U.S. patent application number 14/217723 was filed with the patent office on 2014-11-20 for multi-stage evaporative heat rejection process cycle that facilitates process cooling efficiency, water production, and/or water reclamation for fluid coolers and cooling towers.
The applicant listed for this patent is Inertech IP LLC. Invention is credited to Earl Keisling.
Application Number | 20140338391 14/217723 |
Document ID | / |
Family ID | 51894687 |
Filed Date | 2014-11-20 |
United States Patent
Application |
20140338391 |
Kind Code |
A1 |
Keisling; Earl |
November 20, 2014 |
MULTI-STAGE EVAPORATIVE HEAT REJECTION PROCESS CYCLE THAT
FACILITATES PROCESS COOLING EFFICIENCY, WATER PRODUCTION, AND/OR
WATER RECLAMATION FOR FLUID COOLERS AND COOLING TOWERS
Abstract
An evaporative heat rejection cycle for cooling a heat load is
presented, including an environmental pre-cooling primary
evaporator, an environmental pre-cooling secondary evaporator, a
pre-cooled evaporative heat rejection cycle section in thermal
communication with a heat load, and a primary pre-cooling
evaporative heat exchanger in thermal communication with air that
is drawn into thermal communication with a primary evaporator
cycle, to enable heat transfer and moisture elimination from the
air to a first fluid, where a portion of the first fluid evaporates
and absorbs heat and condenses moisture from the air.
Inventors: |
Keisling; Earl; (Ridgefield,
CT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Inertech IP LLC |
Danbury |
CT |
US |
|
|
Family ID: |
51894687 |
Appl. No.: |
14/217723 |
Filed: |
March 18, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61801966 |
Mar 15, 2013 |
|
|
|
Current U.S.
Class: |
62/513 |
Current CPC
Class: |
F25B 25/00 20130101;
F25B 23/006 20130101; Y02B 30/54 20130101; F24F 5/0035 20130101;
F25B 39/02 20130101; F25B 2339/047 20130101 |
Class at
Publication: |
62/513 |
International
Class: |
F25D 17/02 20060101
F25D017/02; F25B 39/04 20060101 F25B039/04; F25D 17/04 20060101
F25D017/04; F25B 39/02 20060101 F25B039/02 |
Claims
1. An evaporative heat rejection cycle for cooling a heat load,
comprising: an environmental pre-cooling primary evaporator; an
environmental pre-cooling secondary evaporator; a pre-cooled
evaporative heat rejection cycle section in thermal communication
with the heat load; and a primary pre-cooling evaporative heat
exchanger in thermal communication with air that is drawn into
thermal communication with the primary evaporator to enable heat
transfer and moisture elimination from the air to a first fluid,
wherein a portion of the first fluid evaporates and absorbs heat
and condenses moisture from the air, wherein the first fluid
transports the heat to a condenser where it is in thermal
communication with a second fluid that at least partially condenses
the first fluid, wherein the second fluid is circulated to a
discharge pipe with atomizing spray nozzles that are in thermal
communication with the air that is being pulled through a closed
evaporative heat rejection chamber, wherein the second fluid is in
contact with the air and creates a film on the fill or evaporator
coil to enable partial water evaporation to the atmosphere as well
as cooling the remaining first fluid as it travels down through a
circuit in thermal contact with the air, wherein a portion of the
cooled second fluid drops and collects at a cold water basin, and
wherein the second fluid is circulated from the cold water basin
and is pumped to the condenser to repeat the cycle.
2. The heat rejection cycle according to claim 1, further
comprising a secondary pre-cooling evaporative section in thermal
communication with the pre-cooled air, wherein the air is in
thermal contact with the secondary pre-cooling evaporative section
to enable further heat and moisture elimination to a third fluid,
the third fluid being circulated to another evaporator, the third
fluid being in thermal communication with a fourth fluid which
evaporates the rejected heat into the fourth fluid, the fourth
fluid being pulled through the suction of a compressor.
3. The heat rejection cycle according to claim 2, wherein the
compressor compresses the fourth fluid and delivers it to another
condenser where it is in thermal communication with the second
fluid which fully condenses the fourth fluid into a liquid and
wherein the fourth fluid liquid is transported through an expansion
valve, wherein the fourth fluid expands and evaporates in thermal
communication with the third fluid in the another evaporator.
4. The heat rejection cycle according to claim 3, wherein, the
second fluid which is in thermal communication with the fourth
fluid at the condenser, is circulated to the discharge pipe with
the atomizing spray nozzles that are in thermal communication with
the air that is being pulled through the closed evaporative heat
rejection chamber.
5. The heat rejection cycle according to claim 4, wherein the
second fluid is in contact with the air and creates the film on the
fill or the evaporator coil to enable partial water evaporation to
the atmosphere, as well as to cool remaining first fluid as it
travels down through the circuit in thermal contact with the
air.
6. The heat rejection cycle according to claim 5, wherein a portion
of the cooled second fluid drops and collects at the cold water
basin and wherein the second fluid is circulated from the
cold-water basin and is pumped to the condenser to repeat the
cycle.
7. The heat rejection cycle according to claim 6, wherein the
atmospheric air enters the cycle at the primary pre-cooling
evaporator and is either pushed or pulled through the cycle
utilizing fans, wherein the air is pre-cooled, a portion of the
moisture in the air is eliminated, and the air is transported to
the secondary pre-cooler evaporator.
8. The heat rejection cycle according to claim 7, wherein the cool
air enters the air chamber and is pushed or pulled across and up
through the evaporative heat rejection chamber where it is in
thermal contact with the second fluid.
9. The heat rejection cycle according to claim 8, wherein warm
heated air is either rejected into the atmosphere, or warm latent
air enters into the secondary after cooler evaporator.
10. A primary after-cooler evaporative heat exchanger in thermal
communication with warm process heat rejection air is drawn into
thermal communication with a primary after-cooler evaporator cycle,
to enable heat transfer and moisture elimination from air to a
first fluid, the heat exchanger enabling: a portion of the first
fluid to evaporate and absorb heat and condense moisture from the
air; the first fluid to transport heat to a condenser where it is
in thermal communication with a second fluid that at least
partially condenses the first fluid; and the second fluid to be
circulated to a discharge pipe with atomizing spray nozzles that
are in thermal communication with the air that is being pulled
through a closed evaporative heat rejection chamber.
11. The heat exchanger according to claim 10, wherein the second
fluid is in contact with the air and creates a film on a fill or
evaporator coil to enable partial water evaporation to the
atmosphere, as well as to cool remaining first fluid as it travels
down through a circuit in thermal contact with the air.
12. The heat exchanger according to claim 11, wherein a portion of
the cooled second fluid drops and collects at a cold water basin
and wherein the second fluid is circulated from the cold-water
basin and is pumped to the condenser to repeat the cycle.
13. The heat exchanger according to claim 12, further comprising a
secondary after-cooler evaporative section in thermal communication
with the pre-cooled air, wherein the air is in thermal contact with
the secondary pre-cooling evaporator to enable further heat and
moisture elimination to a third fluid, the third fluid being
circulated to another evaporator where it is in thermal
communication with a fourth fluid which evaporates the rejected
heat into the fourth fluid, the fourth fluid being pulled through a
suction of a compressor.
14. The heat exchanger according to claim 13, wherein the
compressor compresses the fourth fluid and delivers it to another
condenser where it is in thermal communication with the second
fluid which fully condenses the fourth fluid into a liquid.
15. The heat exchanger according to claim 14, wherein the fourth
fluid liquid is transported through an expansion valve, where it
expands and evaporates in thermal communication with the third
fluid in the another evaporator.
16. The heat exchanger according to claim 15, wherein the second
fluid, which is in thermal communication with the fourth fluid at
the condenser, is circulated to the discharge pipe with the
atomizing spray nozzles that are in thermal communication with the
air that is being pulled through the closed evaporative heat
rejection chamber and wherein the second fluid is in contact with
the air and creates the film on the fill or evaporator coil to
enable partial water evaporation to the atmosphere, as well as to
cool the remaining first fluid as it travels down through the
circuit in thermal contact with the air.
17. The heat exchanger according to claim 16, wherein the second
fluid is circulated from the cold-water basin and is pumped to the
condenser to repeat the cycle, and a warm heat rejection air enters
the cycle at the primary pre-cooling evaporator where it is either
pushed or pulled through the cycle by utilizing fans.
18. The heat exchanger according to claim 17, wherein the air is
pre-cooled, a portion of the moisture in the air is eliminated, and
the air is then transported to the secondary pre-cooler evaporator,
and wherein the cool air enters an air chamber and is pushed or
pulled across and up through the evaporative heat rejection chamber
where it is in thermal contact with the second fluid.
19. The heat exchanger according to claim 18, wherein the warm
heated air enters into the primary after-cooler evaporator where
the air is after-cooled and a portion of the moisture is
eliminated.
20. The heat exchanger according to claim 19, wherein the air
enters the secondary after-cooler evaporator where the air is
further cooled and additional moisture is eliminated, and wherein
the cooler dry air is discharged into the atmosphere or is
distributed as conditioned air.
Description
BACKGROUND
[0001] Evaporative heat rejection equipment is commonly used to
reject waste heat into the atmosphere that has been absorbed from
power generation processes, radiator processes, industrial
processes, or refrigeration cooling process cycles. The evaporative
heat rejection equipment includes at least cooling towers,
evaporative coolers, surface condensers, and fluid coolers. The
evaporative heat rejection equipment is often configured in a tower
structure that facilitates the evaporative cooling process.
[0002] Wet bulb-driven evaporation systems enable higher system
energy efficiencies versus dry bulb-dependent equipment due to the
requirement for higher fan horse power requirements for dry
condensing heat rejection. Also, dry bulb-driven heat rejection
processes generally produce higher temperature process water which
is less efficient and adds operational costs to the cycles they
serve. The evaporative process utilizes water, in either a spray
mist, drizzle, or water fall type process to enable contact time
with the wet-bulb atmosphere to effectively absorb heat into the
atmosphere and manufacture lower coolant fluid temperatures. These
systems are two or three component fluid cooling systems in which
air and water, or in some instances, glycol are the only fluids
involved in the evaporative cooling process.
[0003] There are several disadvantages to the evaporative heat
rejection process including the requirement of large quantities of
potable water. Since water is a precious resource, and has limited
availability in certain regions, the evaporative heat rejection
process has an impact on the earth's water resources.
[0004] Present day cooling towers, fluid coolers and surface
condensers produce relatively cold process water based on a
relationship between the atmospheres wet bulb condition, the
contact time of the water, the flow of the water, and the air
current that is pulled through the cycle using a fan. The delta
temperature difference of leaving process water temperature versus
available wetbulb is referred to as wet bulb approach temperature.
The approach of a particular heat rejection cycle has limitations
based on fan horse power, and the maximum contact time that the
water can stay in contact with the atmosphere to reject heat. It is
normal for the process water production temperature to be within
5-9 degrees .degree. F. of wetbulb. In some instances, there is
equipment that can produce 3-5 degrees .degree. F. process water.
However, this equipment requires oversizing of fans, structure,
fill, and/or coils in order to produce lower delta wetbulb approach
temperatures.
[0005] Conventional water-cooled heat rejection equipment in their
current form have significant inherent limitations in their ability
to produce lower temperature process water or fluids. They are
reliant on environmental decreases in atmospheric conditions in
order to produce lower temperature fluids.
[0006] Conventional water cooled heat rejection equipment in their
current form have significant inherent limitations in their ability
to change and optimize their coolant production operation over a
full spectrum of environmental weather and load conditions. Their
performance capabilities are limited to, and reliant on, the
present environmental temperature and humidity conditions
(enthalpy) of the atmosphere in which they are operating.
[0007] Conventional water cooled heat rejection equipment in their
current form require significant chemical treatment systems in
order to control internal and external water and air borne
bio-hazards, in addition to corrosion inhibiting measures in the
pipe system.
[0008] Conventional heat rejection equipment are limited in their
air flow patterns. Such heat rejection equipment are either a 100%
draw-through or 100% blow-through air exchange of air within the
environment. They are full air pass-through cycles. The coolant
production process can be varied by varying the production water
flow rates (basin pumps on or off), the coolant flow rates
(condenser water pumping variable frequency drives (VFDs) or speed
controls), or the air flow rates (fan VFDs or speed controls).
[0009] Conventional heat rejection equipment (e.g., towers, fluid
coolers, evaporative coolers, etc.) in their current form are not
capable of effectively containing, capturing or processing the
intake vapor that is present in the air that passes into the cycle
in advance of the heat rejection process.
[0010] Conventional heat rejection equipment (e.g., towers, fluid
coolers, evaporative coolers, etc.) in their current form are not
capable of effectively containing, capturing or processing the
vapor that is discharged into the atmosphere that is a by-product
of the heat rejection process.
[0011] Conventional heat rejection equipment (e.g., towers, fluid
coolers, evaporative coolers, etc.) in their current form are not
capable of producing potable (distilled) water as a by-product of
the cycle.
[0012] Conventional heat rejection equipment (e.g., towers, fluid
coolers, evaporative coolers, etc.) rely on external feeds for
water in their current form, and are not capable of extracting
water out of the atmosphere and utilizing that water in their
cycle. Rather, the cycle consumes tremendous amount of potable
water.
[0013] Conventional heat rejection equipment (e.g., towers, fluid
coolers, evaporative coolers, etc.) have limited ability to
regulate the leaving process water temperature. The limitations
are, for example, atmospheric conditions, fan speed, water flow
rates, and control water pipe bypasses. Water cooled refrigeration
cycles require additional power (kw/ton increases) with each degree
of increase of process condenser water temperature.
[0014] Conventional water cooled refrigerant cycles that operate in
high wetbulb environments, and rely on cooling towers, fluid
coolers, for their process water, require more power to operate in
these harsher environments.
SUMMARY
[0015] The present disclosure relates to a heat rejection cycle
that can produce and process its own water from the environment,
reclaim and process discharge vapor which produces additional
distilled water, facilitate greater efficiencies on process water
production and dramatically increase chiller efficiency
performance.
[0016] The cycle significantly improves system fluid production
temperature tolerances to provide a more stable environment for
refrigeration circuits that may be fed from the heat rejection
equipment.
[0017] The cycle can operate as an atmospheric water pre-production
unit. The entering air can be efficiently lowered to effectively
draw out moisture (condensed) from the available atmosphere in an
effort to produce all or a portion of the water that will be
consumed in the evaporative heat rejection process that will occur
further down stream in the cycle.
[0018] The cycle can process and reclaim the water vapor that is
produced in the evaporator heat rejection cycle. This can be
accomplished utilizing limited mechanical DX compression and very
low kw/ton ratios. The water is potable quality water which can be
harvested for re-use in the cycle or for other purposes.
[0019] The cycle can deliver cool fresh conditioned air as a
by-product of the after cooler water recovery cycle. This air can
be used to cool various loads, electronics equipment, or other
heating ventilation, and/or air-conditioning (HVAC) or process
cooling needs.
[0020] The cycle is not reliant on atmospheric conditions alone to
produce lower temperature process water. Rather, it has the ability
to treat and lower the inlet wet-bulb conditions to produce a
desired lower temperature process water with very little
energy.
[0021] The cycle significantly reduces the need for chemicals that
are normally required for biological and corrosion purposes in the
process water. This is because a majority of the water that is
introduced into the cycle has been extracted and condensed from the
atmosphere. This process produces clean fresh water that is free of
contaminants and is PH neutral.
[0022] Moreover, the cycle has an environmentally friendly impact.
The cycle requires less blow-down cycle discharges versus a
traditional cooling tower or fluid cooler cycle that rely on water
from external sources that may not be good quality water free of
particulate(s) or adverse PH quality. The requirement for less
frequent blow-downs aids in the conservation of water and
facilitates greater production capacity for other uses. Since the
cycle can utilize better quality water that it processes and
produces, it significantly lessens the impact on sewage discharges
that are necessary with traditional towers and fluid cooler
systems.
[0023] The system water production and internal chamber temperature
control can be finely tuned, thus enabling an optimized cycle that
is not normally possible with standard cooling towers and fluid
cooler systems. The cycle can be optimized for colder water
production processes, water conservation, and discharge of air
conditioning. Normally the control of these various system cycles
are in silos and are not directly interrelated or interconnected.
This holistic system approach to the inter-related cycles enables
simple close tolerance algorithms which can proportionally control
the system in relation to changes in environmental conditions,
water production needs, and energy efficiency enhancements for the
load system.
[0024] The system utilizes a stepped proportional in-series cooling
approach for the pre-cooling inlet and after-cooling discharge air
treatment. This in-series stepped approach to cooling the air
enables the majority of the cooling load to be handled with a
pumped refrigerant solution, and then a resultant smaller portion
to be accomplished with a compressed direct expansion (DX)
cycle.
[0025] By pre-cooling the inlet air, and creating a lower
temperature environment in the chamber of the cycle, load process
cooling can be accomplished at extremely high efficiencies and at
low kw/ton ratios. At the same time, the lower false atmosphere in
the chamber facilitates lower temperature process water production
with a net savings of overall system energy use.
[0026] The water vapor recovery system includes an add-on dual air
circuit. This circuit adds a benefit to the overall system
efficiency, by producing clean fresh water that can be reused in
the cycle, thus enabling better heat transfer in the pipe system
and equipment, and further reducing chemical treatment
requirements. The system is includes the same dual in-series
cooling evaporators with the primary cooling being performed by the
efficient pumped refrigerant circuit, and the resultant load
handled by the secondary smaller DX circuit.
[0027] The exemplary circuits described in this application apply
to new cooling towers, fluid coolers, as well as retrofit
applications. The evaporators, refrigerant cycles, and control
systems can be either factory applied to new equipment or
retrofitted to existing equipment.
[0028] The cycle equipment can be fitted with discharge duct
connections to facilitate delivery of cold conditioned air.
[0029] The cycle apparatus can be fitted with discharge air, face
and bypass dampers, enthalpy control, and inlet air connections to
facilitate greater efficiencies at the intake air assembly of the
cycle. The heat load at the intake pre-cool evaporators can be
reduced by allowing a portion of the cold discharge air to be
ducted in a bypass arrangement back to the inlet of the apparatus.
This can be done on either new factory equipment or retrofitted on
existing fluid coolers and cooling towers.
[0030] Further scope of applicability of the present disclosure
will become apparent from the detailed description given
hereinafter. However, it should be understood that the detailed
description and specific examples, while indicating preferred
embodiments of the present disclosure, are given by way of
illustration only, since various changes and modifications within
the spirit and scope of the present disclosure will become apparent
to those skilled in the art from this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] The above and other aspects, features, and advantages of the
present disclosure will become more apparent in light of the
following detailed description when taken in conjunction with the
accompanying drawings in which:
[0032] FIG. 1 is a schematic diagram illustrating a cooling tower
with an inlet air pre-cooling dual refrigerant evaporator circuit,
in accordance with the embodiments of the present disclosure;
[0033] FIG. 2 is a schematic diagram illustrating a cooling tower
with an inlet air pre-cooling, as well as a discharge air after
cooler dual refrigerant evaporator circuit, in accordance with the
embodiments of the present disclosure;
[0034] FIG. 3 is a schematic diagram illustrating a fluid cooler
with an inlet air pre-cooling as well as a discharge air after
cooler dual refrigerant evaporator circuit, in accordance with the
embodiments of the present disclosure;
[0035] FIG. 4 is a schematic diagram of a face and bypass and
ducted connections from the discharge to the air inlet of the
apparatus, in accordance with the embodiments of the present
disclosure; and
[0036] FIG. 5 are schematic diagrams of various air flow patterns
including induced and forced draft flow air flow patterns for
cooling towers and fluid coolers, in accordance with the
embodiments of the present disclosure.
[0037] The figures depict preferred embodiments of the present
disclosure for purposes of illustration only. One skilled in the
art will readily recognize from the following discussion that
alternative embodiments of the structures and methods illustrated
herein may be employed without departing from the principles of the
present disclosure described herein.
DETAILED DESCRIPTION
[0038] Particular embodiments of the present disclosure are
described hereinbelow with reference to the accompanying drawings;
however, it is to be understood that the disclosed embodiments are
merely exemplary of the disclosure and may be embodied in various
forms. Well-known functions or constructions are not described in
detail to avoid obscuring the present disclosure in unnecessary
detail. Therefore, specific structural and functional details
disclosed herein are not to be interpreted as limiting, but merely
as a basis for the claims and as a representative basis for
teaching one skilled in the art to variously employ the present
disclosure in virtually any appropriately detailed structure.
[0039] The term "exemplary" is used herein to mean "serving as an
example, instance, or illustration." Any embodiment described
herein as "exemplary" should not necessarily be construed as
preferred or advantageous over other embodiments. The word
"example" may be used interchangeably with the term
"exemplary."
[0040] The present disclosure relates to an apparatus that is
capable of efficiently improving environmental conditions
(wet-bulb) in order to optimize chiller and other heat rejection
processes. The apparatus can be fitted with inlet dual stage heat
rejection coils that can lower the inlet latent and sensible air
loads to create a more efficient false atmosphere within the air
chamber, that enables the production of colder process water. By
lowering the chamber atmospheric wet bulb temperature the apparatus
can produce colder process water. The production of colder process
water facilitates greater efficiencies on the load side or system
side that the apparatus is serving as a heat rejection apparatus.
As a result of the production of lower temperature process water,
chillers and other equipment connected to the apparatus exhibit
higher efficiencies. For instance a chiller gains approximately 2%
efficiency per each degree lowered on the supply condenser
(processor) water. Since the inlet pre-cooling cycle can lower the
inlet air temperature with minimal energy expended, there are
significant net savings in energy across the system. The total
combined power use in the system is significantly reduced because
the load system equipment exhibits high efficiency gains due to the
production of cooler process water through the false atmosphere. It
therefore enables a net energy system savings in addition to
producing water and re-claiming water.
[0041] The inlet air pre-cooler evaporator circuits are capable of
lowering the entering air temperature conditions through a dual (or
stepped) cooling process. This process lowers the enthalpy of the
entering air to a controlled and desired set-point. The staged
process which uses a plural refrigerant pumped solution is able to
cool the entering air incrementally through a series of inlet air
evaporator coils. The staged cooling process offers a highly
efficient cooling kw/ton ratio.
[0042] The majority of the entering air heat load (about 50-75%) is
accomplished without utilizing direct mechanical compression
assistance. The primary heat load is absorbed into the evaporator
utilizing a pumped refrigerant. The pumped liquid refrigerant
temperature (saturation line) set point is at approximately 1
degree below the desired leaving air temperature off of the primary
inlet air evaporator. The temperature of the pumped liquid supply
refrigerant correlates directly to the temperature of the related
condenser water supply water temperature. The refrigerant
condensing line is maintained at approximately 0.5 to 1 degree
approach temperature. This approach temperature is the delta, T,
between the entering supply condenser water at the condenser versus
the leaving fully condensed pumped refrigerant, which is then
supplied to the primary air evaporator coil.
[0043] The available condenser water supply temperature in the cold
water basin is cooler than it would normally be if the pre-cooler
evaporators did not pre-treat and lower the entering outside
entering air to the desired leaving air temperature entering the
air chamber. The cooler pre-treated air is then pulled up through
(or pushed through in a cross-flow cycle) where it is in contact
with the water film that is moving its way down the cooling tower
fill or condensing coil if it is a fluid cooler cycle. The water
collects in the cold water basin after it has completed its
interaction with the cold air stream in the air chamber. This
cooler process water can be delivered to the external process
equipment that it feeds, and it is available to feed the condensing
equipment, including the internal refrigerant circuits that
pre-cool the entering, and if applicable, after-cooler
circuits.
[0044] The inlet air pre-cooler cycle evaporator coils can be
located on a single or multi-sided faced towers or fluid
coolers.
[0045] In the instance of multiple face inlet air pre-coolers cycle
evaporators they can be fed from (i) a common primary or (ii)
multiple primary and secondary refrigerant circuits.
[0046] The pre-cooler inlet and after-cooler outlet evaporators can
be fed from (i) common or (ii) multiple primary and secondary
refrigerant circuits.
[0047] The final after-cooler evaporative cooling circuits can
further remove a portion of the heat load that has been introduced
into the airstream from the process return water. The level of heat
rejection that is accomplished at the after cooler is dependant on
the cycle demand requirements for moisture removal or cold fresh
air production.
[0048] The after-cooler evaporator circuits can be fitted with
similar air flow and refrigerant circuits to the pre-cooling inlet
air cycles. The initial heat load of about 50-75% can be
accomplished at the primary evaporator coil before it enters the
secondary pre-cooler evaporator. The resultant load on the
secondary after cooler evaporator is reduced by approximately
50-75% similar to the pre-cooler evaporator cycles.
[0049] This final heat load is accomplished utilizing a compression
circuit which operates on an in-series refrigerant to the
refrigerant circuit. The system coefficient of performance and
kw/ton are significantly lower than normal operating DX refrigerant
systems because the overall "lift" of the refrigerant circuit is
approximately only about 10-15% that of a normal DX compression
system. This is due to the availability of cold process condenser
water, which is produced as a by-product of the pre-cooler and
water recovery system at the air inlet to the system.
[0050] The apparatus can be housed in or attached to a traditional
cooling tower, or fluid cooler structures, or can be arranged in
typical draw-through or blow-through air handling unit style coil
and fan configurations.
[0051] The types of fans utilized in the apparatus can vary by
efficiency performance.
[0052] The type of evaporation media, tower fill, condensing coils,
wicking material and water contact evaporation mass, or
combinations thereof are interchangeable to enable greater
efficiencies in fan horsepower performance and better heat
transfer.
[0053] The system utilizes conventional micro-channel evaporator
coils, however, if future coil technology facilitates greater air
pressure efficiency (lower static pressure losses), or better heat
transfer coil characteristics they may be substituted. One skilled
in the art may contemplate a plurality of different evaporator
coils. The exemplary systems of the present disclosure are not
limited with regard to evaporator coils.
[0054] The apparatus can be housed in an enclosure including face
and bypass modulating intake and discharge dampers. Modulation of
the dampers enables full proportional control of the air intake
from and air discharge to the external environment, as well as
regulation of the amount and quality of air that is taken and
rejected (enthalpy control). It is noted that the spray water cycle
and the collection basin allows the apparatus to act as an
evaporative cooler.
[0055] The in-series evaporator coils are capable of reducing the
high latent air sufficiently below the dew point in order to
extract water from the high latent vapor. The coils can also be
utilized to lower the effective wet bulb condition ahead of the
heat rejection coil, thereby creating a "false atmosphere." This
facilitates greater efficiency benefits for producing cooler
leaving water off the heat rejection coil(s). By placing the coils
in series, the cycle to cool the entering hot latent air is
enabled. The air is cooled as it enters the primary heat exchanger
evaporator coil.
[0056] The heat absorption is accomplished by rejecting the heat
through the process of latent heat of vaporization. The heat is
absorbed into the pumped liquid refrigerant that is present at the
evaporator heat exchanger. The refrigerant cycle utilizes a pump to
deliver liquid refrigerant to the evaporator coil. It is an "over
feed" or "over-pumped" system. The amount of heat that is absorbed
at the primary coil is dependent on the rate of boil-off of the
refrigerant. This is a function of "setting" the condensing
saturation line at a temperature/pressure set-point to facilitate
boil-off of refrigerant at a rate that is commensurate with the
available heat and moisture content in the air stream that is in
thermal communication with the evaporator.
[0057] The boil-off temperature set point (condensing line) is set
at the primary condenser. The primary pre-cooler evaporator circuit
is capable of cooling the high latent air down (intake air) to
within approximately 2 degrees of the false atmosphere wet bulb in
the chamber. This is accomplished by circulating refrigerant that
is within 1-1/12.degree. F. below the leaving air temperature
set-point.
[0058] The leaving air temperature can be further reduced, by
enabling the compressor circuit on the secondary pre-cooler
evaporator to operate. The compressor circuit further absorbs the
heat that is present at intake air as it passes through the
secondary pre-cooler evaporator. The leaving air temperature is
regulated by the operating controls of the compressor circuit at a
demand requirement to meet a specific set-point (enthalpy space
condition) that is to be maintained in the evaporative heat
rejection chamber. By maintaining a low set-point temperature in
the heat rejection, three significant efficiency gains are
accomplished. The first is that it enables colder process water to
be produced, which in turn enables high efficiency gains on the
process water equipment, (load side). The second is that it
produces cooler condenser water fluid which in turn can be used to
set lower condenser set-points (refrigerant boil-off) at the
primary pumped refrigerant circuit condensers. Third, is that it
facilitates lower compression lift ratios to enable lower kw/ton
energy ratios on the secondary pre- and after-cooler refrigerant
compression circuits.
[0059] The in-series pumped refrigerant evaporators and heat
rejection cycle enable a cascading effect in energy use
effectiveness. By creating a lower atmosphere, the cycle creates an
environment that is conducive to facilitating low-lift energy
efficiency on both the system load compressors, as well as the
compression on the secondary trim cycles.
[0060] The secondary evaporator circuit has similar operational
characteristics at the primary circuit by utilizing a pumped
refrigerant to deliver the fluid to the evaporator. However, the
secondary circuit also has a compression circuit (refrigerant to
refrigerant) to facilitate a further reduction in the inlet air
temperature and moisture removal processes. The effective load on
the secondary compressor is significantly reduced because much of
the heat load has already been rejected at the primary evaporator
coil circuit without the need for mechanical compression.
[0061] A pumped water cooled condenser cycle is in series with the
cold water basin collection pan, the air stream (spray nozzles),
and the water cooled condenser to reject the heat from the
evaporator coils that are in the air stream. The apparatus can vary
its water production, water reclaim, and interior chamber enthalpy
dependant on load requirements, environmental conditions, and a
particular desire to operate as a free cooler, or a combination of
operating modes.
[0062] Reference will now be made in detail to embodiments of the
present disclosure. While certain embodiments of the present
disclosure will be described, it will be understood that it is not
intended to limit the embodiments of the present disclosure to
those described embodiments. To the contrary, reference to
embodiments of the present disclosure is intended to cover
alternatives, modifications, and equivalents as may be included
within the spirit and scope of the embodiments of the present
disclosure as defined by the appended claims.
[0063] More particularly, referring to FIGS. 1-5, a liquid
refrigerant-assisted evaporative cooling system 100 is presented
according to an exemplary embodiment of the present disclosure. A
cooling tower or fluid cooler 102 is described in more detail
below. It is noted that cross-flow and counter-flow air pattern
arrangements place inlets and outlets at opposite ends of the
cycle. The flow of inlet air 10 passes through an intake, as
indicated by arrow 10. The air 10 passes through and is in thermal
communication with a primary pre-cooler evaporator 331, the air 20
is partially cooled and a portion of moisture from the air 20 (Q4)
is removed. The air 20 continues and passes through and is in
thermal communication with a secondary pre-cooler evaporator 332.
Thus, further cooling and moisture removal (Q5) is accomplished.
The air 30 enters the heat rejection chamber 304 where it is in
thermal communication with the water film 120a (QRC), (or water 300
for Fluid Cooler, as shown in FIG. 3) that is cascading down the
fill 105. The cold air 30 is in thermal communication with the
water film 120a and the evaporative heat rejection process thus
takes place. The latent heat from the process water 120a is
absorbed into the air 40. The remaining process water 120a that has
not evaporated, is cooled by the evaporative process and cascades
down the fill 105 and is collected in the cold water basin 350.
[0064] The basin cold water 300 is discharged out of the cold water
basin 350 by the system load header pump 2100. The fluid 120b is
circulated through the process water system 50 to continue the heat
rejection cycle. The warm latent air 40 enters the fan(s) 310, and
it is discharged out into the atmosphere, as shown in FIG. 1, or
enters into thermal communication with the after-cooler evaporator
circuits 333 and 334, as shown in FIG. 2. After-cooler evaporator
cycles 333 and 334 are in thermal communication with the entering
air 40, in advance of discharge to the atmosphere or to be utilized
for conditioned cooling air 40, or enter a face and bypass air
cycle chamber 600, as illustrated in FIG. 4.
[0065] The control and monitoring of the air 10-80 through its
various steps of pre-cooling, heat absorption and after-cooling is
accomplished via thermal enthalpy temperature sensors T1-T7. The
sensors monitor and regulate the various refrigerant cycles in
order to maintain desired space temperature and moisture content in
the air stream at the various thermal communication heat
exchanges.
[0066] If after-cooler circuit evaporators 333 and 334 are present
they may be fed from the same cycles 2001 and 4001 that serve the
pre-cooler evaporators 331 and 332, or they may be fed from
alternative cycles if the combined load requirements of the
pre-cooler and after-cooler cycles are too great for a single
circuit to handle on its own.
[0067] If after-coolers 333, 334 are present, and a water reclaim
cycle is initiated, the latent air 40 enters and is in thermal
communication with the primary after-cooler evaporator 333. The air
40 is partially cooled and a portion of moisture is recovered (Q6)
from the air 50. The desired temperature set point for the leaving
air 50 off of the primary after-cooler evaporator is regulated by
the temperature sensor T5. T5 is located in the air stream between
primary after-cooler evaporator 333 and the secondary after-cooler
334.
[0068] If there is a desire to further reclaim moisture or cool the
outlet air 50, the air 50 may be in thermal communication with the
after-cooler evaporator 334. The air 50 can be further partially
cooled and additional water recovery (Q7) can be accomplished at
this heat exchange.
[0069] The cold air 60 which has now been fully after-cooled, and a
portion of desired moisture has been extracted, (Q7) continues to
be circulated through the cycle.
[0070] The cold air 60 continues and can be discharged to the
atmosphere 10, or a portion of the cold air 60 can enter the face
and bypass air cycle 600, as shown in FIG. 4.
[0071] In FIG. 4, a portion of the air 60 exits the apparatus
through a discharge spill air damper 610. The balance of the
regulated cold air 60 enters into a bypass duct 620. The volume or
portion of the air 60 that is allowed to enter into the 620 bypass
duct is limited or regulated through a bypass damper 630.
[0072] The bypass air 60 enters into a mixing air chamber 70. The
air 60 is in thermal communication (Q8), with the intake air 10.
The blended air 15 facilitates a decrease in heat load on the
primary air 10 that enters the primary pre-cooler evaporator
331.
[0073] Liquid refrigerant assist cycles 2001 and 4001 are included
within the cooling tower 102 within a first or lower section 102a
of the cooling tower 102 that functions as a Cooling Distribution
Unit (CDU). Those skilled in the art will recognize that the CDU
within the first or lower section 102a may also be configured as a
stand-alone CDU.
[0074] More particularly, via cooling water return header pump
2100, the now cooled cooling water supply from the heat load 50,
representing the transfer of heat (Q.sub.0) to the cooling water
supply header 120a on the suction side of the cooling water supply
header pump 2100, is in fluidic communication with the cooling
water supply header pump 2100. The cooling water supply discharges
from the cold water basin 350, supplying cold water to the header
pump 2100. The cold process water 120b is used to facilitate heat
rejection in the load system 50. The load process water return 120a
is returned to the cooling tower 102 to enable heat rejection to
occur. The fluid return 120a is distributed to a hot deck water
basin 103, where it passes through basin water nozzles 104. The
fluid return 120a drizzles down through flow distribution nozzles
104 and creates a water film on the interior chamber plastic fill
or wicking material 105 where it is in thermal contact with the
pre-cooled air 30 that is present in the air chamber 304.
[0075] The fluid 120a flowing over the wicking fill 105 is in
thermal communication with the pre-cooled air 30, which has now
been cooled by pre-cooling evaporators 331 and 332, respectively.
The evaporative process takes place in the chamber 304, as
illustrated in FIG. 1, by the transfer of heat (Q.sub.RC) from the
water evaporation process in contact with the fluid 120a.
[0076] Thus, the heat load (Q.sub.0) at 50 is in thermal and
fluidic communication with the evaporative recirculation cooling
cycle via cooling water (or refrigerant or process fluid) supply
header 120b.
[0077] The evaporative recirculation cooling cycle includes one or
more circulation fans 310 and also first and second spray nozzle
headers 121a and 121b that are in thermal and fluidic communication
with the heat rejection chamber 304.
[0078] As explained in more detail below, due to the pressure of
the water in the spray nozzle headers 121a and 121b, the water
seeks a proper elevation level in the hot deck distribution pan
103, and is distributed to the spray nozzles 104. Within the second
section of the cooling tower 102, an air or a mixture of air and
water spray and water film is circulated across the fill wicking
material 105, via the circulation fan(s) 310 as shown by the
arrows, thus resulting in the transfer of heat (Q.sub.RC) from the
heat rejection load system 50 to the air stream 30 in the heat
rejection chamber 304. The quantity of entering air is regulated by
the fan(s) 310 and is based on enthalpy temperature control through
the various stages of pre-cooling 331 and 332, and or blended
return air 70 and outside air 10.
[0079] In the exemplary embodiment of FIG. 1, the liquid
refrigerant assist cycles 2000 and 4000 are implemented by
providing a first liquid refrigerant assist cycle 2001 and a second
liquid refrigerant assist cycle 4001. The first liquid refrigerant
assist cycle 2001 is dedicated to, and in fluid communication with,
the first evaporation coil 331 while the second liquid refrigerant
assist cycle 4001 is dedicated to, and in fluid communication with,
the second evaporation coil 332. The assist cycles 2001, 4001 may
also be used to serve the after-cooler evaporator circuits 333,
334.
[0080] Accordingly, the first and second evaporation coils 331 and
332 are in thermal and fluid communication with the first and
second liquid refrigerant assist cycles 2001 and 4001 via first
liquid refrigerant assist cycle supply headers 207, 211, 407, 411
and first liquid refrigerant assist cycle return headers 210, 212,
410, 412, respectively.
[0081] As liquid refrigerant is supplied to first evaporation coil
331, and after cooler evaporator 333 via the first liquid
refrigerant assist cycle 2001, supply headers 407, and 411 the
liquid refrigerant is at least partially vaporized by transfer of
heat (Q4 and Q6), from the evaporation coils 331 and 333, such that
at least partially vaporized refrigerant in the form of (i) a gas
or (ii) a gas and liquid refrigerant mixture is returned via liquid
refrigerant assist cycle return header 410, to condenser 400, in
liquid refrigerant assist cycle 4001.
[0082] Within the condenser 400, heat (Q3) is transferred from the
(i) gas or (ii) gas and liquid refrigerant mixture, such that
condensation of the liquid refrigerant occurs within the condenser
400, and liquid refrigerant is discharged to the liquid receiver
402 via supply line 401. The liquid refrigerant receiver 402 is
operated to maintain a supply of liquid refrigerant on the suction
side of liquid refrigerant pump 404, which discharges liquid
refrigerant into the liquid refrigerant assist cycle supply headers
407 and 411 to supply liquid refrigerant to the evaporation coils
331 and 333, respectively.
[0083] In the exemplary embodiment of FIG. 1, the second liquid
refrigerant assist cycle 4001 is dedicated to, and in fluid
communication with, the second pre-cooler evaporation coil 332. The
assist cycles 2001, 4001 may also be used to serve the after-cooler
evaporator circuit evaporator coil 334 should they be desired to do
so, as illustrated in FIGS. 1 and 2.
[0084] Accordingly, the second evaporation coils 332 and 334 are in
thermal and fluid communication with the first liquid refrigerant
assist cycle 2001 via first liquid refrigerant assist cycle supply
headers 207, 211 and first liquid refrigerant assist cycle return
headers 210, 212, respectively.
[0085] As liquid refrigerant is supplied to second evaporation coil
332, and after cooler evaporator 334 via the first liquid
refrigerant assist cycle supply headers 207, and 211 the liquid
refrigerant is at least partially vaporized by transfer of heat (Q5
and Q7), from the secondary evaporation coils 332, 334 such that at
least partially vaporized refrigerant in the form of (i) a gas or
(ii) a gas and liquid refrigerant mixture is returned via liquid
refrigerant assist cycle return headers 210 and 212 to the
evaporator 200, serving liquid refrigerant assist cycles 2001,
4001.
[0086] Within the evaporator 200, heat (Q1), is transferred from
(i) the gas or (ii) the gas and liquid refrigerant mixture such
that condensation of the liquid refrigerant occurs within the
evaporator 200 and liquid refrigerant is discharged via the
evaporator 200 to the liquid receiver via header supply line 201 to
liquid receiver 202. The liquid refrigerant receiver 202 is
operated to maintain a supply of liquid refrigerant on the suction
sides of liquid refrigerant pump 204, which discharges liquid
refrigerant into the liquid refrigerant assist cycle supply headers
207 and 211 to supply liquid refrigerant again to the evaporation
coils 332 and 334, respectively.
[0087] Flow of (i) the gas or (ii) the gas and liquid refrigerant
mixture may be bypassed around the evaporator coils 331-334 by
utilizing bypass valves 206 and 406. A portion of the fluid can be
bypassed directly to the receivers 202 and 402 in order to maintain
a stable level of liquid refrigerant ahead of the refrigerant pumps
204 and 404. The control of the valves 206 and 406 is regulated by
level control sensors 202a and 402a.
[0088] The circulation or flow of a first liquid refrigerant
circuit 2001, from the evaporator 200 to the evaporator coils 332
and 334 via the liquid refrigerant pump 204 and the liquid receiver
202 and back to the condenser evaporator 200 as (i) a gas or (ii) a
gas and liquid refrigerant mixture, respectively, define the first
liquid refrigerant loop.
[0089] The circulation or flow of the second liquid refrigerant
circuit 4001, and from the condenser 400 to the evaporator coils
331 and 333, via the liquid refrigerant pumps 404 and the liquid
receiver 402, and back to the condenser 400, as (i) a gas or (ii) a
gas and liquid refrigerant mixture respectively define first liquid
refrigerant loops.
[0090] The heat flow (Q1) is transferred within the evaporator 200
and from the condensation side represented by the input flow of (i)
gas or (ii) gas and liquid refrigerant mixture in the liquid
refrigerant assist cycle return headers 210, 212 to the liquid
refrigerant assist cycle supply headers 207, 209 to the trim the
evaporation side of the evaporator 200. The trim evaporation side
is represented by the input flow to the evaporators 200 of a second
liquid refrigerant flowing in second liquid refrigerant loop 5001,
as shown in FIG. 2. The trim evaporation side is also represented
by the second liquid refrigerant loop 5001, in which a second
liquid refrigerant is circulated from the evaporators 200 to a
condensers 502 such that the second refrigerant is received in
liquid form from the condensers 502 via second liquid line 503, and
circulated to an expansion device 504, thus enabling evaporation to
occur at evaporator 200.
[0091] The fully evaporated second refrigerant gas is evaporated
via a trimming method, and circulates from the evaporator 200 via
the suction line 506 to a compressor 500, where the compressed gas
is discharged out via line 501 and enters condenser 502. The
refrigerant fully condenses and transfers its heat to the condenser
water circuit 300.
[0092] The compressor 500 compresses the fully evaporated second
refrigerant to a high pressure gas having a pressure range of
approximately 100-115 Pa. The high pressure gas second refrigerant
circulates from the discharge side of compressor 500 to the
condenser side of condenser 502 via compressor discharge to
condenser connection lines 501. Heat (Q5) is transferred from the
condenser side of condenser 500 to water the sides of the condenser
500.
[0093] The refrigerant circuits 2001 and 4001 are fed by a
circulated water cooled condensing circuit 3000 to absorb and
reject the heat that is generated in the pre-cooler, after-cooler,
and system load processes. The condensing circuit 3000 consists of
a cold water supply, a cold water collection basin 350, a supply
distribution pipe 353, a circulating pump 352, supply headers 353,
354, serving condensers 400, 502 respectively, return header 355,
and connections to spray distribution headers at cooling towers
121a and 122a, as shown in FIGS. 1 and 2, or spray nozzles 1000 at
fluid cooler, as shown in FIG. 3.
[0094] The cold water (approximately 65.degree. F.) 300 that has
been collected and has completed the evaporation cycle, is in
thermal contact with the cold air stream 30. The cold water 300 is
collected and present in the cold water basin 350. The cold water
300 is circulated out of the discharge of the cold water basin 350,
via discharge line 352. The cold water 300 is circulated via cold
supply water header 353. The cold water 300 enters and is in
thermal contact with condenser 400.
[0095] The heat of the second refrigerant circuit 4001 is then
exchanged (Q3). The warmer condenser water 300 (approximately
71.degree. F.) exits the condenser via condenser discharge line
354. The warmer condenser water 300 enters and is in thermal
contact with condenser 502. The heat of the circuit 2001 is then
exchanged (Q2). The hot water (approx. 80.degree. F.) exits
condenser 502. It is circulated via return water header 355. The
hot water enters the spray distribution headers 121a and 122a,
where it blends with the system load return water 120a. The hot
water collects in the hot deck water basins 103, and is distributed
down through the flow distribution nozzles 104. The water 120a
cascades down through the fill or wicking media 105 where it is in
fluidic thermal contact with the cold air stream 40 in the air
chamber. It is noted that the fluid cooler, as shown in FIG. 3, is
a closed circuit. Therefore, the cascading water is in fluidic
thermal contact with the load system heat rejection coil 105a, as
shown in FIG. 3.
[0096] Additionally moisture can be re-captured from the air stream
utilizing the after-cooler evaporators 333 and 334, respectively.
The level of moisture elimination and additional cooling (Q6 and
Q7) can be regulated by the enthalpy temperature sensors T5 and T6
located in the air stream after their respective evaporator coils
333 and 334. Since the cooling tower or fluid cooler 102 can
process fresh water in advance of the cycle, or after-cool and
re-claim additional moisture from the air stream, the circuit has
been fitted with water collection channels 600 and 601,
respectively, as shown in FIGS. 2 and 3. The channels can be used
to collect the potable water and direct it to the cold water basin
sump 350, or can forward it to a water collection tank or
system.
[0097] By lowering the temperature at primary evaporator coil 331
by increasing the heat transfer (Q4), and further lowering the
temperature below the dew point of the air flowing in the direction
of arrow B at secondary evaporator coil 332, Q5, pure water can be
processed from the air stream, and drips down from evaporator coil
331 and/or evaporator coil 332, and collects as potable water in
water collection channels 600 and 601, as shown in FIGS. 2 and 3.
The potable water can be delivered to the cold-water basin 350, or
it can be redirected to an alternative water collection device or
system.
[0098] The temperature of the load system water, or the cold
condenser basin water, is mixed with the load system water (cooling
tower), or sprayed directly at the spray water nozzles. Water
nozzle headers 3200 (see FIG. 3) range from approximately
65.degree. F. to approximately 76.degree. F. The water in the cold
water basin 350 provides suction head to spray water pump 352,
which pumps spray water 352, to and through the water side of
condensers 502 and 400, via cold water basin to condenser
connection lines 353. The water 300 absorbs the heat (Q2 and Q3)
that is rejected from the primary evaporator process and the trim
circuit compressors via heat transfer within the condensers 400 and
502, respectively.
[0099] The cool water, which is generally approximately 6-7 degrees
.degree. F. hotter at the outlet side of condenser 400
(71-72.degree. F.) and additionally 6-7 degrees hotter at the
outlet side of condenser 502 (78-79.degree. F.), is then circulated
to the system load 210 spray nozzles headers 121a and 122a (Cooling
Tower) or fed directly to the spray nozzles 3200 (Fluid Cooler),
see FIG. 3. The 120a water (or water 300) drizzles down the fill
(or heat rejection coil) and is in thermal communication with the
cold air stream 30. The water that does not evaporate is cooled and
drops to the lower cold water basin 350. The condenser water 300
supply would range from about approximately 60.degree. F. to about
approximately 80.degree. F. This is dependent on the level of
pre-cooling of the atmosphere that takes place at the pre-cooler
evaporators 331 and 332.
[0100] As shown in FIG. 4, the flow of the cool discharge air 60
can be controlled by the set of dampers 610, bypass 630, and intake
650. This cool or tempered air is a by-product of the after-cooler
evaporation process occurring at evaporator coils 333, 334. The
temperature of the air 60 is controlled by temperature sensors T4
and T5 located in the air stream immediately following the
discharge of after-cooler evaporators 333 and 334, respectively.
The discharge air 60 temperature is regulated from approximately
55.degree. F. to 60.degree. F. when used for external cycle HVAC or
process cooling air.
[0101] A face and bypass duct arrangement as depicted in FIG. 5
includes modulating intake air dampers 650, spill air dampers 610,
and bypass air dampers 630. This air bypass circuit 600 enables
further energy savings to the cycle by pre-treating a portion of
the inlet air 10 with a portion of cold discharge air 60. The air
is blended at the inlet-mixing chamber 70. This air bypass
facilitates a reduction in load capacity (Q7) on the primary and
secondary pre-cooler evaporator circuits 331 and 332,
respectively.
[0102] The electrical power that is consumed in the evaporative
process to pre-treat the air, and create a false atmosphere, is
less than the power that the cycle saves on the system load side.
By pre-cooling the atmosphere, the cycle facilitates a reduction of
total combined power of the system to approximately 30%-40%, versus
the power that would have been consumed if the normal atmosphere
were in contact with the load system at the heat rejection
process.
[0103] Because the condenser water 120b is significantly cooled by
the pre-cooling and evaporation process in the chamber 304, the
refrigerant fluid of the primary circuit is able to set a very low
condensing point without any mechanical compression assistance. The
primary refrigerant circuit 2001 is thereby able to absorb
approximately 66 percent of the latent and sensible heat loads from
the entering air 10 without compression assistance. The work of
this initial heat rejection cycle 2002 is performed by a minimal
horsepower refrigerant pump 256 (3-5 horsepower), which requires
less than 5% of the power that would have ordinarily been required
by a refrigerant DX compressor.
[0104] A 66%-75% reduced DX compression circuit 4001 can handle the
resultant load that remains on the inlet air stream 20. However,
the actual kw/ton that the compressor 500 can operate at is
significantly reduced because the system lift has been reduced by
closer tolerance suction and discharge operating pressures. As a
result, the entering condenser water has experienced a temperature
reduction. The delta temperature span of the inlet condenser water
300 (approximately 71.degree. F.) versus the leaving pumped
refrigerant 253 (approximately 64.degree. F.) is only approximately
7.degree. F. This delta between the inlet hot side fluid and the
outlet cold side fluid enables a low lift condition for the
compressor to operate under. This allows for a kw/ton of
approximately 0.20 kw/ton, which is about 25% of the normal
required kw/ton of a compressor circuit operating in a "normal"
high lift atmosphere.
[0105] In addition to the energy benefits, the cycle facilitates
initial water capture through the air stream in thermal contact
with the pre-cooler evaporator 331 and 332, respectively. The cycle
may also recapture all, or a portion of the moisture that has been
evaporated into the air stream 40 following the heat rejection
process of the base system load 50.
[0106] The evaporative cooling system, as represented in FIG. 3, is
similar to the evaporative process depicted in FIGS. 1 and 2.
However, the fluid cooler circuits have a closed circuit
evaporative heat rejection process versus the atmosphere cycle that
is indicative of cooling towers.
[0107] The following description illustrates the differences in the
fluid cooler circuits. The fluid cooler has a fluid in thermal and
fluidic communication with a generalized heat load 50 via a cooling
water return (or refrigerant or any other process cooling fluid)
header 120a from the heat load 50 and a cooling water (or
refrigerant) supply header 120b. For the purposes of illustration
herein, the return header 120a and the supply header 120b are
described herein as cooling water return header 120a and cooling
water supply header 120b. Although, a refrigerant or any other
process cooling fluid may flow through the headers 120a and 120b to
transfer heat from the heat load 50.
[0108] The evaporative heat process takes place with the water 102a
in thermal communication (QRC) and contact time with the fluid
cooler heat rejection coil 105a. The evaporative cooling system has
a fluid 102b in thermal and fluidic communication with a
generalized heat load 50 via a cooling water return (or refrigerant
or any other process cooling fluid) header 120a from the heat load
50 and a cooling water (or refrigerant) supply header 120b. For
illustration purposes, the return header 120a and the supply header
120b are described herein as cooling water return header 120a and
cooling water supply header 120b. Although, a refrigerant or any
other process cooling fluid may flow through the headers 120a and
120b to transfer heat from the heat load 50. The evaporative heat
process takes place with the water 120a in thermal communication
and contact time with the fluid cooler internal heat rejection coil
105a.
[0109] FIG. 3 pertains to closed circuit fluid coolers which have
by nature a closed circuit coil 105a to facilitate the evaporative
heat absorption process versus an open cooling tower system, as
depicted in FIGS. 1 and 2. The heat that is evaporated and rejected
in the fluid cooler cycles occurs when the condenser water fluid is
sprayed and drizzled over the heat load rejection coil, where heat
from the load is rejected into the atmosphere chamber 304. The warm
latent air 40 is then circulated up to the after-cooler evaporators
333, and 334, respectively, (if present) and the process is similar
to the cooling tower cycles previously depicted in FIG. 2.
[0110] In summary, an evaporative cooling cycle that can
efficiently produce its own water without expending additional
power is presented. Also, a water production and reclaim cycle that
can efficiently produce its own water and recover additional
moisture that would normally escape into the atmosphere is
presented. The exemplary embodiments further describe a water
production and recovery cycle that can be retrofitted onto existing
cooling towers and fluid coolers enabling them to become water
production and recovery equipment. The exemplary embodiments of the
present disclosure further describe an efficient cooling cycle that
enables heat rejection apparatuses to assist in greater system
efficiency gains by producing colder process water than what the
environment would normally facilitate at a net savings in power
use.
[0111] The exemplary embodiments of the present disclosure further
describe a three-stage in series cooling and heat rejection cycle
that enables the primary evaporator process to gain higher and more
efficient heat rejection capabilities as a result of being in an
in-series process with the secondary evaporator and the ultimate
evaporative water heat rejection process. The three-stage in series
cooling and heat rejection cycle enables the secondary evaporator
process to gain more efficient heat rejection capabilities as a
result of being in an in-series process with the primary evaporator
and the ultimate evaporative heat rejection process. Moreover, the
three-stage in series cooling and heat rejection cycle enables the
production of colder process water because it is in series with a
primary and secondary evaporator process. Additionally, the
three-stage in series process cycle can be adapted to include two
additional efficient stages of water recovery and cooling
production.
[0112] The exemplary embodiments of the present disclosure further
disclose a three-stage in-series cycle that can produce its own
water, produce a false atmosphere with very little energy expended,
recapture moisture form the air stream, and produce cool
conditioned air. The three-stage evaporative heat rejection cycle
enables a reduction in the need for outside water sources and
produces good quality potable makeup water which significantly
reduces water losses due to excessive blow down requirements.
Moreover, the three-stage evaporative heat rejection cycle
significantly reduces chemical blow-down effluents into the
environment and the sewage support structure.
[0113] Persons skilled in the art will understand that the devices
and methods specifically described herein and illustrated in the
accompanying drawings are non-limiting exemplary embodiments. The
features illustrated or described in connection with one exemplary
embodiment may be combined with the features of other embodiments.
Such modifications and variations are intended to be included
within the scope of the present disclosure. As well, one skilled in
the art will appreciate further features and advantages of the
present disclosure based on the above-described embodiments.
Accordingly, the present disclosure is not to be limited by what
has been particularly shown and described, except as indicated by
the appended claims.
[0114] It should be understood that the foregoing description is
only illustrative of the present disclosure. Various alternatives
and modifications can be devised by those skilled in the art
without departing from the disclosure. Accordingly, the present
disclosure is intended to embrace all such alternatives,
modifications and variances. The embodiments described with
reference to the attached drawing figs. are presented only to
demonstrate certain examples of the disclosure. Other elements,
steps, methods and techniques that are insubstantially different
from those described above and/or in the appended claims are also
intended to be within the scope of the disclosure.
* * * * *