(12)
`
`United States Patent
`Pierson
`
`(10) Patent N0.:
`(45) Date of Patent:
`
`US 6,470,686 B2
`Oct. 29, 2002
`
`US006470686B2
`
`(54) SYSTEM FOR CHILLING INLET AIR FOR
`GAS TURBINES
`
`5,632,148 A * 5/1997 Bronicki et a1. ............ .. 60/728
`5,758,502 A * 6/1998 Utamura .................... .. 60/728
`
`(76) Inventor: Tom L. Pierson, 7910 Arbor Hill Ct.,
`Sugarland, TX (US) 77479
`
`( * ) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 0 days.
`
`(21) Appl, No; 09/961,711
`_
`(22) Filed:
`(65)
`
`Sep. 24, 2001
`Prior Publication Data
`
`Us 2002/0017095 A1 Feb‘ 14’ 2002
`,
`,
`Related U'S' Apphcatlon Data
`.
`.
`.
`.
`(63) fggngmr‘fgfflga‘tf £1155 hgétignolgg' O9/369’788’ ?led OnAug' 6’
`7
`7
`7
`7
`(51) Int. Cl. ................................................ .. F02C 3/ 00
`U-S- Cl- .......................................... ..
`(58) Field of Search ................... .. 60/772, 728; 62/175,
`62/332
`
`(56)
`
`_
`References Clted
`
`US. PATENT DOCUMENTS
`
`OTHER PUBLICATIONS
`Ondryas, et al., “Options in Gas Turbine Power Augmenta
`tion Using Inlet Air Chilling,” presented at the Gas Turbine
`and Aeroengine Congress and Exposition, Jun. 11—14, 1990,
`Brussels, Belgium.
`* Cited by examiner
`
`Primary Examiner—Ehud Gartenberg
`(74) Attorney, Agent, or Firm—Moser, Patterson &
`Sheridan, LLP
`(57)
`
`ABSTRACT
`
`In a gas turbine poWer plant system having an air chiller for
`loWering the temperature of inlet air, a compressor for
`compressing the inlet air, a combustor for combusting the
`compressed air and fuel and a poWer turbine for providing
`useful poWer, a method and apparatus for chilling Water
`delivered to the air chiller is provided, having a thermal
`Water Storage tank for Storing Chilling Water, the tank having
`a bottom portion and a top portion, and a bottom inlet and
`a bottom outlet and a top inlet and a top outlet. A charge
`cycle is provided Wherein the tank is ?lled With chilled
`Water, and a discharge cycle is provided Wherein the chilled
`Water is fed to the air chiller, thereby chilling the inlet air to
`the poWer turbine.
`
`1,781,541 A * 11/1930 Einstein ..................... .. 62/110
`
`11 Claims, 3 Drawing Sheets
`
`PAGE 1 of 13
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`PETITIONER'S EXHIBIT 1306
`
`

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`PAGE 2 of 13
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`PETITIONER'S EXHIBIT 1306
`
`

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`PAGE 3 of 13
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`PETITIONER'S EXHIBIT 1306
`
`

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`U.S. Patent
`
`0a. 29, 2002
`
`Sheet 3 of3
`
`US 6,470,686 B2
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`PAGE 4 of 13
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`PETITIONER'S EXHIBIT 1306
`
`

`
`US 6,470,686 B2
`
`1
`SYSTEM FOR CHILLING INLET AIR FOR
`GAS TURBINES
`
`This is a continuation of application Ser. No. 09/369,788
`?led on Aug. 6, 1999 now US. Pat. No. 6,318,065.
`
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`This invention relates broadly to cooling inlet air to a gas
`turbine. In a speci?c embodiment, the invention relates to an
`apparatus and method for storing Water in a thermal storage
`tank, and using the stored Water to cool the inlet air to a gas
`turbine,
`2. Description of the Related Art
`A conventional gas turbine system includes: an air com
`pressor for compressing the turbine inlet air; a combustion
`chamber for mixing the compressed air With fuel and
`combusting the mixture, thereby producing a combustion
`gas; and a poWer turbine that is driven by the combustion
`gas, thereby producing an exhaust gas and useful poWer.
`Over the years, various technologies have been employed
`to increase the amount of useful poWer that the poWer
`turbine is able to produce. One Way of increasing the poWer
`output of a gas turbine is to cool the turbine inlet air prior to
`compressing it in the compressor. Cooling causes the air to
`have a higher density, thereby creating a higher mass ?oW
`rate through the turbine. The higher the mass ?oW rate
`through the turbine, the more poWer the turbine produces.
`Cooling the turbine inlet air temperature also increases the
`turbine’s ef?ciency.
`Various systems have been devised for chilling the inlet
`air to the compressor. One such system uses evaporative
`cooling, Wherein ambient temperature Water is run over
`plates or over a cellular media inside of a chamber, thereby
`creating thin ?lms of Water on each plate, or on the media.
`The turbine inlet air is then draWn through the chamber, and
`through evaporative cooling, the air is cooled to near the Wet
`bulb temperature. This system is limited to cooling the air to
`the Wet bulb temperature, Which is dependent upon the
`atmospheric conditions at any given time. Another system
`uses a chiller to chill Water that is then run through a coil.
`The inlet air is then draWn through the coil to cool the air.
`This system requires parasitic poWer or steam to drive the
`chilling system Which has the further draWback that When
`inlet air cooling is needed the most, ie during the day When
`the temperature is the highest, is also the time When poWer
`demand from the turbine is the highest, ie during the day
`When poWer users are in operation. In order to run the chiller,
`poWer from the turbine is required, but this poWer is needed
`by the users of the turbines poWer. On the other hand, When
`cooling is needed the least, ie at night When the tempera
`tures are the loWest, surplus poWer from the turbine is
`available because the consumers of the turbine’s poWer are
`largely not in operation. Accordingly, a continuing need
`exists for a turbine inlet air cooling system Which: Would
`ef?ciently cool turbine inlet air; Would take advantage of
`surplus poWer available during times of loW consumer
`poWer demand; and Would not drain the system of poWer
`during times of high consumer poWer demand.
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`SUMMARY OF THE INVENTION
`
`The claimed invention may be directed to a method for
`chilling inlet air to a gas turbine poWer plant, Which may
`include: providing a system of circulating chilling Water
`including a chilling system; providing an inlet air chiller for
`
`65
`
`2
`loWering the temperature of the inlet air being fed to a gas
`turbine compressor through heat transfer betWeen the cir
`culating chilling Water and the inlet air, providing a thermal
`Water storage tank Which is operably connected to the
`system of circulating chilling Water, the thermal Water
`storage tank containing chilling Water having a bottom;
`during a charge cycle, removing a ?rst portion of chilling
`Water from the thermal Water storage tank, passing the
`removed ?rst portion of Water through the chilling system to
`loWer the temperature of the removed ?rst portion of Water
`and to provide a chilled removed ?rst portion of Water, and
`then introducing the chilled removed ?rst portion of Water
`into the thermal Water storage tank at a point proximate the
`bottom of the tank, Wherein the chilled removed ?rst portion
`of Water is introduced to the tank in an amount suf?cient to
`loWer the average temperature of the chilling Water in the
`thermal Water storage tank; and during a discharge cycle,
`chilling the inlet air by removing a second portion of chilling
`Water from the thermal Water storage tank, from a point
`proximate the bottom of the tank and then passing the
`second portion of chilling Water to the inlet air chiller to
`make heat transfer contact betWeen the second portion of
`chilling Water and the inlet air, such that the temperature of
`the inlet air is loWered.
`In one speci?c embodiment of the claimed method, the
`average temperature of the chilling Water in the tank may be
`loWered to about 33° F. to about 40° F. during the charge
`cycle and may be raised to about 60° F. to about 70° F.
`during the discharge cycle. In another speci?c embodiment,
`the times of the charge and discharge cycles may be such
`that, before the temperture of the chilling Water proximate
`the bottom of the tank reaches about 36° F. during the
`discharge cycle, the charge cycle is initiated. In another
`speci?c embodiment of the method for chilling inlet air, the
`?rst portion of chilling Water removed from the thermal
`Water storage tank during the charge cycle may be removed
`through a top outlet. In yet another speci?c embodiment, the
`second portion of chilling Water removed from the thermal
`Water storage tank during the charge cycle may be removed
`through a bottom inlet. In yet another speci?c embodiment,
`the chilling Water in the tank may have an average tempera
`ture that can be loWered during the charge cycle and raised
`during the discharge cycle. In a further speci?c embodiment
`of the claimed method, the discharge cycle may be carried
`out during the night-time and the charge cycle may be
`carried out during the day-time. In still another speci?c
`embodiment, the Water level in the tank may remain sub
`stantially constant during the charge and discharge cycles. In
`still a further speci?c embodiment, the one or more chillers
`may be deactivated during the discharge cycle. In another
`speci?c embodiment, the discharge cycle may occur during
`peak poWer usage of the gas turbine poWer plant. In another
`speci?c embodiment, the discharge cycle may be performed
`after the removing of at least a portion of the volume of
`chilling Water from the thermal Water storage tank during the
`charge cycle, such that the chilled removed Water that is
`introduced into the thermal Water storage tank at a point
`proximate the bottom of the tank may remain substantially
`at the point proximate the bottom of the tank. In another
`speci?c embodiment, the ?rst portion of chilling Water
`removed during the charge cycle may be suf?cient to chill
`substantially all of the Water in the thermal Water storage
`tank to a temperature beloW the temperature of maximum
`Water density. In yet another speci?c embodiment of the
`claimed method, the second portion of chilling Water
`removed during the discharge cycle may be substantially all
`of the chilling Water in the tank. In a further speci?c
`
`PAGE 5 of 13
`
`PETITIONER'S EXHIBIT 1306
`
`

`
`US 6,470,686 B2
`
`3
`embodiment of the method of the present invention, the
`thermal Water storage tank contains a volume of chilling
`Water that is suf?cient to loWer the temperature of the inlet
`air to a range of from about 45° F. to about 55° F. for a period
`of betWeen about 4 hours to about 12 hours.
`The present invention is also directed to a method of
`chilling Water delivered to the air chiller in a gas turbine
`poWer plant system having at least one air chiller for
`loWering the temperature of inlet air, at least one air com
`pressor for compressing the inlet air, at least one combustor
`for burning the compressed air and providing combustion
`gas, and at least one poWer turbine driven by the combustion
`gas for producing useful poWer, a method of chilling Water
`delivered to the air chiller, the method including the steps of:
`providing the at least one air chiller With an air chiller inlet
`that may receive Water, and an air chiller outlet that may
`eXpel Water; providing a thermal Water storage tank, having
`a bottom portion, a top portion, at least one bottom opening
`proximate the bottom portion and at least one top opening
`proximate the top portion, and containing a volume of stored
`Water having an average temperature, and temperature of
`maXimum Water density; performing a charge cycle, by
`introducing through the at least one bottom opening a ?rst
`quantity of chilled Water Which has a chilled Water tempera
`ture that is beloW the temperature of maXimum Water
`density, thereby loWering the average temperature of the
`volume of stored Water, Wherein the ?rst quantity of chilled
`Water being introduced through the bottom opening is suf
`?cient to loWer the average temperature of the volume of
`stored Water to a temperature that is beloW the temperature
`of maXimum Water density; and performing a discharge
`cycle by removing a second quantity of chilled Water from
`the tank through the at least one bottom opening and passing
`the second quantity of chilled Water to the air chiller inlet,
`to loWer the temperature of the inlet air, thereby raising the
`temperature of the second quantity of chilled Water and
`providing high temperature Water, then introducing the high
`temperature Water to the at least one top opening in the tank.
`In one speci?c embodiment of the method of chilling
`Water, the temperature of maXimum Water density may be
`about 392° F. In another speci?c embodiment, the tempera
`ture of the stored Water may have a temperature of from
`about 34° F. to about 40° F. In yet another speci?c embodi
`ment of the claimed method the temperature of the stored
`Water may have a temperature corresponding to the maXi
`mum Water density of about 392° F. In another speci?c
`embodiment sodium nitrate may be added to depress the
`freeZing temperature of the Water thereby alloWing stored
`Water to be in the range of about 25° F. to about 34° F. In
`another speci?c embodiment of the method of the present
`invention, the useful poWer produced by the poWer turbine
`may be consumed at a variable rate, and the charge cycle
`may be performed When the rate is at a minimum. In a
`further speci?c embodiment, the useful poWer produced by
`the poWer turbine may be consumed at a variable rate, and
`the discharge cycle may be performed When the rate is at a
`maXimum. In yet another speci?c embodiment of the
`method of the present invention, the quantity of Water
`eXpelled during the discharge cycle may be less than the
`volume of stored Water. In a further speci?c embodiment,
`the quantity of chilled Water may be chilled by passing Water
`through at least one chiller. In still another speci?c embodi
`ment of the claimed method, the temperature of inlet air may
`be loWered from a high temperature of from about 85° F. to
`about 95° F. to a loW temperature of from about 45° F. to
`about 55° F. In still a further speci?c embodiment, the high
`temperature may be about 90° F. and the loW temperature
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`may be about 50° F. In yet another speci?c embodiment, the
`output of the gas turbine poWer plant system may be from
`about 50 megaWatts to about 250 megaWatts.
`The present invention is also directed to a gas turbine
`poWer plant system, Wherein the system includes: one or
`more air chillers for loWering the temperature of inlet air;
`one or more air compressors for compressing the inlet air;
`one or more combustors for burning the compressed air and
`providing combustion gas; and one or more poWer turbines
`driven by the combustion gas for producing useful poWer,
`and an improvement that may include: a thermal Water
`storage tank for containing chilled Water, Wherein the ther
`mal Water storage tank has a bottom portion With a bottom
`outlet and a top portion, and the tank is operably connected
`to the air chiller such that the chilled Water passes from the
`bottom outlet to the air chiller to loWer the temperature of
`the inlet air and is returned to the thermal Water storage tank;
`and a Water chilling system for chilling the Water in the
`thermal Water storage tank, Wherein the Water chilling
`system is con?gured to receive high temperature Water from
`the top portion of the tank, and Wherein the system is
`con?gured to introduce loW temperature Water to the bottom
`portion of the tank, such that the average temperature of the
`Water in the tank is loWered; and Wherein the Water chilling
`system includes one or more chillers for loWering the
`temperature of the high temperature Water from the top
`portion of the tank to provide loW temperature Water.
`In one speci?c embodiment of the claimed gas turbine
`poWer plant system, the thermal Water storage tank may
`have a bottom, and the bottom outlet may be positioned at
`a height that is less than about 10 feet from the bottom of the
`tank. In another speci?c embodiment of the gas turbine
`poWer plant system, the thermal Water storage tank may
`have a bottom, and the bottom outlet may be positioned at
`a height that is less than about 5 feet from the bottom of the
`tank. In another speci?c embodiment, the thermal Water
`storage tank may have a bottom, and the bottom outlet may
`be positioned at a height that is less than about 18 inches
`from the bottom of the tank. In another speci?c embodiment,
`the tank may have a top outlet and a bottom inlet such that,
`in a charge cycle the high temperature Water may be
`removed through the top outlet and may be fed to the one or
`more chillers, and the loW temperature Water may be intro
`duced to the tank through the bottom inlet. In a further
`speci?c embodiment of the gas turbine poWer plant system,
`the tank may have a bottom outlet such that, in a discharge
`cycle, chilling Water may be removed from the tank through
`the bottom outlet. In still a further speci?c embodiment of
`the gas turbine poWer plant system, the tank may have a
`bottom outlet such that, in a discharge cycle, chilling Water
`may be removed from the tank through the bottom outlet,
`fed to the air chiller and is returned to the tank, bypassing the
`one or more chillers of the Water chilling system. In still a
`further speci?c embodiment of the gas turbine poWer plant
`system, the top portion may be separated from the bottom
`portion by a thermocline. In yet another speci?c
`embodiment, during the charge cycle, the bottom inlet may
`receive a quantity of chilled Water that is sufficient to supply
`the air chiller With Water having a temperature beloW the
`temperature of maXimum Water density for four or more
`hours. In another speci?c embodiment, during the charge
`cycle, the bottom inlet may receive a quantity of chilled
`Water that is suf?cient to supply the air chiller With Water
`having a temperature beloW the temperature of maXimum
`Water density for eight or more hours. In still another
`embodiment, during the charge cycle, the bottom inlet may
`receive a quantity of chilled Water that is sufficient to supply
`
`PAGE 6 of 13
`
`PETITIONER'S EXHIBIT 1306
`
`

`
`US 6,470,686 B2
`
`5
`the air chiller With Water having a temperature below the
`temperature of maximum Water density for tWelve or more
`hours. In still another speci?c embodiment, the thermal
`Water tank may have a height of from about 25 feet to about
`70 feet. In yet another speci?c embodiment, the thermal
`Water tank may have a diameter of from about 50 feet to
`about 250 feet. In another speci?c embodiment, the thermal
`Water tank may have a diameter, and a height, and the
`diameter may be greater than the height. In yet another
`speci?c embodiment of the claimed invention, the volume of
`stored Water may be greater than about eight hundred
`thousand gallons. In still a further speci?c embodiment, the
`temperature of the Water in the top portion may be about 15°
`F. to about 35° F. greater than the temperature of the Water
`in the bottom portion. In another speci?c embodiment, the
`thermal Water storage system may include a plurality of
`thermal Water storage tanks, each of the plurality of tanks
`may have a bottom inlet and a bottom outlet, and each of the
`plurality of tanks may have a top inlet and a top outlet. In
`another speci?c embodiment, the bottom inlet may have a
`bottom diffuser, and the top inlet may have a top diffuser,
`Whereby the Water entering the bottom inlet is diffused, and
`the Water entering the top inlet may be diffused. In yet
`another speci?c embodiment, the temperature of the Water in
`the top portion of the tank may have a temperature ranging
`from about 60° F. to about 70° F. In still a further speci?c
`embodiment, the temperature of the Water in the bottom
`portion of the tank may have a temperature that is above the
`freeZing temperature. In another speci?c embodiment, the
`Water chilling system may include at least one mechanical
`chiller. In still another speci?c embodiment of the present
`invention, the Water chilling system may include at least one
`absorption chiller. In still a further speci?c embodiment, the
`Water chilling system may include at least one mechanical
`chiller and at least one absorption chiller. In yet another
`speci?c embodiment, the mechanical chiller may receive
`chilled Water from the absorption chiller, and the mechanical
`chiller may further chills the chilled Water. In another
`speci?c embodiment, the gas turbine poWer plant system
`may additionally including a heat recovery steam generator
`and a steam turbine, Wherein the absorption chiller may be
`driven by steam from the heat recovery steam generator.
`Another speci?c embodiment of the gas turbine poWer plant
`system may additionally include a heat recovery steam
`generator and a steam turbine, Wherein the absorption chiller
`is driven by back pressure from the steam turbine exhaust.
`In another speci?c embodiment, the inlet air may be loWered
`from a ?rst temperature of about from 85° F. to about 95° F.
`to a second temperature of from about 45° F. to about 55° F.
`in the inlet air chiller. In yet another embodiment, the ?rst
`temperature may be about 90° F. and the second temperature
`may be about 50° F. In another speci?c embodiment of the
`gas turbine poWer plant system, the chilling Water being fed
`to the inlet air chiller may have a temperature of from about
`34° F. to about 40° F. In another speci?c embodiment, the
`gas turbine poWer plant system may additionally include a
`steam turbine and a heat recovery steam generator, and the
`heat recovery steam generator may receive exhaust gas from
`the poWer turbine and may provide high pressure steam to
`the steam turbine, and the steam turbine may provide loW
`pressure steam.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`In the draWing:
`FIG. 1 is a schematic diagram of the turbine inlet air
`cooling system of the present invention;
`FIG. 2 is a schematic diagram of an alternative embodi
`ment of the turbine inlet air cooling system of the present
`invention; and
`
`6
`FIG. 3 is a side vieW of a storage tank used in a speci?c
`embodiment of the present invention.
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`
`Speci?c embodiments of the invention Will noW be
`described including a preferred system (apparatus and
`method), referring to attached FIG. 1. All references to the
`“invention” beloW are intended to be directed to the speci?c
`embodiments and not necessarily, in limiting fashion, to the
`broad invention in the claims.
`Generally, referring to FIG. 1, the overall apparatus 10
`includes a conventional gas turbine system 12 having an air
`chiller 14, e.g., a conventional cooling coil, for loWering the
`temperature of inlet air, shoWn schematically by arroW 15a,
`from ambient temperature (T1, e.g., about 90° F. (about 32°
`C.), or in the range of from about 70° F. (about 21° C.) to
`about 85° F. (about 29° C.) to a range of from about 100° F.
`(about 38° C.) to about 115° F. (about 47°
`to provide
`compressor feed air, shoWn schematically by arroW 15b,
`having some loWer temperature (T2, e.g., about 50° F. (about
`10° C.), or in the range of about 45° F. (about 7° C.) to about
`55° F. (about 13°
`The air chiller 14 can be a conven
`tional cooling coil that provides for heat transfer contact,
`e.g., across a set of coils Within the air chiller 14, betWeen
`the circulating chilling Water 16c (preferably at a T3 of about
`34° F. (or about 1° C. to about 2° C.) to about 40° F. (or about
`4° C. to about 5°
`and the inlet air 15a, forming chilled
`compressor feed air 15b, and resulting in a higher tempera
`ture circulating Water 16d (T4, e.g., about 54° F. (about 12°
`C.) to about 60° F. (about 16°
`Apreferred cooling coil
`may be specially circuited so as to achieve relatively high
`changes in the temperature of the Water ?oWing through the
`tubes in the cooling coil. This rise in temperature is prefer
`ably in a range of about 20° F. (about 11° C.) to about 35°
`F. (about 19° C.) on a hot design day. As used herein a
`“design day” is the maximum temperature that the ambient
`air is expected to reach—the temperature upon Which the
`system design is based. The chilled compressor feed air 15b
`may then be introduced to a conventional gas turbine (GT)
`compressor 32, Where it is compressed, combined With fuel
`and burned in a conventional combustor 34 to produce a
`combustion gas that can be used for driving the poWer
`turbine 36, resulting in “exhaust gas.” FIG. 1 shoWs the
`overall system as including only one gas turbine system 12,
`one air chiller 14, one Water chilling system 13, and one tank
`18. HoWever, depending upon system requirements as Well
`as geographical, geological, and other constraints, it may be
`desirable to have more than one gas turbine system 12, more
`than one air chiller 14, more than one Water chilling system
`13, or more than one tank 18.
`Another speci?c embodiment of the invention is directed
`to a combined cycle system. There, the exhaust gas from the
`poWer turbine 36 can be passed through a heat recovery
`steam generator (HRSG) 38 to produce steam, shoWn sche
`matically by arroW 44, and “stack gas,” shoWn schematically
`by arroW 45. Further, in another embodiment of a combined
`cycle system, a heat recovery coil 42 may receive the
`exhaust gas 45 from the poWer turbine 36 and produce hot
`Water or steam, shoWn schematically by arroW 48. The hot
`Water or steam 48 produced either by the HRSG 38 or the
`heat recovery coil 42 may advantageously be used to supply
`poWer to an absorption chiller 26, the importance of Which
`Will be discussed beloW.
`As mentioned, it is advantageous to loWer the temperature
`of the inlet air 15a to a temperature T2 that is as loW as
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`PAGE 7 of 13
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`PETITIONER'S EXHIBIT 1306
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`

`
`US 6,470,686 B2
`
`7
`possible. The change in air temperature from T1, before
`entering the air chiller 14, to T2, after exiting the air chiller
`14, is referred to herein as AT. Even small increases in AT,
`i.e., lowering T2 can effect signi?cant increases in the
`capacity of the gas turbine system. For example, in a
`particular gas turbine, an increase in AT of about 26° F.
`(about 1° C. to about 2° C.) may increase the turbine output
`by about one percent.
`An important aspect of the apparatus of this invention is
`a chilling Water system or loop, Which includes circulating
`chilling Water 16 that circulates through the specially
`circuited, high AT air chiller 14 and back through chillers
`piped in series to a thermal Water storage tank 18 for storing
`the chilling Water 16. The term “loop” preferably refers to
`conventional pipage, e.g. pvc or steel pipes having valves
`(not shoWn) Where appropriate. The features of this chilling
`Water loop Will noW be described With reference to FIG. 1,
`Where, for ease of comprehension, the Water Within the loop
`is referred to generally With numeral 16, and the various
`streams of Water Within the loop are referred to With the
`numeral 16 folloWed by an alphabetic character to distin
`guish betWeen various streams of Water Where necessary.
`The chilling Water loop includes a Water chilling system
`13. The Water chilling system 13 may include any number of
`conventional Water chillers installed either in parallel or in
`series but preferably With at least tWo chillers piped in series
`so as to stage the temperature drop of the Water into an
`intermediate and a loWer temperature chiller. This saves
`poWer on the upstream chiller and makes the system more
`ef?cient. If the poWer plant is a combined cycle plant and if
`there is suf?cient exhaust energy available from either the
`steam turbine exhaust (stream 46) or heat recovery coil
`(stream 48), then it is preferable as shoWn in FIG. 1 for the
`Water chilling system 13 include an absorption chiller 26
`Which may derive its poWer from the HRSG 38, or the heat
`recovery coil 42, or both, and a mechanical chiller 24. The
`absorption chiller 26 and the mechanical chiller 24 are
`shoWn in series, as that is the preferred arrangement With the
`absorption chiller placed upstream of the mechanical chiller,
`hoWever they may be placed in parallel depending upon
`system needs. An object of the Water chillers is to chill the
`chilling Water 16 to a suf?ciently loW temperature so that the
`chilling Water 16 can then be used to chill the inlet air 15a
`in the air chiller 14 With a minimum Water ?oW rate and
`maximum Water AT. Preferably, the temperature of the
`chilling Water 16c is about 34° F. (about 1° C. to about 2° C.)
`to about 40° F. (about 4° C. to about 5° C.) prior to entering
`the air chiller 14. A number of conventional devices can be
`used to chill the Water going to the Water storage tank 18. For
`example, the chilling Water can be chilled before it is ever
`introduced to the tank, by passing the chilling Water 16d
`from the air chiller either through a mechanical chiller 24 or
`an absorption chiller 26 (driven by hot Water or steam 44, 48
`from the HRSG or LP steam 46 coming out of the steam
`turbine 40) to provide chilling Water 16a that is then
`introduced to the tank 18. Ahybrid chilling arrangement can
`also be used Whereby both mechanical 24 and absorption 26
`chillers are used in combination. The preferred arrangement
`is to circulate the Warm Water 166 from the tank 18 or the
`heated Water 16d from the air chiller 14 to the upstream
`absorption (or mechanical) chiller 26 ?rst Where the Water
`16d Will be chilled from range of about 54° F. (about 12° C.)
`to about 65° F. (about 19° C.) to a range of about 40° F. (or
`about 4° C. to about 5° C.) to about 48° F. (or about 8° C.
`to about 9° C.). The Water 16d then circulates through the
`doWnstream mechanical chiller 24 Where it may be chilled
`further to about 34° F. (or about 1° C. to about 2° C.) to about
`40° F. (or about 4° C. to about 5° C.).
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`55
`
`60
`
`65
`
`8
`The thermal Water storage tank 18 is preferably a ther
`mally insulated vessel, having an upper opening or connec
`tion or top inlet/outlet 20. In other speci?c embodiments,
`e.g., Where an open tank is used, the top “opening” or top
`inlet can be the open top of the tank, so that Water can be
`piped into the tank through the top. The tank 18 may be
`made from any material having the strength and insulation
`qualities necessary for a thermal Water storage tank,
`hoWever, preferably, the tank 18 is constructed of steel or
`concrete. The top inlet/outlet 20 (also referred to herein as an
`“opening”) both receives heated Water 16d from the air
`chiller 14 during a discharge cycle, and expels heated Water
`166 during a charge cycle. (The charge and discharge cycles
`Will be explained in further detail beloW) The thermal Water
`storage tank 18 preferably also has a loWer connection or
`bottom inlet/outlet 22 (or “opening”). The bottom inlet/
`outlet 22 both receives chilled Water 16a from Water chilling
`system 13 during the charge cycle, and discharges chilled
`Water 16b to the air chiller 14 during the discharge cycle.
`Furthermore, the system shoWn in FIG. 1 also alloWs a
`“partial storage” strategy Whereby the chilled Water in the
`tank can be used to supplement the Water produced by the
`chillers such that both can be provided to the air chiller 14
`to alloW longer periods of on-peak chilled air going to the
`gas turbine.
`In accordance With the invention, the Water 16 in the tank
`18 is “strati?ed” according to temperature. That is, the loWer
`temperature Water (about 33° F. (about 0° C. to about 1° C.)
`to about 40° F. (about 4° C. to about 5°
`resides at the
`bottom of the tank. Broadly, the temperature at the bottom
`of the tank may be in the range of from about 33° F. (about
`0° C. to about 1° C.) to about 40° F. (about 4° C. to about
`5° C.). Preferably, the temperature of the Water in the bottom
`of the tank is in the range of from about 33° F. (about 0° C.
`to about 1° C.) to about 36° F. (about 2° C. to about 3° C.).
`Most preferably the temperature of the Water in the bottom
`of the tank is in the range of from about 33° F. (about 0° C.
`to about 1° C.) to about 34° F. (about 1° C. to about 2° C.).
`The higher temperature Water (typically about 60° F. (about
`16° C.) to about 70° F. (about 21° C.), typically having a
`loWer density, remains at the upper portions of the tank.)
`Preferably, the entire tank 18 Will be occupied by loWer
`temperature Water (about 33° F. (about 0° C. to about 1° C.)
`to about 34° F. (about 1° C. to about 2°
`after a charge
`cycle (discussed beloW) is completed. The tank should be
`capable of storing suf?cient chilled Water 16 to provide air
`cooling during an entire discharge cycle (discussed beloW).
`Further, the