger 114 at outlet 170 may be
approximately sixty-eight degrees Fahrenheit in the current
example. Since condenser 138 is not operating in this mode, fluid
124a may pass through condenser 138 and exit condenser 138 through
condenser outlet 156 or fluid 124a may bypass condenser 138 at
approximately the same temperature, for example, approximately
sixty-eight degrees Fahrenheit. Fluid 124a flows to cooling towers
108 and enters cooling towers 108 at cooling tower inlet 172. In
cooling towers 108, the temperature of fluid 124a decreases. For
example, cooling towers 108 may decrease the temperature of fluid
124a to approximately fifty-three degrees Fahrenheit in the current
example.
[0023] In circumstances where the wet bulb temperature is above a
selected T.sub.1, for example, approximately forty-nine degrees
Fahrenheit in the current example, cooling system 180 may operate
in pre-cooling mode. In pre-cooling mode, heat exchanger 114 is
configured to pre-cool fluid 124b prior to entering evaporator 136.
As such, the cooling provided by heat exchanger 114 and chiller 116
is combined to provide the necessary cooling of fluid 124b for load
center 118. Thus, the cooling to be accomplished by chiller 116 may
be minimized.
[0024] In some embodiments, cooling system 180 is configured to
operate pre-cooling mode a range of target wet bulb temperatures,
for example, from T.sub.2 to T.sub.1. For example, at a wet bulb
temperature greater than approximately forty-nine degrees
Fahrenheit (T.sub.2) and less than or equal to approximately
seventy-one degrees Fahrenheit (T.sub.1), pre-cooling mode may be
the most efficient cooling mode to operate. However, as the wet
bulb temperature rises above a specified T.sub.2, pre-cooling mode
may not be the proper cooling mode to operate because the required
cooling may not be provided. Additionally, operation in pre-cooling
mode may be based on the temperature of fluid 124a exiting cooling
tower 108 at cooling tower outlet 158, T.sub.CT. In some
embodiments, if T.sub.CT is less than the temperature of fluid 124b
at heat exchanger inlet 164, pre-cooling mode may be the most
efficient cooling mode to operate. For example, T.sub.CT may be
approximately seventy-four degrees Fahrenheit and the temperature
of fluid 124b at heat exchanger inlet 164 may be approximately
seventy-five degrees Fahrenheit. Thus, cooling system 180 may be
configured to transition from pre-cooling mode to another cooling
mode when the atmospheric conditions or other suitable parameters
indicate that pre-cooling mode is no longer able to provide
sufficient cooling. For exemplary purposes, the following
discussion of pre-cooling mode assumes a wet bulb temperature,
T.sub.WB, of approximately sixty-seven degrees Fahrenheit.
[0025] Pre-cooling mode circulates fluid 124a in first loop 104
through cooling towers 108, tower pumps 110, filters 112, heat
exchanger 114, and condenser 138, and circulates fluid 124b in
second loop 106 through evaporator 136, load center 118, system
pumps 122, and heat exchanger 114. Fluid 124a circulating in
pre-cooling mode exits cooling towers 108 at cooling tower outlet
158 at a particular temperature based on the wet bulb temperature
and the cooling that occurs in cooling towers 108. For example,
fluid 124a exiting cooling towers 108 through cooling tower outlet
158 may be at a temperature of approximately seventy degrees
Fahrenheit. Fluid 124a flows through tower pumps 110 and filters
112 and enters heat exchanger 114 at heat exchanger inlet 168. Heat
exchanger 114 heats fluid 124a as a result of the transfer of heat
from fluid 124b circulating from system pumps 122. For example,
heat exchanger 114 may heat fluid 124a from filters 112
approximately three degrees Fahrenheit. Thus, fluid 124a exiting
heat exchanger 114 at heat exchanger outlet 170 may be
approximately seventy-three degrees Fahrenheit in the current
example. Because chiller 116 is operating, fluid 124a may absorb
heat as it travels through condenser 138 and exits condenser 138
through condenser outlet 156 at approximately ninety degrees
Fahrenheit. Fluid 124a flows to cooling towers 108 and enters
cooling towers 108 at cooling tower inlet 172. In cooling towers
108, the temperature of fluid 124a decreases. For example, cooling
towers 108 may decrease the temperature of fluid 124a to
approximately seventy degrees Fahrenheit in the current
example.
[0026] Fluid 124b circulating in pre-cooling mode exits evaporator
136 through evaporator outlet 152 at a temperature of approximately
fifty-five degrees Fahrenheit for example. Fluid 124b circulates
through load center 118 and absorbs heat of a desired number of
degrees. For example, fluid 124b may be heated approximately twenty
degrees Fahrenheit as a result of the desired removal of heat from
load center 118. Thus, in the current example, fluid 124b exiting
load center 118 at load center outlet 162 may be approximately
seventy-five degrees Fahrenheit. Fluid 124b circulates though
system pumps 122 to enter heat exchanger 114 at heat exchanger
inlet 164. Heat exchanger 114 cools fluid 124b as a result of the
transfer of heat to fluid 124a circulating from filters 112. For
example, heat exchanger 114 may cool fluid 124b from system pumps
122 approximately three degrees Fahrenheit. Thus, fluid 124b
exiting heat exchanger 114 at heat exchanger outlet 166 may be
approximately seventy-two degrees Fahrenheit in the current
example. Fluid 124b enters evaporator 136 at evaporator inlet 150
and is cooled by heat removal to exit evaporator outlet 152 at
approximately fifty-five degrees Fahrenheit.
[0027] Accordingly, in some embodiments, pre-cooling mode may
utilize heat transfer from both heat exchanger 114 and chiller 116
in series to accomplish the desired removal of heat from fluid
124b. Additionally, adjusting the flow rate of fluid 124b by system
pumps 122 may increase or decrease the amount of heat removal as
fluid 124b flows through heat exchanger 114 and chiller 116. For
example, by decreasing the flow rate of fluid 124b more heat may be
removed as fluid 124b flows through heat exchanger 114 and chiller
116.
[0028] In mechanical-cooling mode, chiller 116 provides all or
nearly all of cooling for cooling system 180. Cooling system 180 is
configured to operate mechanical-cooling mode above a target wet
bulb temperature, T.sub.2. For example, at a target wet bulb
temperature greater than approximately seventy-one degrees
Fahrenheit (T.sub.2), mechanical-cooling mode may be the most
efficient cooling mode to operate. However, as the wet bulb
temperature decreases below T.sub.2, mechanical-cooling mode may
not be the most efficient cooling mode to operate because one
hundred percent mechanical cooling provided by chiller 116 requires
more energy than free cooling provided by cooling towers 108.
Additionally, operation in mechanical-cooling mode may be based on
the temperature of fluid 124a exiting cooling tower 108 at cooling
tower outlet 158, T.sub.CT. In some embodiments, if T.sub.CT is
greater than or equal to the temperature of fluid 124b at heat
exchanger inlet 164, mechanical-cooling mode may be the most
efficient cooling mode to operate. For example, T.sub.CT may be
approximately seventy-five degrees Fahrenheit and the temperature
of fluid 124b at heat exchanger inlet 164 may be approximately
seventy-five degrees Fahrenheit. Thus, cooling system 180 is
configured to transition from mechanical-cooling mode to another
cooling mode when the atmospheric conditions or other suitable
parameters indicate that mechanical-cooling mode is no longer
necessary. For exemplary purposes, the following discussion of
mechanical-cooling mode assumes a T.sub.WB of approximately
seventy-three degrees Fahrenheit.
[0029] Mechanical-cooling mode circulates fluid 124a in first loop
104 through tower pumps 110, filters 112, heat exchanger 114, and
condenser 138, and circulates fluid 124b in second loop 106 through
evaporator 136, load center 118, system pumps 122, and heat
exchanger 114. Fluid 124a circulating in mechanical-cooling mode
exits cooling towers 108 at a particular temperature based on the
wet bulb temperature and the cooling that occurs in cooling towers
108. For example, fluid 124a may exit cooling towers 108 through
cooling tower outlet 158 may be at a temperature of approximately
seventy-five degrees Fahrenheit. Fluid 124a flows through tower
pumps 110 and filters 112 and enters heat exchanger 114 at heat
exchanger inlet 168. Because the temperature of fluid 124a may be
approximately equivalent to the temperature of fluid 124b, heat
exchanger 114 may not provide any heat transfer from fluid 124a to
fluid 124b, or in circumstances in which the temperature of fluid
124a is greater than the temperature of fluid 124b, heat may be
transferred from fluid 124a to fluid 124b. In such a case, heat
exchanger 114 may be bypassed by utilizing one or more bypass
valves. In the current example, fluid 124a may exit heat exchanger
114 at heat exchanger outlet 170 at approximately the same
temperature as fluid 124a entered heat exchanger 114, approximately
seventy-five degrees Fahrenheit. Because chiller 116 is operating,
fluid 124a may absorb heat as it travels through condenser 138 and
exit condenser 138 through condenser outlet 156 at approximately
ninety-five degrees Fahrenheit. Fluid 124a flows to cooling towers
108 and enters cooling towers 108 at cooling tower inlet 172. In
cooling towers 108, the temperature of fluid 124a decreases. For
example, cooling towers 108 may decrease the temperature of fluid
124a to approximately seventy-five degrees Fahrenheit in the
current example.
[0030] Fluid 124b circulating in mechanical-cooling mode exits
evaporator 136 through evaporator outlet 152 at a temperature of
approximately fifty-five degrees Fahrenheit for example. Fluid 124b
circulates through load center 118 and absorbs heat of a desired
number of degrees. For example, fluid 124b may be heated
approximately twenty degrees Fahrenheit as a result of the desired
removal of heat from load center 118. Thus, in the current example,
fluid 124b exiting load center 118 at load center outlet 162 may be
approximately seventy-five degrees Fahrenheit. Fluid 124b
circulates though system pumps 122 to enter heat exchanger 114 at
heat exchanger inlet 164. Because the temperature of fluid 124a may
be approximately equivalent to the temperature of fluid 124b, heat
exchanger 114 may not provide any heat transfer from fluid 124a to
fluid 124b. Thus, fluid 124b exiting heat exchanger 114 at outlet
166 may be approximately seventy-five degrees Fahrenheit in the
current example. Fluid 124b enters evaporator 136 at evaporator
inlet 150 and is cooled by heat removal to exit at evaporator
outlet 152 at approximately fifty-five degrees Fahrenheit.
[0031] In some embodiments, some or all of free-cooling,
pre-cooling, and mechanical-cooling modes may be included in a
cooling system. The selection of the appropriate cooling mode may
be based on a wet bulb temperature, target inlet fluid temperatures
for any load centers, or the temperature of a fluid exiting a
cooling tower in a cooling system.
[0032] Cooling towers 108 may be high efficiency designs with
induced draft fans. In alternate embodiments, cooling towers 108
utilize other designs and configurations that perform the same or
similar function. Cooling towers 108 use induced draft fans to draw
or blow atmospheric air 130 through an atmospheric air inlet. The
induced draft fan may be a fixed speed fan or a variable speed fan.
Cooling towers 108 are open to the exterior environment and exposed
to the external atmosphere. Atmospheric air 130 may interact with
fluid 124a that enters cooling towers 108 via return piping. As the
fluid 124a exiting the return piping mixes with the atmospheric
air, the latent heat of vaporization is absorbed from fluid 124a
and the atmospheric air. As a result, fluid 124a is cooled. Cooling
towers 108 may additionally include temperature sensors, flow rate
meters, pressure sensors, or any other suitable components to allow
for monitoring and control of cooling towers 108.
[0033] The rate and amount of cooling performed within cooling
towers 108 depends on the wet bulb characteristics of the
atmospheric air. Generally, the lower the wet bulb temperature of
the atmospheric air, the more cooling capacity that can take place
within cooling towers 108. As example, cooling towers 108 may be
four degree approach cooling towers, which indicate that the
temperature of fluid 124a is approximately four degrees higher than
the wet bulb temperature after it passes through cooling towers
108.
[0034] After the atmospheric air absorbs heat within cooling towers
108, the atmospheric air exhausts to the atmosphere through
atmospheric air exhaust 132 included in cooling towers 108. In some
embodiments, atmospheric air exhaust 132 is located in cooling
towers 108 opposite from an atmospheric air inlet to form a defined
flow path of atmospheric air through cooling towers 108. In
alternate embodiments, the location of atmospheric air exhaust 132
may vary. Just as the atmospheric air exhausts from cooling towers
108, fluid 124a that has been cooled, also exits cooling towers 108
at cooling tower outlet 158.
[0035] One or more temperature sensors are coupled to portions of
cooling system 180. The temperature sensors are utilized to sense
the temperature of fluids 124 or atmospheric air 130. The
temperature sensors are communicatively coupled to processing
system 126 such that readings from the temperature sensors may be
utilized to determine which cooling mode should be utilized.
[0036] Additionally, one or more valves may be fluidically
connected or coupled via piping to portions of cooling system 180.
Valves may include one or more two-way or three-way valves to
direct the flow of fluids 124. Further, valves may be
electronically controlled and coupled with other devices, such as
flow rate meters, to direct fluids 124. Valves may additionally
include temperature sensors, pressure sensors, or any other
suitable components to allow for monitoring and control of fluids
124.
[0037] In some embodiments, cooling towers 108 are fluidically
connected or coupled via piping to tower pumps 110. After fluid
124a is cooled in cooling towers 108, fluid 124a accumulates within
cooling towers 108 and tower pumps 110 pump fluid 124a through
tower pumps 110. Tower pumps 110 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 is
designated as an operating tower pump while additional pumps are
designated as standby pumps. Thus, the operating pump normally
pumps fluid 124, while the standby pump remains in a standby mode
in case the operating pump fails or another system condition
requires the use of the standby pump. In alternate embodiments,
tower pumps 110 are configured in series or a single pump is
utilized.
[0038] Tower pumps 110 may be variable speed, thus allowing
variable flow and pressure, or fixed speed pumps. Tower pumps 110
may be configured to maintain a consistent flow such as defined
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 approximately forty-five
hp and generate a flow of approximately 1,250 GPM. Tower pumps 110
may additionally include flow rate meters, pressure sensors, or any
other suitable components to allow for monitoring and control of
tower pumps 110.
[0039] Tower pumps 110 circulate fluid 124a through various
components and subsystems of cooling system 180. Tower pumps 110
are fluidically connected or coupled via piping to filters 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 filters 112 such that at least a portion of
fluid 124a circulates through the chemical treatment and monitoring
subsystem prior to entering to filters 112. The portion of fluid
that enters the chemical treatment and monitoring subsystem is
controlled by one or more valves. The valves may be electronically
controlled and coupled with other devices, such as flow rate
meters, to direct suitable portions of the fluid 124a to the
chemical treatment and monitoring subsystem in order to maintain
consistent chemical properties in the fluid 124a. The chemical
treatment and monitoring subsystem chemically treats fluid 124a to
maintain optimum water quality. Additionally, a dedicated chemical
subsystem pump or alternate pressure source circulates the portion
of fluid 124a that enters the chemical treatment and monitoring
subsystem.
[0040] Tower pumps 110 circulate fluid 124a to enter filters 112
either directly or once fluid 124a or a portion of fluid 124a is
processed through the chemical treatment and monitoring subsystem.
Filters 112 filter fluid 124a before it enters heat exchanger 114.
Filters 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 fluid 124a. In some embodiments, filters 112
substantially prevent a particle of a predetermined size or larger
from circulating with fluid 124a through the portion of cooling
system 180 following filters 112. Filters 112 may additionally
include flow rate meters, pressure sensors, or any other suitable
components to allow for monitoring and control of filters 112.
[0041] Heat exchanger 114 is fluidically connected or coupled via
piping to cooling towers 108, filters 112, chiller 116, load center
118, and/or system pumps 122. Heat exchanger 114 may be a high
efficiency counter-flow design. In alternate embodiments, heat
exchanger 114 utilizes other designs and configurations that
perform the same or similar function. Heat exchanger 114 has
separate inlets and separate paths for fluid 124a from filters 112
and fluid 124b from system pumps 122. As different temperature
fluids 124 from filters 112 and system pumps 122 travels through
heat exchanger 112 in separate paths, heat from the higher
temperature fluid, for example fluid 124b from system pumps 122,
transfers to the lower temperature fluid, for example, fluid 124a
from filters 114. Heat exchanger 112 may additionally include
temperature sensors, flow rate meters, pressure sensors, and any
other suitable components to allow for monitoring and control of
heat exchanger 112. The rate and amount of cooling performed within
heat exchanger 112 may depend on the design and specifications of
heat exchanger 112, the temperatures of fluids 124, and the flow
rates of fluids 124.
[0042] In some embodiments, chiller 116 may be utilized to chill
fluid 124b. Chiller 116 may include evaporator 136 and condenser
138. Condenser 138 may be configured to absorb heat from fluid 124b
flowing through evaporator 136. Fluid 124a may enter condenser 138
at condenser inlet 154 and may exit condenser 138 at condenser
outlet 156. 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, or any other suitable components to
allow for monitoring and control of condenser 138.
[0043] Evaporator 136 may be configured to work in connection with
condenser 138. Evaporator 136 may condition fluid 124b to a
predetermined temperature, such as approximately fifty-five degrees
Fahrenheit. Fluid 124b may enter evaporator 136 at evaporator inlet
150 and may exit evaporator 136 at evaporator outlet 152. Fluid
124b enters evaporator 138 and may be at a temperature greater than
a target fluid temperature for load center 118, for example,
approximately seventy-two degrees Fahrenheit. Evaporator 136 may
lower the temperature of fluid 124b to the target fluid temperature
for load center 118. Evaporator 136 may additionally include
temperature sensors, flow rate meters, pressure sensors, or any
other suitable components to allow for monitoring and control of
evaporator 136.
[0044] Load center 118 includes any equipment, machinery, and
personnel that generate heat during operation. Load center 118 is
designed to maintain a particular environment for the protection of
equipment and machinery included in load center 118. For example,
load center 118 may be a data center designed to maintain a supply
air temperature of approximately sixty-five degrees Fahrenheit and
a humidity level below a certain threshold, such as approximately
sixty percent. Load center 118 may additionally include temperature
sensors, flow rate meters, pressure sensors, or any other suitable
components to allow for monitoring and control of load center
118.
[0045] In some embodiments, load center 118 may include multiple
air-handler units 140, and humidification elements 142. Air-handler
units 140 may provide an interface between fluid 124b cooled by
heat exchanger 114 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. Fluid 124b may enter load center 118 via piping, for
example a cooling coil, that directs fluid 124b proximate to
air-handler units 140 or heated data center load air 144. As fluid
124b passes proximate to air-handler units 140 or heated data
center load air 144, to air-handler units 140 may cause the heat in
the data center air to transfer to fluid 124b. For example,
air-handler units 140 in the form of fans may blow load air 144
across the piping that contains fluid 124b. Thus, fluid 124b that
exits data center 118 may be at a higher temperature than fluid
124b that enters data center 118. The data center air that has been
cooled may be directed by the air-handler units 140 back through
data center 118. Fluid 124b, which has been heated, may be directed
via piping to system pumps 122.
[0046] 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.
[0047] In some embodiments, cooling system 180 may utilize 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 fluid 124b, 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, 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.
[0048] In some embodiments, fluid 124a that circulates in first
loop 104 may be cooling water. Fluid 124b that circulates in second
loop 106 may be water, glycol, Freon, refrigerant, or any other
suitable cooling fluid.
[0049] Components of cooling configuration 100 include processing
system 126. Processing system 126 includes 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, other form of computer, a
network storage resource, or any other suitable device and may vary
in size, shape, performance, functionality, and price.
[0050] Processing system 126 includes 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 data, execute program
instructions, or process data. A processing resource may interpret
or execute program instructions and process data stored in memory,
mass storage device, or another component of cooling configuration
100.
[0051] Processing system 126 includes any system, device, or
apparatus operable to retain program instructions or data for a
period of time (for example, 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 or array of volatile or non-volatile
memory that retains data after power to processing system 126 is
removed.
[0052] Processing system 126 includes 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 (for
example, computer-readable media). Storage resources 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
any computer-readable medium operable to store data.
Computer-readable media include any instrumentality or aggregation
of instrumentalities that may retain data and instructions for a
period of time. Computer-readable media may include, without
limitation, storage media such as a direct access storage device
(for example, a hard disk drive or floppy disk), a sequential
access storage device (for example, a tape disk drive), compact
disk, CD-ROM, DVD, random access memory (RAM), read-only memory
(ROM), electrically erasable programmable read-only memory
(EEPROM), or flash memory; as well as communications media such
wires, optical fibers, microwaves, radio waves, and other
electromagnetic or optical carriers; or any combination of the
foregoing.
[0053] 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
any component of cooling system 180.
[0054] Processing system 126 is operable to receive data from, and
transmit data to, any component of cooling system 180 or other
processing systems. Processing system 126 may be a host computer, a
remote system, and 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.
[0055] FIG. 2 illustrates an example psychometric chart 200 showing
an exemplary cooling process utilizing a multiple mode cooling
system in accordance with certain embodiments of the present
disclosure. The psychometric chart illustrates psychometric
properties of the atmospheric air 130 prior to entering cooling
system 180. For example, atmospheric air 130 entering cooling
towers 108 shown with reference to FIG. 1. Psychometric chart 200
may be based on a cooling system designed to deliver approximately
fifty-five degree Fahrenheit fluid 124b to load center 118.
Psychometric chart 200 may further be based on a heat load at load
center 118 of approximately fifteen to twenty degrees
Fahrenheit.
[0056] Additionally, psychometric chart 200 may be based on an
approach temperature for cooling tower 108 and heat exchanger 114.
For example, cooling towers 108 may be three degree Fahrenheit
approach cooling towers and heat exchanger 114 may be a two degree
Fahrenheit approach heat exchanger. However, modifications may be
made to psychometric chart 200, for example, locations of T.sub.1
line 202 and T.sub.2 line 204 based on a different designed
delivery temperature of fluids 124, a different heat load at load
center 118, a different cooling towers 108 approach temperature, or
a different heat exchanger 114 approach temperature.
[0057] In some embodiments, the psychometric zone below T.sub.1
line 202 corresponds to exterior air properties that enable
free-cooling mode to be the most efficient operating mode for
cooling system 180. For example, T.sub.1 line 202 corresponds to
wet bulb temperature of approximately forty-nine degrees
Fahrenheit. For free-cooling mode, cooling towers 108 provide
approximately one hundred percent cooling as discussed above with
reference to FIG. 1.
[0058] The psychometric zone less than or equal to T.sub.2 line 204
and greater than T.sub.1 line 202 corresponds to exterior air
properties that enable the pre-cooling mode to be the most
efficient. As example, T.sub.2 line 204 corresponds to a wet bulb
temperature of approximately seventy-one degrees Fahrenheit. Thus,
at wet bulb temperatures below approximately seventy-one and
greater than approximately forty-nine degrees Fahrenheit,
pre-cooling mode may be the most appropriate mode of operating
cooling system 180.
[0059] In some embodiments, the psychometric zone above T.sub.2
line 204 corresponds to exterior air properties that enable
mechanical-cooling mode to be the most proper operating mode for
cooling system 180. For example, T.sub.2 line 204 corresponds to
wet bulb temperature of approximately seventy-one degrees
Fahrenheit. For mechanical-cooling mode, cooling chiller 116
provides cooling as discussed above with reference to FIG. 1.
[0060] Accordingly, energy efficiencies may occur through
utilization of pre-cooling mode at the appropriate wet bulb
temperatures because heat exchanger 114 may offset a portion of the
load. As an example, Table 1 illustrates the approximate load
carried by an approximately 825 ton chiller 116 at particular wet
bulb temperatures that may occur in operation of pre-cooling mode
in cooling system 180 with an approximately 625 ton load at load
center 118.
TABLE-US-00001 TABLE 1 Wet Bulb Temperature Load on Chiller 116
(degrees Fahrenheit) (tons) Less than or equal to 49 0 51 degrees
Fahrenheit 83 55 degrees Fahrenheit 250 59 degrees Fahrenheit 281
63 degrees Fahrenheit 437 67 degrees Fahrenheit 530 71 degrees
Fahrenheit 593 75 degrees Fahrenheit 655
[0061] In determining design parameters for cooling system 180 of
FIG. 1, 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.
[0062] As an 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 625 tons, e.g.,
heat to be dissipated at load center 118. Cooling tower 108 may be
designed as a three 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 forty-five horsepower pumps with a flow rate that may
range from approximately 750 GPM to 1,000 GPM. Chiller 116 may be a
825 ton chiller manufactured by Trane, an Ingersoll Rand company
(Davidson, N.C.). Chiller 116 flow rate may be approximately 2.0
GPM/ton. Fluid 124b target temperature for load center 118 may be
approximately fifty-five degrees Fahrenheit.
[0063] During operation of the current example, a psychometric
chart, such as psychometric chart 200, for the designed system may
place T.sub.1 line 202 at approximately forty-nine degrees. The
designed system may place T.sub.2 line 204 at approximately
seventy-one degrees Fahrenheit. For approximately fifty-seven
percent of the hours in each year, the wet bulb temperature may be
lower than approximately forty-nine degrees Fahrenheit. Thus,
cooling system 180 may be configured to operate in free-cooling
mode. Chiller 116 may be turned off or bypassed in operation of
free-cooling mode.
[0064] For an additional approximately forty-one percent of the
hours in each year, the wet bulb temperature may be lower than
approximately seventy-one degrees Fahrenheit. Pre-cooling mode may
be useful to operate at these wet bulb temperatures. Operating
pre-cooling mode may offset the cooling that chiller 116 needs to
accomplish.
[0065] In the current example, the location may experience
approximately two percent of the hours in each year with a wet bulb
temperature over approximately seventy-three degrees Fahrenheit.
Mechanical-cooling mode may be the proper mode to operate at these
wet bulb temperatures. As such, chiller 116 may be operating at a
high capacity in mechanical-cooling mode.
[0066] 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 191 hours of
mechanical-cooling mode operation, 3,602 hours of pre-cooling mode
operation, and 4,967 hours of free-cooling mode operation. A
typical system may run approximately 625 tons of cooling year round
(8,760 hours) using mechanical-cooling mode exclusively and consume
approximately 3,611,047 kilowatt-hours of energy. Using the
pre-cooling mode and free-cooling mode, the resultant annual energy
consumption may be approximately 972,763 kilowatt-hours of energy
resulting in an approximately seventy-three percent (73%) decrease
in cooling consumption and cost.
[0067] FIG. 3 illustrates a flow chart for an example method for
cooling system transitions using multiple cooling modes in
accordance with certain embodiments of the present disclosure. The
steps of method 300 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
300 may be executed by processing system 126, an operator of the
cooling system, and/or other suitable source. For illustrative
purposes, method 300 may be described with respect to cooling
system 180 of FIG. 1; however, method 300 may be used for cooling
system transitions using hybrid cooling system of any suitable
configuration.
[0068] At step 305, the processing system obtains a temperature at
a cooling tower. For example, with reference to FIG. 1, a
temperature sensor senses the wet bulb temperature of atmospheric
air 130 at cooling tower 108. In some embodiments, the processing
system may obtain the temperature of fluid 124a that exits cooling
tower 108, T.sub.CT.
[0069] At step 310, the processing system determines if the
obtained temperature is less than or equal to a first preset
temperature. For example, processing system 126 determines if the
wet bulb temperature atmospheric air 130 is less than or equal to
T.sub.1 discussed with reference to FIGS. 1 and 2. T.sub.1 is based
on design considerations, atmospheric conditions, sizes and loads
on components in the cooling system, or any other suitable factor.
T.sub.1 may be the temperature at which it becomes more efficient
to operate cooling system in free-cooling mode. For example, with
reference to FIG. 1, T.sub.1 may be set at approximately forty-nine
degrees Fahrenheit. As another example, when the obtained
temperature is the temperature of fluid 124a exiting cooling tower
108, it may be determined that the temperature is less than or
equal to approximately fifty-five degrees Fahrenheit. If the
obtained temperature is less than or equal to a preset temperature,
then method 300 proceeds to step 315. If the obtained temperature
is greater than the preset temperature, method 300 proceeds to step
320.
[0070] At step 315, the processing system configures the cooling
system to operate in free-cooling mode. Free-cooling mode may
include configuring a heat exchanger to provide approximately all
of the heat transfer required to cool a load center. Free-cooling
mode may also include configuring a chiller to be non-operational
or bypassed. For example, with reference to FIG. 1, processing
system 126 turns off chiller 116 or electronically configures
valves to direct fluids 124 to bypass chiller 116. After step 315,
method 300 returns to step 305.
[0071] At step 320, the processing system determines if the
obtained temperature is less than or equal to a second preset
temperature. For example, processing system 126 determines if the
temperature atmospheric air 130 is less than or equal to T.sub.2.
T.sub.2 is based on design considerations, atmospheric conditions,
sizes and loads on components in the cooling system, or any other
suitable factor. T.sub.2 may be the temperature at which it becomes
necessary to operate the cooling system in mechanical-cooling mode.
For example, with reference to FIG. 1, T.sub.2 may be set at
approximately seventy-one degrees Fahrenheit. As another example,
when the obtained temperature is the temperature of fluid 124a
exiting cooling tower 108, it may be determined that the
temperature is less than or equal to approximately seventy-five
degrees Fahrenheit. If the obtained temperature is less than or
equal to a second preset temperature, then method 300 proceeds to
step 325. If the obtained temperature is greater than the second
preset temperature, method 300 proceeds to step 330.
[0072] At step 325, the processing system configures the cooling
system to operate pre-cooling mode. Pre-cooling mode may include
configuring a heat exchanger to provide a portion of the heat
transfer required to cool a load center. Pre-cooling mode may also
include configuring a chiller to operate at less than full
capacity. For example, with reference to FIG. 1, processing system
126 turns on chiller 116 or electronically configures valves to
direct fluids 124 to chiller 116. After step 325, method 300
returns to step 305.
[0073] At step 330, the processing system configures the cooling
system to operate mechanical-cooling mode. Mechanical-cooling mode
may include configuring a chiller to be operated at an elevated
capacity or to be operated to provide approximately all of the
cooling for a load center. Mechanical-cooling mode may also include
configuring valves to bypass heat exchanger 114. For example, with
reference to FIG. 1, processing system 126 turns on chiller 116 or
electronically configures valves to direct fluids 124 to chiller
116. After step 330, method 300 returns to step 305.
[0074] Modifications, additions, or omissions may be made to method
300 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 310 and step 320 may
be performed simultaneously. Additionally, each individual step may
include additional steps without departing from the scope of the
present disclosure. For example, step 315 may be preformed before
or after step 310 without departing from the scope of the present
disclosure.
[0075] 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.
* * * * *