U.S. patent application number 14/167072 was filed with the patent office on 2014-05-29 for method of wetting evaporative cooler media through a fabric distribution layer.
This patent application is currently assigned to BHA ALTAIR, LLC. The applicant listed for this patent is Vishal Bansal, Peter John Duncan Smith. Invention is credited to Vishal Bansal, Peter John Duncan Smith.
Application Number | 20140144171 14/167072 |
Document ID | / |
Family ID | 50772074 |
Filed Date | 2014-05-29 |
United States Patent
Application |
20140144171 |
Kind Code |
A1 |
Smith; Peter John Duncan ;
et al. |
May 29, 2014 |
Method of Wetting Evaporative Cooler Media Through a Fabric
Distribution Layer
Abstract
An evaporative cooler, and associated method, that includes an
evaporative pad including a liquid coolant-receiving surface at
which a liquid coolant distributed to the evaporative pad is
received and thereafter passes into the evaporative pad. The
evaporative cooler also includes a liquid coolant distribution
trough that includes an upper portion configured to hold liquid
coolant and a lower portion contiguous with the upper portion. The
lower portion includes an opening and a fabric distribution layer
in place over the opening through which the liquid coolant held in
the upper portion of the liquid coolant distribution trough passes
and is distributed to the liquid coolant-receiving surface of the
evaporative pad.
Inventors: |
Smith; Peter John Duncan;
(Basingstoke, GB) ; Bansal; Vishal; (Overland
Park, KS) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Smith; Peter John Duncan
Bansal; Vishal |
Basingstoke
Overland Park |
KS |
GB
US |
|
|
Assignee: |
BHA ALTAIR, LLC
Franklin
TN
|
Family ID: |
50772074 |
Appl. No.: |
14/167072 |
Filed: |
January 29, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13173072 |
Jun 30, 2011 |
|
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14167072 |
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Current U.S.
Class: |
62/304 |
Current CPC
Class: |
F24F 5/0035 20130101;
F28C 3/08 20130101; F24F 1/0007 20130101; F28C 1/04 20130101; F24F
6/043 20130101; F28D 2021/0026 20130101; Y02B 30/54 20130101; Y02B
30/545 20130101; F28F 25/04 20130101 |
Class at
Publication: |
62/304 |
International
Class: |
F28C 3/08 20060101
F28C003/08 |
Claims
1. An evaporative cooler including: an evaporative pad, including a
liquid coolant-receiving surface at which a liquid coolant
distributed to the evaporative pad is received and thereafter
passes into the evaporative pad; a liquid coolant delivery member
located above the evaporative pad for delivering the liquid coolant
to a location above the evaporative pad; and a liquid coolant
distribution trough for receiving the liquid coolant that is
delivered to the location above the evaporative pad and for
distributing the liquid coolant to the liquid coolant-receiving
surface of the evaporative pad, the liquid coolant distribution
trough including an upper portion for receiving the liquid coolant
and temporarily holding the liquid coolant and a lower portion
contiguous with the upper portion, the lower portion including an
opening directed to the liquid coolant-receiving surface of the
evaporative pad and sized congruently with a size of the liquid
coolant-receiving surface of the evaporative pad, and the lower
portion including a fabric distribution layer in place over the
opening through which the liquid coolant temporarily held in the
upper portion of the liquid coolant distribution trough passes and
is distributed to the liquid coolant-receiving surface of the
evaporative pad, the liquid coolant temporarily held in the upper
portion of the liquid coolant distribution trough wetting an
entirety of the fabric distribution layer and the liquid coolant
passing through the fabric distribution layer wetting an entirety
of the liquid coolant-receiving surface of the evaporative pad.
2. The evaporative cooler of claim 1, wherein a perimeter of an
outer boundary of the evaporative pad, a perimeter of the liquid
coolant-receiving surface and a perimeter of the opening in the
lower portion of the liquid coolant distribution trough have a
shared boundary.
3. The evaporative cooler of claim 1, wherein the upper portion of
the liquid coolant distribution trough is configured to maintain
the temporarily held liquid coolant at a selected depth in the
upper portion of the liquid distribution trough above the fabric
distribution layer, and the fabric distribution layer has a
permeability characteristic such that the liquid coolant is
distributed to the liquid coolant-receiving surface of the
evaporative pad through the fabric distribution layer to cause the
evaporative pad to be wetted by the liquid coolant flowing from the
liquid coolant-receiving surface of the evaporator pad towards the
liquid coolant-exiting surface of the evaporator pad but
insufficient to cause liquid coolant to exit the liquid
coolant-exiting surface of the evaporative pad.
4. The evaporative cooler of claim 1, wherein the fabric
distribution layer includes a flat upper surface to allow
horizontal movement of the temporarily held liquid coolant in the
upper portion of the trough.
5. The evaporative cooler of claim 1, wherein the fabric
distribution layer is porous and has pores.
6. The evaporative cooler of claim 5, wherein the pores are of
uniform size.
7. The evaporative cooler of claim 5, wherein the pores are of a
size sufficient provide a back pressure for enabling the liquid
coolant to be temporarily held within the upper portion of the
trough.
8. The evaporative cooler of claim 7, wherein the pores are of a
size to provide 1.5 to 2.0 gallons/min/ft2 of liquid coolant flow
with less than 2 inches of liquid coolant head.
9. The evaporative cooler of claim 5, wherein the fabric
distribution layer has at least one of a hydrophilic treatment and
a wicking treatment.
10. The evaporative cooler of claim 1, wherein the fabric
distribution layer includes a spunbond fabric.
11. The evaporative cooler of claim 10, wherein the spunbond fabric
includes at least one of polypropylene, polyester, polyethylene,
and Nylon.
12. The evaporative cooler of claim 1, wherein the fabric
distribution layer includes a melt blown fabric.
13. The evaporative cooler of claim 12, wherein the melt blown
fabric includes at least one of polypropylene, PBT, PET, Nylon and
polyethylene.
14. The evaporative cooler of claim 1, wherein the fabric
distribution layer includes a needlepunched fabric.
15. The evaporative cooler of claim 14, wherein the needlepunched
fabric includes at least one of polypropylene, polyester, PVDF and
PTFE.
16. The evaporative cooler of claim 1, wherein the fabric
distribution layer includes a hydroentangled fabric.
17. The evaporative cooler of claim 16, wherein the hydroentangled
fabric includes at least one of polypropylene, polyester, PVDF and
PTFE.
18. The evaporative cooler of claim 1, wherein the fabric
distribution layer includes an airlaid calendared fabric.
19. The evaporative cooler of claim 1, wherein the fabric
distribution layer includes a membrane.
20. The evaporative cooler of claim 1, wherein the fabric
distribution layer includes multiple layers, with at least two of
the multiple layers having differing materials.
Description
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS
[0001] This patent application is a continuation-in-part of U.S.
patent application Ser. No. 13/173,072, filed Jun. 30, 2011, the
entire teachings and disclosure of which are incorporated herein by
reference thereto.
FIELD OF THE INVENTION
[0002] The present invention relates generally to a method and
apparatus concerning the operation of evaporative cooling systems
and, in particular, to a method and apparatus concerning the
effective wetting by a liquid coolant of an evaporative pad of an
evaporative cooling system that cools air supplied to a gas turbine
system.
DISCUSSION OF THE PRIOR ART
[0003] Evaporative cooling systems, or evaporative coolers as such
systems are typically referred to, are employed in various ways in
residential, commercial and industrial contexts. In one example,
the evaporative coolers cool air that is directed through the
evaporative coolers. The evaporative coolers cool the air through
the evaporation of a liquid coolant, typically water, which is
brought into contact with the air at the evaporative coolers.
[0004] Typically, an evaporative cooler includes an evaporative pad
at which the air directed to the evaporative cooler is cooled. A
liquid coolant, such as water for example, is caused to flow
through the evaporative pad and air is brought into contact with
the coolant at the pad, usually by means of a fan, blower or
turbine drawing or forcing the air through the pad. The evaporative
pad typically is constructed of a material that has a large surface
area over which the coolant is dispersed so that the coolant
assumes a large surface area at the evaporative pad, thereby
facilitating the evaporation of the coolant at the pad. Heat
transfer takes place between the air and the dispersed coolant, as
the air comes into contact with the coolant at the evaporative pad,
and the coolant thereby evaporated, causing the air to cool and the
density of the air to increase. Coolant is continuously delivered
to the evaporative pad to replace the coolant that evaporates.
[0005] Evaporative coolers are known to be employed for the purpose
of cooling the living spaces of residential structures and the
working environments of commercial and industrial buildings for
thermal comfort for example. In addition, evaporative coolers are
known to be applied in industrial processes in which a supply of
cooler and denser air can be used to advantage. For example, an
evaporative cooler can be employed in conjunction with a gas
turbine system wherein the cooled air from the evaporative cooler
is compressed and the compressed air mixed with a fuel such as
natural gas for example. The mixture of air and fuel is combusted
and the resulting expanding gases are directed to a turbine so as
to drive the turbine that, in turn, drives an electrical generator
for producing electrical power for example. The cooled air, because
of its increased density, provides a higher mass flow rate and
pressure ratio at the gas turbine equipment, resulting in an
increase in turbine output and efficiency.
[0006] The foregoing benefit, however, may not be fully realized in
those instances in which the evaporative pad is not completely
wetted by the coolant so that the air passing through the pad is
cooled to a lesser extent than would be the case in which the pad
is entirely wetted by the coolant. Specifically, in previous
designs, conduit pipes that drip or spray coolant provide uneven
distribution of coolant. Additionally, the areas of the evaporative
pad that are not wetted by the coolant can result in the
establishment of temperatures in the air that passes through these
non-wetted areas that are warmer than the temperatures in the air
that has come into contact with the coolant in areas of the
evaporative pad that have been wetted by the liquid coolant. These
temperature differences in the respective air masses that are then
directed to the turbine compressor can cause air turbulence that
can result in damage to the turbine equipment. Even in the absence
such damage, the vibration of the turbine blades can result in the
deteriorated performance of the turbine equipment.
BRIEF DESCRIPTION OF THE INVENTION
[0007] The following sets forth a simplified summary of examples of
the present invention for the purpose of providing a basic
understanding of selected aspects of the invention. The summary
does not constitute an extensive overview of all the aspects or
embodiments of the invention. Neither is the summary intended to
identify critical aspects or delineate the scope of the invention.
The sole purpose of the summary is to present selected aspects of
the invention in a simplified form as an introduction to the more
detailed description of the embodiments of the invention that
follows the summary.
[0008] In accordance with one aspect, the present invention
provides an evaporative cooler that includes an evaporative pad.
The evaporative pad includes a liquid coolant-receiving surface at
which a liquid coolant distributed to the evaporative pad is
received and thereafter passes into the evaporative pad. The
evaporative cooler includes a liquid coolant delivery member
located above the evaporative pad for delivering the liquid coolant
to a location above the evaporative pad. The evaporative cooler
includes a liquid coolant distribution trough for receiving the
liquid coolant that is delivered to the location above the
evaporative pad and for distributing the liquid coolant to the
liquid coolant-receiving surface of the evaporative pad. The liquid
coolant distribution trough includes an upper portion for receiving
the liquid coolant and temporarily holding the liquid coolant and a
lower portion contiguous with the upper portion. The lower portion
includes an opening directed to the liquid coolant-receiving
surface of the evaporative pad and sized congruently with a size of
the liquid coolant-receiving surface of the evaporative pad. The
lower portion includes a fabric distribution layerbed in place over
the opening through which the liquid coolant temporarily held in
the upper portion of the liquid coolant distribution trough passes
and is distributed to the liquid coolant-receiving surface of the
evaporative pad. The liquid coolant temporarily held in the upper
portion of the liquid coolant distribution trough wetting an
entirety of the fabric distribution layer and the liquid coolant
passing through the fabric distribution layer wetting an entirety
of the liquid coolant-receiving surface of the evaporative pad.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The foregoing and other aspects of the present invention
will be apparent to those skilled in the art to which the present
invention relates from the detailed descriptions of examples of
aspects and embodiments of the invention that follow with reference
to the accompanying drawings, wherein the same reference numerals
are used in the several figures to refer to the same parts or
elements and in which:
[0010] FIG. 1 is a schematic side elevational view of an example of
an evaporative cooling system, or evaporative cooler, incorporated
in an air-conditioning system that supplies cooled air to a gas
turbine system;
[0011] FIG. 2 is a schematic perspective view of an example of a
liquid coolant distribution trough for distributing liquid coolant
to an evaporative pad of an evaporative cooler such as the
evaporative cooler referred to with respect to FIG. 1;
[0012] FIG. 3 is a schematic cross-sectional view of the liquid
coolant distribution trough of FIG. 2, with the liquid coolant
shown within the trough above a fabric distribution layer;
[0013] FIG. 4 is a view similar to FIG. 3, but shows another
example fabric distribution layer; and
[0014] FIG. 5 is view similar to FIG. 3, but shows yet another
example fabric distribution layer.
DETAILED DESCRIPTION OF THE INVENTION
[0015] Examples of embodiments that incorporate one or more aspects
of the present invention are described below with references, in
certain respects, to the accompanying drawings. These examples are
not intended to be limitations on the present invention. Thus, for
example, in some instances, one or more examples of the present
invention described with reference to one aspect or embodiment can
be utilized in other aspects and embodiments. In addition, certain
terminology is used herein for convenience only and is not to be
taken as limiting the present invention.
[0016] FIG. 1 schematically illustrates an example embodiment of
the invention wherein an evaporative cooling system, or evaporative
cooler, indicated generally at 10, is included as a component of an
air-conditioning system, indicated generally at 40. The
air-conditioning system, including the evaporative cooler 10, is
operably associated with a gas turbine system.
[0017] A compressor 52 at the gas turbine system 50 functions to
draw ambient air into the air inlet 41 of the air-conditioning
system 40 and through the air-conditioning system. After being
suitably conditioned at the air-conditioning system 40, the air
streams through the adapter duct 44 (sometimes referred to as a
transition duct or bellmouth) to the compressor 52. The conditioned
air, upon entering the compressor 52, is compressed to relatively
high pressures. Thereafter, the compressed air enters a combustion
area 54 where the compressed air is mixed with a fuel such as
natural gas, for example, and the mixture is burned to produce
high-pressure, high-velocity gases that are the product of the
combustion that takes place in the combustion area 54. The
high-pressure, high-velocity gases proceed to a turbine 55
possessed with considerable energy and drive the blades of the
turbine that are attached to an output shaft 56. The rotation of
the turbine blades causes the output shaft 56 which is attached to
rotate as well, and the energy of the output shaft 56 as it rotates
is delivered to a generator 58 and electrical energy thereby
produced at the generator as will be understood by those having
ordinary skill in the art. The use of gas turbine systems is not
limited to electrical power generation, however, and the turbine
systems also can be applied, for example, to driving pumps and
compressors.
[0018] For optimum plant operation, air from the ambient
environment is used at the gas turbine system 50. The ambient air
may first be conditioned and that is accomplished at the
air-conditioning system 40. Again referring to FIG. 1, as noted
above, ambient air, under the influence of the compressor 52, is
drawn into the air-conditioning system at air inlet 41. The ambient
air first enters a filter chamber 42 where particulate matter,
including in some cases water droplets, is removed from the ambient
air. Thereafter, the filtered air passes through the evaporative
cooler 10, the operation of which is discussed in greater detail
below. However, it is noted here that the evaporative cooler
functions to cool the filtered air and increases its density; and,
as noted above, the denser air provides a higher mass flow rate and
pressure ratio at the gas turbine system 50, resulting in an
increase in turbine output and efficiency.
[0019] The filtered and cooled air that exits the evaporative
cooler 10 flows to demisters 43 which remove unwanted water from
the air. From the demisters, the air flows into the adapter duct 44
and from the adapter duct the conditioned air flows to the gas
turbine system 50 where the conditioned air after being compressed
is mixed with fuel and burned as described above. The arrows in
FIG. 1 are all indicative of the flow of the air from its entry
into the air-conditioning system 40 at the air inlet 41 to the
delivery of the air at the compressor 52 of the gas turbine system
50.
[0020] The evaporative cooler 10 itself includes an evaporative
pad, indicated generally at 12 in FIG. 2, that includes an
air-entry surface 14 at which air delivered to the evaporative pad
from the filter chamber 42 enters and passes through the
evaporative pad. The evaporative pad 12 also includes an
air-exiting surface 16 at which air passing through the evaporative
pad, and cooled at the pad, exits from the evaporative pad. The
evaporative pad 12 further includes a liquid coolant-receiving
surface 18 at which a liquid coolant (e.g., cooling liquid)
distributed to the evaporator pad is received and thereafter passes
into the evaporative pad. Although various types of liquid coolants
can be employed with evaporative coolers, in the example
illustrated in the drawings water, either treated or untreated, or
in an aqueous solution can be used as the liquid coolant. Untreated
water can include raw water taken from the environment or water
that has been treated only for the purpose of making it potable.
Treated water would include water that has been treated in order to
render it more suitable for application to evaporative coolers.
Water that has been demineralized and/or treated with surfactants
and/or fungicides and bactericides are examples of treated water.
Aqueous solutions would include homogeneous mixtures in which water
is the solvent.
[0021] A reservoir 20 is provided at the air-conditioning unit
adjacent the bottom of the evaporative pad 12 as an adjunct to the
evaporative cooler 10. Liquid coolant (e.g., water) 27 (shown in
FIG. 3) is added to the reservoir 20 (FIG. 1) through liquid inlet
21 in order to maintain sufficient liquid coolant in the reservoir
for the purpose of delivering the liquid in adequate amounts to the
liquid coolant-receiving surface 18 of the evaporator pad. The
delivery of the liquid coolant is accomplished, for example, by
means of a pump 24 that pumps liquid from the reservoir 20 through
a conduit 25 to a liquid-delivery header 26, which is an example of
a liquid coolant delivery member for delivering liquid coolant to a
location above the evaporative pad 12. The liquid-delivery header
26 delivers liquid coolant 27 (shown in FIG. 3) to a liquid coolant
distribution trough 28 (see FIGS. 1-3) that temporarily retains a
volume of the liquid coolant, and, from the trough, the liquid
coolant flows to the liquid coolant-receiving surface 18 of the
evaporative pad 12. The liquid-delivery header 26 can be configured
so as to deliver the liquid coolant 27 in relatively equal amounts
along the length (L, see FIG. 2) and across the width (W, see FIG.
2) of the liquid coolant distribution trough 28. From the liquid
coolant- receiving surface 18, the liquid coolant 27 flows
downwardly towards the bottom of the evaporative pad 12. The
reservoir 20 also includes a drain 23 for removing sludge from the
bottom portion of the reservoir that may accumulate over time.
[0022] The liquid coolant 27 distributed to the liquid
coolant-receiving surface 18 and passing into the evaporative pad
12 wets the evaporator pad as the liquid coolant flows downwardly
through the pad and, thereby, the liquid coolant tends to be
retained, at least in part, at the evaporator pad. To the extent
that the liquid coolant 27 is not retained at the evaporative pad
12, the liquid coolant will flow from the evaporator pad at a
liquid coolant-exiting surface 19 that is included as a part of the
evaporator pad. Thus, the liquid coolant 27, water in the presented
example, which passes entirely through the evaporative pad 12 exits
the evaporative pad at the liquid coolant-exiting surface 19.
[0023] Based on the foregoing description, it will be understood
that the air-entry surface 14, the air-exiting surface 16, the
liquid coolant-receiving surface 18 and the liquid coolant-exiting
surface 19 of the evaporative pad 12 are arranged so that air
flowing from the air-entry surface 14 to the air-exiting surface 16
through the evaporative pad 12 and liquid flowing from the liquid
coolant-receiving surface 18 towards the liquid coolant-exiting
surface 19 through the evaporative pad come into contact with one
another. As a result of this contact of the air and the liquid
coolant 27, the liquid coolant evaporates so that the air flowing
from the air-entry surface 14 to the air-exiting surface 16 through
the evaporative pad is cooled.
[0024] The evaporative pad 12 can be made of any one of a number of
evaporative cooling media. One example of a medium that can be used
is plastic fibers. Corrugated structures, including structures made
of corrugated cellulose or plastics also can be used. It can be
important that, whatever medium is used, a large surface area be
presented to the coolant and the air flowing through the
evaporative pad so that cooling of the air upon contact with the
liquid coolant is carried out efficiently. It also can be important
that the evaporative cooling medium employed have the properties of
providing for the relatively even distribution and good retention
of the coolant at the medium.
[0025] Turning to a discussion of the construction of the liquid
coolant distribution trough 28, as best illustrated in FIGS. 2 and
3, the example liquid coolant distribution trough can take the form
of a trough that has sloping sides 29 that extend down from an open
top 30 and that are inclined toward one another in the direction of
the bottom of the trough. It will be understood to those skilled in
the art that the sides of the trough need not be sloping as shown
in the drawings but can be arranged so as to be positioned
substantially vertically. The liquid coolant distribution trough 28
includes an open, upper portion 32, adjacent to/extending from the
open top 30, and a lower portion 34. The open top 30 is open to the
liquid-delivery header 26. Thus, the open top 30 is opposing to the
liquid-delivery header 26. Recall that the liquid-delivery header
26 can be configured so as to deliver the liquid coolant in
relatively equal amounts along the length L and across the width W
of the trough 28. As such the liquid-delivery header 26 can be
configured so as to deliver the liquid coolant in relatively equal
amounts along the length L and across the width W of the open top
30 of the trough 28.
[0026] The upper portion 32 of the liquid coolant distribution
trough 28 can be constructed of sheet material such as stainless
steel or plastic sheeting for example and be configured to hold the
liquid coolant so that the coolant cannot flow outwardly at the
first portion of the liquid coolant distribution trough and can
flow only downwardly in the trough. The lower portion 34 of the
liquid coolant distribution trough 28 is contiguous with the upper
portion 32 and includes a lower opening 36 at the base of the lower
portion. Within the shown example, the opening 36 has dimensions W
and L.
[0027] The lower portion 34 also includes a fabric distribution
layer 37 (FIG. 2) that is supported in place within the trough 28
over the lower opening 36. It should be appreciated that the fabric
distribution layer is schematically/generically shown as an example
within the figures. The appearance of the fabric distribution layer
37 can be varied from the example shown within the figures. The
liquid coolant 27 (FIG. 3) temporarily held in the upper portion 32
of the liquid coolant distribution trough passes through the
opening 36 and the fabric distribution layer 37 and is distributed
to the liquid coolant-receiving surface 18 (FIG. 2) of the
evaporative pad 12. As such, the fabric distribution layer 37 is
permeable. With regard to the liquid coolant 27 (FIG. 3)
temporarily held within the upper portion 32 it is to be
appreciated that although the fabric distribution layer 37 is
permeable, a certain about of resistance to permeation is provided
by the fabric distribution layer 37. As such, the entity of the
fabric distribution layer 37 has at least some liquid coolant
located there-above. Accordingly, the entity of the fabric
distribution layer 37 is wet as the liquid coolant passes
therethrough. In view of the action of liquid coolant passing
through the fabric distribution layer 37, the distribution of
liquid coolant exiting the bottom of the fabric distribution layer
37 and through the lower opening 36 is uniformly distributed across
the entire width W and length L of the fabric distribution layer
and thus the entire width W and length L of the lower opening 36.
As such, it should be appreciated that the trough 28 with the
fabric distribution layer 37 is not a pipe. It should further be
appreciated that the trough 28 with the fabric distribution layer
37 is not a conduit pipe with a series of spray or drip nozzles
thereon. Such a pipe with a series of spray or drip nozzles thereon
does not provide the thorough wetting as provided by the trough 28
with the fabric distribution layer 37 in accordance with an aspect
of the present invention. As mentioned, in previous designs,
conduit pipes that drip or spray coolant provide uneven
distribution of coolant.
[0028] In the shown example, the fabric distribution layer 37 is
generally horizontally extending along its length L and across its
width W, and as such liquid coolant held in the upper portion 32 of
the liquid coolant distribution trough 28 is free to migrate as
needed within the upper portion of the trough. Within some specific
examples, an upper surface of the fabric distribution layer 37 is a
flat surface. Such again provides for liquid coolant held in the
upper portion 32 of the liquid coolant distribution trough 28 to be
free to migrate as needed within the upper portion of the
trough.
[0029] In the example illustrated in FIGS. 1 and 2, the liquid
coolant distribution trough 28 is shown as supported somewhat above
the liquid coolant-receiving surface 18 of the evaporative pad 12.
However, the liquid coolant distribution trough 28 can be supported
on and in contact with the liquid coolant-receiving surface 18.
[0030] The fabric distribution layer 37 is sufficiently permeable
to allow liquid coolant held in the upper portion 32 of the liquid
coolant distribution trough to pass through the fabric distribution
layer and distributed to the liquid coolant-receiving surface 18 of
the evaporative pad 12 at a selected rate that is sufficient to
adequately keep the entirety of the evaporative pad wetted with the
coolant so that the entirety of the air flowing through the pad
comes into contact with the coolant and is cooled. One example of a
material from which the fabric distribution layer can be made is
fiberglass padding provided as a fabric. When fiberglass padding is
employed, the padding can be placed over the opening 36 in the
lower portion 34 of the liquid coolant distribution trough and held
in place by the sloping sides 29, 29 of the trough. Another example
of a material that can be used to form the fabric distribution
layer is relatively finely divided plastic material that can be
contained within suitable netting and the finely divided
plastic-filled netting-, provided as a fabric and placed over the
opening 36. As mentioned, the sides of the trough need not be
sloping as shown in the drawings but can be arranged so as to be
positioned substantially vertically. In that case, it can be
necessary to provide retainers of a suitable sort to hold the
fabric distribution layer in place over the opening 36.
[0031] In other examples, the material of the fabric distribution
layer 37 may be synthetic fibrous media fabric. For example, the
media may be spunbond fabric made from polypropylene, polyester,
polyethylene, and/or NYLON fibers. As another example, the media
may be melt blown fabric made from polypropylene, PBT (polybutylene
terepthalate), PET (polyethylene terephthalate), Nylon, and/or
polyethylene fibers. As another example, the media maybe
hydroentangled fabrics made from polypropylene, polyester, PVDF,
and/or PTFE fibers. As another example, the media may be airlaid
calendared fabrics made from polypropylene, polyester, PVDF
(polyvinylidene fluoride), and/or PTFE (polytetrafluoroethylene)
fibers. As another example, the media may be wet laid fabrics made
from microfiber glass and/or polyester fibers. For such media, the
fibers can be mono-component (i.e., having two different materials
in same fiber) or bi-component (i.e., having two different
materials in same fiber). Also, multiple types and/or multiple
techniques may be utilized. Further, the media can also have
multiple layers and the multiple layers can be bonded together,
such as by either thermal or adhesive lamination. The multiple
layers may be the same or different. If the multiple layers are
different, each layer may provide a different property and/or
characteristic. See FIG. 4 for one example that has multiple
layers. It should be noted that the example drawings are
generic/schematic. As such, the multiple layers, the media therein,
etc. can have a different appearance, arrangement, etc.
[0032] As mentioned, the liquid coolant passes through the fabric
distribution layer 37. Accordingly, the fabric distribution layer
has porosity. In some examples, there exists a uniform pore size
across the entire length L and width W of the media. However, it is
contemplated that non-uniform pore sizes can be provided. Pore size
can be chosen based upon one or more criteria. In one example, the
criteria is selected to optimize one or more characteristics
concerning the liquid coolant passing through the fabric
distribution layer 37. Some example criterion include: providing
sufficient back pressure for enabling good liquid distribution,
allowing sufficient liquid flow with minimal liquid head (e.g.,
delivering 1.5 to 2.0 gallons/min/ft.sup.2 or approx. 0.5 to 0.7
liters/min/m.sup.2 of liquid flow with less than 2 inches or
approx. 5 cm of liquid head), and resisting pore fouling by trace
quantity of contaminants present in the liquid coolant (e.g.,
contaminants present in water).
[0033] Further, other features and/or characteristics can be
provided or utilized for the media. For example, hydrophilic or
wicking treatment can be applied to enable good liquid (e.g.,
water) flow. As another example, the media can also be selected for
mechanically durable enough to withstand continuous use for several
years. As a still further example, the media can also be selected
or treated for resist against mildew, mold, etc.
[0034] As mentioned, pore size can be chosen based upon one or more
criteria. Also as mentioned, the media can also have multiple
layers. In some examples, the pore sizes of different layers may be
different. In some further examples, the layers and pores therein
may provide for a gradient (e.g., progressive change) of pore sizes
through media layers. Alternatively, if multiple layers are not
utilized, a gradient structure of pore sizes in the distribution
media could still be provided. The gradient structure of pore sizes
may have various configurations. In one example, finer pores are at
the liquid coolant entrance (e.g., upper) side. It is to be
recalled that the fabric distribution layer 37 and the media
thereof is generically/schematically shown within the figures. As
such, the drawings are to be taken as representing the various
possible examples of the fabric distribution layer 37 and the media
thereof.
[0035] Also, the media or some layers thereof may be membrane(s).
See FIG. 5 for one example that generically/schematically shows a
layer that is a membrane. The shown example presented the membrane
at an upper layer location. However, the membrane could be located
at a lower layer location or an intermediate layer location.
Examples of membranes that can be used are expanded PTFE,
microporous polypropylene or polyethylene, or cast membranes such
as Polyether sulfone, Nylon, PVDF. Some membranes may not be strong
enough to be used as stand-alone layer. For such membranes of
lesser strength, the membrane layer can be attached, such as by
lamination, to a fibrous strength-providing layer. Any of the above
mentioned fibrous layers can be used as a strength-providing layer.
If lamination is utilized, such lamination can be done via either
thermal or adhesive means. In the case of hydrophobic membrane
(e.g., expanded PTFE), the membrane can be prewetted with Isopropyl
alcohol or it could have a permanent hydrophilie treatment applied
on it. As an example, such treatment could be Polyvinyl alcohol
(PVA).
[0036] In order to be most assured that the liquid coolant
distribution trough 28 will function to wet the entirety of the
evaporative pad 12, as best seen in FIG. 2, the perimeter of the
outer boundary of the evaporative pad 12, the perimeter of the
liquid coolant-receiving surface 18 and the perimeter of the
opening 36 in the lower portion 34 of the liquid coolant
distribution trough 28 can be co-extensive with one another. That
is, these elements can have the essentially the same outer
dimensions or limits. Within the one example, the dimensions are
width W by length L. As such the size of the opening 36 is
congruent with the size of the liquid coolant-receiving surface 18
of the evaporative pad 12. Consequently, coolant flowing through
the opening 36 in the liquid coolant distribution trough 28 will
flow to the entirety of the liquid coolant-receiving surface 18 of
the evaporative pad 12; and the liquid coolant passing through the
liquid coolant-receiving surface 18 and into the evaporative pad 12
will flow downwardly and wet the entirety of the evaporative pad 12
so that the entirety of the air flowing through the evaporative pad
will come into contact with the liquid coolant and the entirety of
the flowing air cooled. Thereby, the development of hot spots in
the evaporative pad 12 that can be the cause of damage to the
blades of the compressor and the consequent operational failure of
the gas turbine system can be avoided.
[0037] The entirety of the evaporative pad can be considered to
have been wetted and the entirety of the air can be considered to
have been contacted by the coolant so that the entirety of the air
is cooled whenever the properties of the air passing through the
evaporative pad are only negligibly different from the properties
of air that has passed through the evaporator pad when it has been
wetted in its entirety.
[0038] Another aspect of the invention that can be included in the
construct of the liquid coolant distribution trough 28 concerns
features of the liquid coolant distribution trough that result in
the liquid coolant being distributed to the liquid
coolant-receiving surface 18 of the evaporative pad 12 at a
selected rate. The selected rate would be sufficient to cause the
entirety of the evaporative pad to be wetted by the liquid coolant
flowing from the liquid coolant-receiving surface 18 of the
evaporator pad towards the liquid coolant-exiting surface 19 of the
evaporator pad. However, the selected rate would not be
substantially greater than is required for that purpose and would
be insufficient to cause an excessive amount of the liquid coolant
to exit the liquid coolant-exiting surface 19 of the evaporative
pad 12. In this aspect, the excessive recirculation of the liquid
coolant from the reservoir 20 to the liquid-delivery header 26 is
avoided.
[0039] The rate at which liquid coolant will flow through the
opening 36 in the liquid coolant distribution-trough 28, aside from
the physical properties of the liquid coolant itself such as its
viscosity for example, is dependent on the depth of the liquid
coolant in the trough, or the magnitude of the head of the liquid
coolant in the trough, and the permeability characteristic of the
fabric distribution layer 37. Consequently, in the example of the
invention shown in the drawings, the upper portion 32 of the liquid
coolant distribution trough 28 is configured to maintain the liquid
coolant at a selected depth in the upper portion 32 of the liquid
coolant distribution trough 28 above the fabric distribution layer
37 and the fabric distribution layer has a permeability
characteristic, such that the liquid coolant is distributed to the
liquid coolant-receiving surface 18 of the evaporative pad 12
through the fabric distribution layer 37 at a rate that is
sufficient to cause the entirety of the evaporative pad 12 to be
wetted by the liquid coolant flowing from the liquid
coolant-receiving surface 18 of the evaporator pad towards the
liquid coolant-exiting surface 19 of the evaporator pad but
insufficient to cause an excessive amount of liquid coolant to exit
the liquid coolant-exiting surface of the evaporative pad.
[0040] The depth of the liquid coolant in the liquid coolant
distribution trough can be controlled, simply, by controlling the
height to which the top of the trough extends. In that case,
coolant delivered to the trough would be delivered at a rate such
that coolant would continually flow to outside the trough over the
top of the trough. In the embodiment shown in the drawings,
however, an alternate technique is employed to control the depth of
the liquid coolant. Thus, as best seen in FIGS. 2 and 3, a notch 31
is provided in the rear panel 33 of the liquid coolant distribution
trough 28. The bottom of the notch establishes the height to which
coolant in the trough can be maintained, with the coolant being
delivered to the trough from the liquid-delivery header 26 at a
sufficient rate to cause coolant to continually, but somewhat
slowly, flow through the notch in order to maintain that height.
The coolant flowing from the liquid coolant distribution trough
through the notch 31 can be collected and routed through a conduit,
for example, to the reservoir 20. It will be understood to those
skilled in the art that liquid coolant can be delivered to the
liquid coolant distribution trough 28 using other than the
liquid-delivery header 26 illustrated in FIG. 1. For example, a
simple liquid coolant delivery line can be hung over the top of one
of the sloping sides 29 of the liquid coolant distribution trough.
Alternately, an opening can be made in a side of the upper portion
32 of the trough and the liquid coolant line secured to the opening
at the liquid line's discharge point.
[0041] The permeability characteristic of the fabric distribution
layer 37 can be established in any one or more of a number of ways.
For example, the medium selected to make up the fabric distribution
layer can influence the permeability characteristic of the bed.
Thus, a fabric distribution layer of a fiberglass material can have
a permeability characteristic that is different than the
permeability characteristic of granulated material such as finely
divided plastic spheres. Also, the permeability characteristic of
the fiberglass material itself can be influenced by the density of
the fiberglass material. As well, the permeability characteristic
of the granulated material can be influenced by how tightly the
granules are packed together for example.
[0042] It will be understood from the foregoing description that in
one aspect, the invention can include a method of cooling air
including passing a liquid coolant through an evaporative pad of an
evaporative cooler and wetting the entirety of the evaporative pad
with the liquid coolant as the liquid coolant passes through the
evaporative pad. The method can also include passing the air to be
cooled through the entirely wetted evaporative pad and contacting
the entirety of the air with the entirely wetted evaporative pad,
whereby the entirety of the air passing through the entirely wetted
evaporative pad is cooled. In another aspect, the method can
include distributing the liquid coolant to a liquid
coolant-receiving surface at the evaporative pad by passing the
liquid coolant through a fabric distribution layer before passing
the liquid coolant into the evaporative pad. In still another
aspect, the method can include maintaining the depth of the liquid
coolant in the upper portion of a liquid coolant distribution
trough at a level and the permeability characteristic of the fabric
distribution layer at a value such that the liquid coolant is
distributed to the liquid coolant-receiving surface of the
evaporative pad through an opening in the liquid coolant
distribution trough and the fabric distribution layer that overlies
the opening at a rate that is sufficient to cause the entirety of
the evaporative pad to be wetted by the liquid coolant flowing from
the liquid coolant-receiving surface of the evaporator pad towards
a liquid coolant-exiting surface of the evaporator pad but
insufficient to cause an excessive amount of liquid coolant to exit
from the liquid coolant-exiting surface of the evaporative pad. In
yet further aspects, the invention can include the foregoing
methods wherein liquid coolant distribution troughs and evaporative
pads of the types described above can be employed and the methods
are employed to provide cooled air to a gas turbine system.
[0043] While the present invention has been described above and
illustrated with reference to certain embodiments thereof, it is to
be understood that the invention is not so limited. Thus, the
present invention has applications to evaporative cooler systems,
or evaporative coolers of essentially any type. These include, but
are not limited to, evaporative coolers for cooling air for thermal
comfort and evaporative coolers for controlling the temperature of
the air in structures such as greenhouses and buildings containing
livestock.
[0044] Modifications and alterations will occur to those skilled in
the art upon reading and understanding the specification, including
the drawings. In any event, the present invention covers and
includes any and all modifications and variations to the described
embodiments that are encompassed by the following claims.
* * * * *