U.S. patent application number 15/011386 was filed with the patent office on 2017-08-03 for dynamic cycle air conditioner with incremental dehumidification and stored water maintained at a temperature lower than the environment.
The applicant listed for this patent is Ali Mohammad Bujsaim. Invention is credited to Anas Youssef Boubas, Ali Mohammad Bujsaim.
Application Number | 20170219229 15/011386 |
Document ID | / |
Family ID | 59386492 |
Filed Date | 2017-08-03 |
United States Patent
Application |
20170219229 |
Kind Code |
A1 |
Bujsaim; Ali Mohammad ; et
al. |
August 3, 2017 |
DYNAMIC CYCLE AIR CONDITIONER WITH INCREMENTAL DEHUMIDIFICATION AND
STORED WATER MAINTAINED AT A TEMPERATURE LOWER THAN THE
ENVIRONMENT
Abstract
Water temperature conservation for increasing efficiency of an
indirect evaporative cooling apparatus. A heat exchanger of the
indirect evaporative cooling apparatus includes a dry passage
separated from a wet passage by a membrane, the dry passage
including an intake portion, an outlet portion, and a loop portion.
Water captured from condensation during a dehumidification process
can be stored and/or used to wet the wet passage of the heat
exchanger to enhance evaporative function. Stored water can be
maintained at a relatively lower temperature than the environment,
helping to maintain a lower internal apparatus temperature and to
further cool circulating air.
Inventors: |
Bujsaim; Ali Mohammad;
(Dubai, AE) ; Boubas; Anas Youssef; (Santa Clara,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Bujsaim; Ali Mohammad |
Dubai |
|
AE |
|
|
Family ID: |
59386492 |
Appl. No.: |
15/011386 |
Filed: |
January 29, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F28F 1/04 20130101; F24F
1/0007 20130101; F28D 5/02 20130101; Y02B 30/54 20130101; F28F
25/06 20130101; F28F 2245/02 20130101; F28F 27/02 20130101; F28F
2025/005 20130101; Y02B 30/545 20130101; F28F 17/005 20130101; F28F
2245/04 20130101; F28D 3/04 20130101; F28D 1/0477 20130101; F24F
5/0035 20130101 |
International
Class: |
F24F 5/00 20060101
F24F005/00; F28D 3/02 20060101 F28D003/02; F28F 25/06 20060101
F28F025/06; F28D 3/04 20060101 F28D003/04; F28F 1/04 20060101
F28F001/04; F24F 11/02 20060101 F24F011/02; F24F 13/22 20060101
F24F013/22 |
Claims
1. An indirect evaporative cooler apparatus comprising: a heat
exchanger comprising a dry passage and a wet passage, the wet
passage comprising a nozzle coupled with an evaporative liquid
reservoir and configured to wet the wet passage, the dry passage in
thermodynamic communication with the wet passage and separated from
the wet passage by a substantially liquid-impermeable membrane
having a hydrophobic surface facing the dry passage and a
hydrophilic surface facing the wet passage, the dry passage
comprising an intake portion, an outlet portion, and a loop
portion; a mixing valve disposed in the dry passage and configured
to selectively pass intake air from the intake portion,
recirculation air from the loop portion, or a combination thereof;
a first fan disposed downstream of the mixing valve and adapted to
move air into and through the loop portion; a diverting valve
disposed in the dry passage and configured to selectively pass
outlet air to the outlet portion, recirculation air to the mixing
valve, or a combination thereof; and a controller adapted to
operate the mixing valve, the first fan, the diverting valve, and a
combination thereof, to move a first volume of air through the dry
passage while dispensing evaporative liquid having a first
temperature through the nozzle onto the hydrophilic surface to cool
and dehumidify the first volume of air, and to dispense collected
water condensed from the dehumidification of the first volume of
air onto the hydrophilic surface to cool and dehumidify a second
volume of air.
2. The apparatus of claim 1, wherein the collected water is stored
in an internal liquid reservoir disposed within a housing that
contains the heat exchanger and coupled with the nozzle.
3. The apparatus of claim 2, wherein the controller is adapted to
increase pressure in the internal liquid reservoir to dispense the
collected water upon detection of the collected water temperature
being at or below a threshold value.
4. The apparatus of claim 1, wherein the collected water is stored
in the evaporative liquid reservoir.
5. The apparatus of claim 1, further comprising a dry passage water
nozzle configured to expel accumulated water from dehumidification
of the first volume of air.
6. A method of conserving water temperature for cooling air in an
indirect evaporative cooler, the method comprising: having a heat
exchanger comprising a dry passage and a wet passage, the dry
passage in thermodynamic communication with the wet passage and
separated from the wet passage by a substantially
liquid-impermeable membrane having a hydrophobic surface facing the
dry passage and a hydrophilic surface facing the wet passage, the
dry passage comprising an intake portion, an outlet portion, and a
loop portion; moving a first volume of air through the dry passage
while dispensing an evaporative liquid having a first temperature
onto the hydrophilic surface to cool and dehumidify the first
volume of air; collecting water condensed from the dehumidification
of the first volume of air; and dispensing the collected water onto
the hydrophilic surface to cool and dehumidify a second volume of
air.
7. The method of claim 6, wherein collecting water comprises
storing in an external reservoir operable to also store the
evaporative liquid.
8. The method of claim 6, wherein collecting water comprises
storing in an internal reservoir disposed within a housing that
contains the heat exchanger.
9. The method of claim 8, wherein the dispensing comprises
directing the collected water via a supply pipe to a wet passage
nozzle, the supply pipe having an associated pressure valve for
maintaining a dispensing rate.
10. The method of claim 9, wherein the dispensing is controlled to
occur when the collected water has a second temperature that is
lower than the first temperature.
11. A system for conserving water temperature for cooling air, the
system comprising: an evaporative liquid reservoir comprising a
pressure valve and a channel adapted to transport evaporative
liquid; a heat exchanger comprising: a dry passage and a wet
passage, the dry passage in thermodynamic communication with the
wet passage and separated from the wet passage by a substantially
liquid-impermeable membrane having a hydrophobic surface facing the
dry passage and a hydrophilic surface facing the wet passage, the
dry passage comprising an intake portion, an outlet portion, and a
loop portion; a nozzle coupled with the channel and configured to
wet the wet passage for evaporative cooling of the substantially
liquid-impermeable membrane; a mixing valve disposed in the dry
passage and configured to selectively pass intake air from the
intake portion, recirculation air from the loop portion, or a
combination thereof; a first fan disposed downstream of the mixing
valve and adapted to move a first volume of air into and through
the loop portion; and a diverting valve disposed in the dry passage
and configured to selectively pass outlet air to the outlet
portion, recirculation air to the mixing valve, or a combination
thereof; and a controller adapted to operate the mixing valve, the
first fan, the diverting valve, and a combination thereof, to move
a first volume of air through the dry passage while dispensing
evaporative liquid having a first temperature through the nozzle
onto the hydrophilic surface to cool and dehumidify the first
volume of air, and to dispense collected water condensed from the
dehumidification of the first volume of air onto the hydrophilic
surface to cool and dehumidify a second volume of air.
12. The system of claim 11, wherein the collected water is stored
in an internal liquid reservoir disposed within a housing that
contains the heat exchanger and coupled with the nozzle.
13. The system of claim 12, wherein the controller is adapted to
increase pressure in the internal liquid reservoir to dispense the
collected water upon detection of the collected water temperature
being at or below a threshold value.
14. The system of claim 11, wherein the collected water is stored
in the evaporative liquid reservoir.
15. The system of claim 11, further comprising a dry passage water
nozzle configured to expel accumulated water from dehumidification
of the first volume of air.
Description
FIELD OF THE INVENTION
[0001] Embodiments according to the present disclosure generally
relate to air conditioning and, more specifically, to an indirect
evaporative air conditioning system incorporating
dehumidification.
BACKGROUND OF THE INVENTION
[0002] Direct evaporative coolers, employing the thermodynamic
principle of adiabatic saturation, are well-known in the art. Air
to be cooled is saturated with an evaporative liquid (e.g., a water
mist), whose evaporation from the liquid state (mist) to vapor
state takes up available (latent) heat energy from the air itself,
thereby lowering its temperature. The ambient air may be cooled in
the limit to its wet bulb temperature using direct evaporative
cooling, the wet bulb temperature also being known as the adiabatic
saturation temperature. A problem with direct evaporative cooling
is the introduction of humidity into the cooled environmental
space, making this method of cooling unsuitable for sustained
cooling of a confined habitable space because continuous
humidification of the air causes discomfort to occupants.
[0003] A different method of cooling air is termed indirect
evaporative cooling, which functions by evaporating a cooling
liquid, usually water, into a first air stream while transferring
heat from a second air stream to the first air stream. Conventional
indirect evaporative coolers have traditionally been more expensive
than their evaporative counterparts. In particular, inefficiencies
in the transfer of heat from the second air stream to the first air
stream in conventional systems prevent sufficient cooling of air at
a similar cost to evaporative coolers. These inefficiencies can be
the result of a poor water supply system and/or expensive heat
exchanger materials, air flow pressure issues, a large number of
components that are auxiliary to the indirection evaporative
cooling system, etc.
SUMMARY OF THE INVENTION
[0004] This Summary is provided to introduce a selection of
concepts in a simplified form that are further described below in
the Detailed Description. This Summary is not intended to identify
key features or essential features of the claimed subject matter,
nor is it intended to be used to limit the scope of the claimed
subject matter.
[0005] An embodiment of the present disclosure includes water
temperature conservation for increasing efficiency of an indirect
evaporative cooling apparatus. A heat exchanger of the indirect
evaporative cooling apparatus includes a dry passage separated from
a wet passage by a membrane, the dry passage including an intake
portion, an outlet portion, and a loop portion. Water captured from
condensation during a dehumidification process can be stored and/or
used to wet the wet passage of the heat exchanger to enhance
evaporative function. Stored water can be maintained at a
relatively lower temperature than the environment, helping to
maintain a lower internal apparatus temperature and to further cool
circulating air.
[0006] More specifically, an aspect of the present disclosure
provides an indirect evaporative cooler apparatus including: a heat
exchanger comprising a dry passage and a wet passage, the wet
passage comprising a nozzle coupled with an evaporative liquid
reservoir and configured to wet the wet passage, the dry passage in
thermodynamic communication with the wet passage and separated from
the wet passage by a substantially liquid-impermeable membrane
having a hydrophobic surface facing the dry passage and a
hydrophilic surface facing the wet passage, the dry passage
comprising an intake portion, an outlet portion, and a loop
portion; a mixing valve disposed in the dry passage and configured
to selectively pass intake air from the intake portion,
recirculation air from the loop portion, or a combination thereof;
a first fan disposed downstream of the mixing valve and adapted to
move air into and through the loop portion; a diverting valve
disposed in the dry passage and configured to selectively pass
outlet air to the outlet portion, recirculation air to the mixing
valve, or a combination thereof; and a controller adapted to
operate the mixing valve, the first fan, the diverting valve, and a
combination thereof, to move a first volume of air through the dry
passage while dispensing evaporative liquid having a first
temperature through the nozzle onto the hydrophilic surface to cool
and dehumidify the first volume of air, and to dispense collected
water condensed from the dehumidification of the first volume of
air onto the hydrophilic surface to cool and dehumidify a second
volume of air.
[0007] In an embodiment of the indirect evaporative cooling
apparatus the collected water is stored in an internal liquid
reservoir disposed within a housing that contains the heat
exchanger and coupled with the nozzle. In an embodiment the
controller is adapted to increase pressure in the internal liquid
reservoir to dispense the collected water upon detection of the
collected water temperature being at or below a threshold value. In
an embodiment the collected water is stored in the evaporative
liquid reservoir. In an embodiment the apparatus further includes a
dry passage water nozzle configured to expel accumulated water from
dehumidification of the first volume of air.
[0008] According to another aspect of the present disclosure, a
method of conserving water temperature for cooling air in an
indirect evaporative cooler includes: having a heat exchanger
comprising a dry passage and a wet passage, the dry passage in
thermodynamic communication with the wet passage and separated from
the wet passage by a substantially liquid-impermeable membrane
having a hydrophobic surface facing the dry passage and a
hydrophilic surface facing the wet passage, the dry passage
comprising an intake portion, an outlet portion, and a loop
portion; moving a first volume of air through the dry passage while
dispensing an evaporative liquid having a first temperature onto
the hydrophilic surface to cool and dehumidify the first volume of
air; collecting water condensed from the dehumidification of the
first volume of air; and dispensing the collected water onto the
hydrophilic surface to cool and dehumidify a second volume of
air.
[0009] In an embodiment of the method collecting water includes
storing in an external reservoir operable to also store the
evaporative liquid. In an embodiment collecting water includes
storing in an internal reservoir disposed within a housing that
contains the heat exchanger. In an embodiment the dispensing
includes directing the collected water via a supply pipe to a wet
passage nozzle, the supply pipe having an associated pressure valve
for maintaining a dispensing rate. In an embodiment the dispensing
is controlled to occur when the collected water has a second
temperature that is lower than the first temperature.
[0010] According to another aspect of the present disclosure, a
system for conserving water temperature for cooling air includes:
an evaporative liquid reservoir comprising a pressure valve and a
channel adapted to transport evaporative liquid; a heat exchanger
comprising: a dry passage and a wet passage, the dry passage in
thermodynamic communication with the wet passage and separated from
the wet passage by a substantially liquid-impermeable membrane
having a hydrophobic surface facing the dry passage and a
hydrophilic surface facing the wet passage, the dry passage
comprising an intake portion, an outlet portion, and a loop
portion; a nozzle coupled with the channel and configured to wet
the wet passage for evaporative cooling of the substantially
liquid-impermeable membrane; a mixing valve disposed in the dry
passage and configured to selectively pass intake air from the
intake portion, recirculation air from the loop portion, or a
combination thereof; a first fan disposed downstream of the mixing
valve and adapted to move a first volume of air into and through
the loop portion; and a diverting valve disposed in the dry passage
and configured to selectively pass outlet air to the outlet
portion, recirculation air to the mixing valve, or a combination
thereof; and a controller adapted to operate the mixing valve, the
first fan, the diverting valve, and a combination thereof, to move
a first volume of air through the dry passage while dispensing
evaporative liquid having a first temperature through the nozzle
onto the hydrophilic surface to cool and dehumidify the first
volume of air, and to dispense collected water condensed from the
dehumidification of the first volume of air onto the hydrophilic
surface to cool and dehumidify a second volume of air.
[0011] In an embodiment of the system the collected water is stored
in an internal liquid reservoir disposed within a housing that
contains the heat exchanger and coupled with the nozzle. In an
embodiment the controller is adapted to increase pressure in the
internal liquid reservoir to dispense the collected water upon
detection of the collected water temperature being at or below a
threshold value. In an embodiment the collected water is stored in
the evaporative liquid reservoir. In an embodiment the system
further includes a dry passage water nozzle configured to expel
accumulated water from dehumidification of the first volume of
air.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Embodiments of the present disclosure are illustrated by way
of example, and not by way of limitation, in the figures of the
accompanying drawings and in which like reference numerals refer to
similar elements.
[0013] FIG. 1 is an illustration depicting an exemplary indirect
cooling apparatus, according to an embodiment of the present
disclosure.
[0014] FIG. 2 is a cross-section of a portion of an exemplary
indirect cooling apparatus including a dry passage and a wet
passage, according to an embodiment of the present disclosure.
[0015] FIG. 3 depicts an exemplary cooling and dehumidifying
sequence via a psychrometric chart, according to an embodiment of
the present disclosure.
[0016] FIG. 4 is a block diagram depicting an exemplary air
conditioning application according to an embodiment of the present
disclosure.
[0017] FIG. 5 illustrates an exemplary process of conditioning air
in an indirect evaporative air conditioner, according to an
embodiment of the present disclosure.
[0018] FIG. 6 illustrates a block diagram of an exemplary air
conditioning device configured to implement an air conditioning
application according to some embodiments of the present
disclosure.
DETAILED DESCRIPTION OF THE INVENTION
[0019] Reference will now be made in detail to the various
embodiments of the present disclosure, examples of which are
illustrated in the accompanying drawings. While described in
conjunction with these embodiments, it will be understood that they
are not intended to limit the disclosure to these embodiments. On
the contrary, the disclosure is intended to cover alternatives,
modifications and equivalents, which may be included within the
spirit and scope of the disclosure as defined by the appended
claims. Furthermore, in the following detailed description of the
present disclosure, numerous specific details are set forth in
order to provide a thorough understanding of the present
disclosure. However, it will be understood that the present
disclosure may be practiced without these specific details. In
other instances, well-known methods, procedures, components, and
circuits have not been described in detail so as not to
unnecessarily obscure aspects of the present disclosure.
[0020] Some portions of the detailed description that follows are
presented in terms of procedures, steps, logic blocks, processing,
and other symbolic representations of operations on data bits that
can be performed on computer memory. These descriptions and
representations are the means used by those skilled in the data
processing arts to most effectively convey the substance of their
work to others skilled in the art. A procedure, computer generated
step, logic block, process, etc., is here, and generally, conceived
to be a self-consistent sequence of steps or instructions leading
to a desired result. The steps are those requiring physical
manipulations of physical quantities. Usually, though not
necessarily, these quantities take the form of electrical or
magnetic signals capable of being stored, transferred, combined,
compared, and otherwise manipulated in a computer system. It has
proven convenient at times, principally for reasons of common
usage, to refer to these signals as bits, values, elements,
symbols, characters, terms, numbers, or the like.
[0021] It should be borne in mind, however, that all of these and
similar terms are to be associated with the appropriate physical
quantities and are merely convenient labels applied to these
quantities. Unless specifically stated otherwise as apparent from
the following discussions, it is appreciated that throughout the
present claimed subject matter, discussions utilizing terms such as
"storing," "creating," "protecting," "receiving," "encrypting,"
"decrypting," "destroying," or the like, refer to the action and
processes of a computer system or integrated circuit, or similar
electronic computing device, including an embedded system, that
manipulates and transforms data represented as physical
(electronic) quantities within the computer system's registers and
memories into other data similarly represented as physical
quantities within the computer system memories or registers or
other such information storage, transmission or display
devices.
Dynamic Cycling and Incremental Dehumidification of Air in Indirect
Evaporator
[0022] In one embodiment of the present disclosure, an indirect
evaporative cooler apparatus is able to cycle air dynamically
through one or more dry passages of the indirect evaporative
cooler, for cooling and/or dehumidification of a volume of air.
Indirect evaporative cooling describes cooling in which an
airstream is first cooled by adiabatic saturation, and then used to
cool a separate, non-mixing airstream across a heat-transfer
partition (e.g., an airstream of a wet passage is in thermodynamic
communication with an airstream of a dry passage). The latter
airstream is said to be sensibly cooled; that is, cooled without
altering its absolute moisture content.
[0023] Referring now to FIG. 1, an exemplary indirect evaporative
cooling apparatus is depicted according to an embodiment of the
present disclosure. Indirect evaporative cooling apparatus 100
includes a controller 103 operable to control valves, fans, pumps,
and other components of indirect evaporative cooling apparatus 100
according to embodiments of the apparatus as described herein.
Indirect evaporative cooling apparatus 100 includes an intake
portion 105, a mixing valve 110, a loop portion 115, an outlet
portion 120, and a diverting valve 125. Indirect cooling apparatus
100 includes one or more dry passages, and one or more wet
passages. Dry passages and wet passages are thermodynamically
coupled, such that a volume of air transported through a dry
passage can be cooled, indirectly, via evaporative cooling
occurring in a wet passage. The volume of air can be transported
into and through the dry passage by a fan 135, which according to
an embodiment is disposed such that the mixing valve 110 is between
the fan 135 and the intake portion 105 and a return portion of loop
portion 115.
[0024] According to an embodiment, one or more nozzles 130 (e.g., a
layer nozzle) are disposed above the one or more wet passages, the
nozzles 130 configured to dispense water (or other suitable liquid)
for wetting a surface of wet passage for evaporative cooling.
According to an embodiment one or more dry passage nozzles 140 are
disposed within the one or more dry passages, and are configured to
expel water from within the dry passage. The water may accumulate,
for example, via condensation from a dehumidifying function of the
indirect evaporative cooling apparatus 100. The nozzle 140 can be
disposed to expel the condensed water onto a surface of a wet
passage located below the nozzle 140. Alternatively, the nozzle 140
can be disposed to expel the condensed water to be collected in a
water reservoir, for example an external reservoir 145 and/or an
internal water reservoir 165. While not shown, indirect evaporative
cooling apparatus 100 can include one or more barometers,
hygrometers (humidity sensors), and thermometers, that are operable
to measure their respective environmental conditions in the dry
and/or wet passages, and to report corresponding values to
controller 103.
[0025] According to an embodiment, an external reservoir 145
supplies an evaporative liquid to nozzles 130 for wetting of wet
passages of the indirect evaporative cooling apparatus 100. The
evaporative liquid can be water, for example, although other
liquids suitable for evaporative cooling in wet passages of the
indirect evaporative apparatus 100 can be used, as is appreciated
by those of skill in the art. The external reservoir 145 can have
an associated pressure valve 150, along with a supply pipe 155 and
a supply pump 160. According to embodiments of the present
disclosure, a supply pressure of nozzles 130 is set by pressure
valve 150, controlled by controller 103. According to an
embodiment, indirect evaporative cooling apparatus 100 includes a
manifold 180 arranged to house one or more nozzles 130 and to
dispense evaporative liquid over the one or more wet passages.
According to an embodiment, an optional internal water reservoir
165 is located to accumulate from nozzles 130 and/or condensed
water from nozzles 140. The internal water reservoir can include an
associated supply pipe 170 and pump 175 to provide accumulated
water for dispensing from nozzles 130 (e.g., via optional manifold
180).
[0026] As depicted in FIG. 1, the dry passage can be arranged in a
serpentine arrangement such that a volume of air is transported
from the intake portion 105 and follows a number of turns before
arriving at the diverting valve 125. The wet passage can follow a
substantially similar course as the dry passage, such that
thermodynamic communication is maintained between the dry and wet
passage. According to an embodiment the serpentine arrangement is
descending, that is, with the intake portion 105 being positioned
higher (e.g., at a greater gravitational or pressure potential)
than the outlet portion 120. The diverting valve 125 is disposed
upstream of the loop portion 115 and the outlet portion 120 with
regard to the direction of air travel, and is operable to pass the
volume of air through the outlet portion 120, the loop portion 115,
a combination thereof, or to close both pathways 120 and 115. The
diverting valve 125 is under controller 103 control. Optionally, a
fan 185 can be included disposed upstream of diverting valve 125,
fan 185 under control of controller 103 and operable to assist the
movement of the volume of air through the dry passage. For example,
optional fan 185 can assist in moving the volume of air in
recirculation toward mixing valve 110, and/or toward outlet portion
120.
[0027] According to some embodiments of the present disclosure,
some portions of the dry passage include one or more elements to
induce a pressure differential within the dry passage (e.g., air
traps 190 or a heat exchange coil, not shown). Additionally or
alternatively, indirect evaporative cooling apparatus 100 can
include an exhaust pipe (not shown) having an associated exhaust
valve (not shown) and exhaust fan (not shown), disposed on an
enclosure of apparatus 100 and operable to develop a negative
pressure differential in the one or more wet passages relative to
ambient pressure. These features, as well as other characteristics
of the indirect evaporative cooling apparatus of the present
disclosure, can be better appreciated by a description of the
internal components and functions of the indirect evaporative
cooling apparatus herein.
[0028] Referring now to FIG. 2, a cross section A-A of FIG. 1 is
depicted according to an exemplary embodiment of the indirect
evaporative cooling apparatus 100. FIG. 2 depicts a number N of
parallel dry passages 203. As shown, dry passages 203 have a
hexagonal cross-section 205, although it is appreciated by those of
skill in the art that other cross-section configurations (circular,
oval, square, etc.) are possible. In between portions of dry
passages 203 are wet passages 210. An expanded view of a portion of
dry passage 203 depicts nozzle 230 configured to wet the wet
passages 210, and a nozzle 240 configured to expel any accumulated
water from dry passages 203. Separating dry passages 203 and wet
passages 210 is a substantially liquid impermeable membrane 215,
providing thermodynamic communication between dry passages 203 and
wet passages 210 while preventing fluid to flow freely there
between. According to an embodiment of the present disclosure
membrane 215 includes a hydrophilic surface oriented toward wet
passages 210, and a hydrophobic surface oriented toward dry
passages 203. In this manner wet passages 210, when wet (e.g., from
nozzle 130) will preferentially retain liquid to be used for
evaporative cooling. Meanwhile, surfaces of dry passages 203 repel
any water introduced, for example via condensation from
dehumidification of a volume of air passing through dry passages
203, easing the removal of condensed water from dry passages 203
(e.g., via nozzles 140). According to an embodiment of the present
disclosure the indirect evaporative cooling apparatus 100 includes
an internal water reservoir 265, which is configured to receive
water from nozzles 230 and/or nozzles 240. The collected water can
be recycled, that is, used again to dispense water over wet
passages 210 via nozzles 230 for evaporative cooling of membrane
215 (and induced cooling of a volume of air traveling through dry
passages 203.
[0029] Referring now to FIG. 3, an exemplary cooling and
dehumidifying sequence for a volume of air moving through a dry
passage of the indirect evaporative cooling apparatus is depicted
via psychrometric graph, according to an embodiment of the present
disclosure. As seen in FIG. 3 at location A there is relatively hot
and humid air, corresponding to an initial state of a volume of air
that is directed to move through the dry passage (e.g., intake air
through intake portion 105 of apparatus 100). As the volume of air
moves through the dry passage and is cooled via indirect
evaporative cooling (e.g., evaporative cooling in thermodynamically
coupled wet passage), the volume of air is reduced in temperature
without gaining moisture. That is, the specific humidity of the
volume of air remains constant, while the relative humidity
increases to substantially the dew point (due to the decrease in
temperature of the volume of air). This is represented by the
transition between locations A and B on the psychrometric graph of
FIG. 3. The transition from locations A and B on the psychrometric
graph can correspond to a number of circuits of the volume of air
through the loop portion of a dry passage, where each circuit leads
to further cooling of the volume of air.
[0030] Once the volume of air substantially reaches its dew point
(based on the specific humidity of the air upon intake at intake
portion 105), further cooling of the now-saturated air (100%
relative humidity) causes condensation of water from the volume of
air. This is represented by the transition from locations B and C
on the psychrometric graph. At location C the volume of air has
been both cooled from its initial temperature at location A, and
dehumidified from its initial specific humidity (locations A and
B). The transition from locations B and C on the psychrometric
graph can correspond to a further number of circuits of the volume
of air through the loop portion of a dry passage, where each
circuit leads to further cooling and dehumidification of the volume
of air. This may be termed incremental cooling and/or
dehumidification. By incremental it is meant incorporating the
dehumidification processes and the cooling process, e.g., each
cooling cycle the volume of air is dehumidified as well as cooled.
In this manner the volume of air, as it circulates in the dry
passage of the indirect evaporative cooling apparatus, is cooled
and dehumidified bit by bit, each cycle (e.g., circuit of air
through a dry passage) resetting the starting conditions of the
volume of air. According to an embodiment of the present
disclosure, condensed water is removed from the dry passage during
this incremental cooling and dehumidification process, as described
herein.
[0031] Referring now to FIG. 4 a block diagram depicts an exemplary
air conditioning application according to an embodiment of the
present disclosure. Air conditioning application 400 can be
embodied on a memory and executed by a processor of a computing
device, for example controller 103. Air conditioning application
400 includes an inputs module 405, a controls module 410, and an
output module 420. Inputs module 405 is configured to receive data
regarding environmental conditions of the indirect evaporative
cooling apparatus, such as a temperature of a dry passage and/or a
wet passage, a humidity of a dry passage, and a pressure of a dry
passage and/or a wet passage. Data can be generated from
appropriate sensors (e.g., thermometers, hygrometers, barometers),
which according to an embodiment can be located at various
locations throughout the indirect evaporative cooling
apparatus.
[0032] Controls module 410 is configured to send control signals to
components of indirect evaporative cooling apparatus determined,
from environmental conditions of the indirect evaporative cooling
apparatus. Components of the indirect evaporative cooling apparatus
that are controlled by controls module 410 include mixing valve 110
and intake fan 135, diverting valve 125, optional fan 185, and
optional exhaust valve and fan. Controls module 410 can also
control operation of reservoir valve 150, pump 160, and optional
internal reservoir pump 175, along with any other electromechanical
components included in the indirect evaporative cooling apparatus
of the present disclosure.
[0033] Output module 420 delivers control signals to the components
of the indirect evaporative cooling apparatus according to the
operations determined by controls module 410. Exemplary operations
include: single cycle operation; dynamic cycle operation; high
pressure operation; low pressure operation; and water
operation.
[0034] In single cycle operation a volume of air is controlled to
move once through the dry passage(s) of the indirect evaporative
cooling apparatus, which may be accomplished by opening mixing
valve 110 to air from intake portion 105, and diverting valve 125
to outlet portion 120 only--that is, not mixing the volume of air
through loop portion 115. Fan 135 (and/or optional fan 185) can be
operated to enhance the movement of the volume of air through the
dry passage(s).
[0035] In dynamic cycle operation initially mixing valve 110 is
opened to air from intake portion 105, and then mixing valve 110 is
closed to intake portion 105 in order to introduce a first volume
of air to dry passage(s). Movement of the first volume of air
through the dry passage(s) can be enhanced by operation of fan 135
and/or optional fan 185. Diverting valve 125 is controlled to close
air movement to outlet portion 120, and to re-circulate the first
volume of air through loop portion 115. In this manner the first
volume of air can be made to circulate through the dry passage(s) a
number of times, and to be continuously cooled via indirect
evaporative cooling. According to embodiments of the present
disclosure, dynamic cycling of a volume of air through the indirect
evaporative cooling apparatus is used to dehumidify the volume of
air, as well as to cool, as is described further herein below.
[0036] In high pressure operation mixing valve 110 is opened to air
from intake portion 105 and diverting valve 125 is closed to outlet
portion 120--that is, the volume is air is not expelled from the
indirect evaporative cooling apparatus. Fan 135 (and/or optional
fan 185) can be operated to enhance the movement of the volume of
air into the dry passage(s). In an embodiment, diverting valve 125
is closed so that the volume of air is not diverted to loop portion
115. In an embodiment, diverting valve 125 is open to loop portion
115 (but closed to outlet portion 120), such that air is
re-circulated through the dry passage(s) (e.g., for pressurization
and cooling of the volume of air in the dry passage).
[0037] In low pressure operation the wet passage(s) of the indirect
evaporative cooling apparatus develop of a lower pressure, with
respect to the ambient pressure and/or the pressure in dry
passage(s). A lower pressure in the wet passage(s) encourages
evaporation of liquid at surfaces of the wet passage(s), enhancing
the indirect cooling effect. According to an embodiment of the
present disclosure, the indirect evaporative cooling apparatus
includes an exhaust fan and valve in an enclosure. The exhaust fan
and valve can be operated by controller 103 to force air out of wet
passage(s) of the indirect evaporative cooling apparatus, and to
thereby develop a low pressure in the wet passage(s) (e.g., a
negative pressure with respect to ambient and/or dry passage
pressure).
[0038] In water operation the components of the external reservoir
145 and of optional internal water reservoir 165 are controlled to
store and distribute liquid for evaporative cooling of wet passages
of the indirect evaporative cooling apparatus. Output module 420
can signal reservoir valve 150 to open or close, and pump 160 to
operate to move liquid to external reservoir 145. In some
embodiments pump 160 is operated to pressurize external reservoir
145, in order to increase a water pressure and/or a rate at which
wet passage water nozzles dispense water. In an embodiment output
module 420 signals optional internal reservoir pump 175 to close in
order to retain accumulated water. In an embodiment output module
420 signals optional internal reservoir pump 175 to pump water up
to be dispensed over wet passages, for example via optional
manifold 180. In an embodiment valve 150 is signaled to open in
order to return accumulated water in internal reservoir 165 to
external reservoir 145. Valve 150 operation can be determined from
one or more of: dry passage and/or wet passage temperature;
temperature of water in internal reservoir 165 and/or external
reservoir 145; a water level of internal reservoir 165 and/or
external reservoir 145.
Indirect Evaporation via Pressure Differentials
[0039] According to some embodiments of the present disclosure, for
air stream detected to be substantially on its dew point,
dehumidification of the air stream can be accomplished via pressure
differentials within regions of the indirect evaporative cooling
apparatus 100. According to some embodiments of the present
disclosure, some portions of the dry passage include one or more
elements to induce a pressure differential within the dry passage,
for example air traps 190 and/or a heat exchange coil (not shown).
Air traps 190 are disposed on one or more surfaces of the dry
passage(s), and function to cause regions of increased pressure
within an airstream moving through the dry passage. A higher
pressure within a saturated, or nearly saturated, airstream is able
to cause condensation of water from the airstream (e.g.,
dehumidification). Additionally or alternatively, an indirect
evaporative cooling apparatus of the present disclosure can include
an exhaust pipe (not shown) having an associated exhaust valve (not
shown) and exhaust fan (not shown), disposed on an enclosure of
apparatus and operable to develop a negative pressure differential
in the one or more wet passages relative to ambient pressure. A
reduced pressure in a wet passage of the indirect evaporative
cooling apparatus is able to increase an evaporation of a liquid
wetting a surface of the wet passage, and thereby to increase
cooling of the airstream in the adjacent dry passage.
[0040] FIG. 5 illustrates an exemplary process 500 of conditioning
air in an indirect evaporative air conditioner, according to an
embodiment of the present disclosure. Step 501 includes circulating
a first volume of air through a loop portion of a dry passage of an
indirect evaporative air conditioner (e.g., apparatus 100).
According to an embodiment, the dry passage is in thermodynamic
communication with a wet passage that is configured to receive and
to evaporate a liquid. The dry passage and the wet passage together
form a heat exchanger (e.g., dry passage 203, wet passage 210,
membrane 215 of FIG. 2).
[0041] Step 503 includes determining a relative humidity of the
first volume of air. The relative humidity can be determined based
on a barometric pressure and/or a temperature in the dry passage.
According to an embodiment, the indirect evaporative cooling
apparatus can determine the barometric pressure and/or the
temperature from an included one or more barometers, hygrometers
(humidity sensors), and thermometers, that are operable to measure
their respective environmental conditions in the dry and/or wet
passages, and to report corresponding values to a controller (e.g.,
controller 103 of FIG. 1).
[0042] Step 505 includes selectively generating a pressure
differential in the heat exchanger upon the first volume of air
determined to be substantially at its dew point, by increasing
barometric pressure in the dry passage, decreasing barometric
pressure in the wet passage, or a combination thereof, sufficient
to condense water from the first volume of air. The selective
pressure differential generation can be accomplished using a
controller 103 running an air conditioning application 400, for
example by performing a high pressure operation, a low pressure
operation, or a combination of these as described herein.
Water Conservation in Indirect Evaporator
[0043] According to an embodiment of the present disclosure water
condensed from a dehumidification process of a volume of air moving
through an indirect evaporative cooler can be captured and/or
recycled for use in subsequent wetting of one or more wet passages
of the indirect evaporative cooler. In this manner water is
conserved from the incoming air stream, which, as it cools in a dry
passage, approaches its dew point and then commences condensation
of water contained in the air stream. This condensed water can
gather on a surface of a dry passage (e.g., hydrophobic surface of
a dry passage 203), and can be expelled from the dry passage. One
means of expelling condensed water is by a water nozzle (e.g.,
water nozzle 240). The removal of condensed water from a dry
passage can be aided by increasing the pressure within the dry
passage, with respect to ambient pressure (and/or with respect to
the wet passage).
[0044] According to an embodiment of the present disclosure an
indirect evaporative cooling apparatus (e.g., apparatus 100)
includes an internal water reservoir (e.g., reservoir 265), which
is configured to receive water from wet passage nozzles and/or dry
passage nozzles. Alternatively or additionally, captured water can
be returned to an external liquid reservoir (e.g., reservoir 145).
The collected water can be recycled, that is, used again to
dispense water over wet passages 210 via nozzles 230 for
evaporative cooling of membrane 215 (and induced cooling of a
volume of air traveling through dry passages 203).
Exemplary Computing Device
[0045] FIG. 6 illustrates a block diagram of an exemplary air
conditioning device 600 configured to implement an air conditioning
application 400 according to some embodiments. The air conditioning
device 600 is able to be one or more of the indirect evaporative
cooling apparatuses 100, including controller 103 and/or other
computing devices that are able to acquire, store, compute,
communicate and/or display information such as images and videos.
In general, a hardware structure suitable for implementing the air
conditioning device 600 includes a network interface 602, a memory
604, a processor 606, I/O device(s) 608, a bus 610 and a storage
device 612. Alternatively, one or more of the illustrated
components are able to be removed or substituted for other
components well known in the art. The choice of processor is not
critical as long as a suitable processor with sufficient speed is
chosen. The memory 604 is able to be any conventional computer
memory known in the art. The storage device 612 is able to include
a hard drive, CDROM, CDRW, DVD, DVDRW, flash memory card or any
other storage device. The air conditioning device 600 is able to
include one or more network interfaces 602. An example of a network
interface includes a network card connected to an Ethernet or other
type of LAN. The I/O device(s) 608 are able to include one or more
of the following: keyboard, mouse, monitor, display, printer,
modem, touchscreen, button interface and other devices. As
described above, the air conditioning application 630 is to be
stored in the storage device 612 and memory 604 and processed as
applications are typically processed. Greater or fewer components
than shown in FIG. 6 are able to be included in the air
conditioning device 600. In some embodiments, air conditioning
hardware 620 is included. Although the air conditioning device 600
in FIG. 6 includes the air conditioning application 630 and air
conditioning hardware 620, the air conditioning functions described
herein are able to be implemented on the air conditioning device
600 via hardware, firmware, software separately, or any combination
thereof.
[0046] The foregoing description, for purpose of explanation, has
been described with reference to specific embodiments. However, the
illustrative discussions above are not intended to be exhaustive or
to limit the invention to the precise forms disclosed. Many
modifications and variations are possible in view of the above
teachings. The embodiments were chosen and described in order to
best explain the principles of the invention and its practical
applications, to thereby enable others skilled in the art to best
utilize the invention and various embodiments with various
modifications as may be suited to the particular use
contemplated.
[0047] Embodiments according to the invention are thus described.
While the present disclosure has been described in particular
embodiments, it should be appreciated that the invention should not
be construed as limited by such embodiments, but rather construed
according to the below claims.
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