An Introduction to Turbine Inlet Cooling . . . . . . . . . . . 4

A Perspective on the U.S. Electric Power Industry . . . . . . . . . . 6

Evaporative Cooling Technologies for Turbine Inlet Cooling . . . . . . . .10

Chiller Technologies for Turbine Inlet Cooling . . . . . . . . . . 12

Thermal Energy Storage Technologies for Turbine Inlet Cooling . . . . . . . . . . . . . . . . 16

Hybrid Systems & LNG forTurbine Inlet Cooling (TIC) . . . . . . 18

Turbine Inlet Cooling (TIC) Installation Success Stories . . . . . . 20

Turbine Inlet Buyers Guide . . . . . . .26

Don’t add generators, boost output!

Instead of adding gas-turbine generators tomeet electricity demand—which is forecast to jump 43% by 2020—you can enhance theoutput of existing generators with mechanicalchillers from YORK.

Based on proven water-chiller and heatexchanger technology, mechanical chillersprovide the cooling capacity, dependability, and constant conditions for optimumoutput from the gas turbine. And thanks to relatively constantconditions provided bymechanical cooling, turbine lifeand maintainability may besignificantly improved, too.

Optimize with the best chiller option:YORK

When you’re selecting a liquid chiller for aturbine inlet-air-chilling (TIAC) system, considerYORK: the industrial cooling experts. YORK®

chillers and compressors are used in some ofthe most demanding, 24/7 petrochemical andgas-compression applications on Earth. Thatsame industrial-grade dependability is built into

the YORK chillers that serve as theheart of TIAC systems.

Get the experience and options to optimize your installation. CallBill McAuliffe at 832-204-9435.

Meet growing power demand by optimizing power output with YORK® chillers

Boost Turbine Output with Inlet-Air ChillingBoost Turbine Output with Inlet-Air Chilling

COOL YOUR JETS

4

Appeared in December 2003 Energy-Tech Magazine

What is TIC?TIC is cooling of the air before it

enters the compressor that supplies high-pressure air to the combustion chamberfrom which hot air at high pressure entersthe combustion turbine. TIC is also calledby many other names, including combus-tion turbine inlet air cooling (CTIAC), tur-bine inlet air cooling (TIAC), combustionturbine air cooling (CTAC), and gas turbineinlet air cooling (GTIAC).

Why Cool Turbine Inlet Air? The primary reason TIC is used is to

enhance the power output of combustionturbines (CTs) when ambient air tempera-ture is above 59°F. The rated capacities ofall CTs are based on the standard ambientconditions of 59°F, 14.7 psia at sea levelselected by the International StandardsOrganization (ISO). One of the commonand unattractive characteristics of all CTsis that their power output decreases as theinlet air temperature increases as shownin Figure 1. It shows the effects of inletair temperature on power output for twotypes of CTs: Aeroderivative andIndustrial/Frame. The data in Figure 1 aretypical for the two turbine types for dis-

cussion purposes. The actual characteris-tics of each CT could be different anddepend on its actual design. The data inFigure 1 shows that for a typicalaeroderivative CT, as inlet air temperatureincreases from 59°F to 100°F on a hotsummer day (in Las Vegas, for example),its power output decreases to about 73percent of its rated capacity. This couldlead to power producers losing opportuni-ty to sell more power just when theincrease in ambient temperature increasespower demand for operating air condi-tioners. By cooling the inlet air from100°F to 59°F, we could prevent the lossof 27 percent of the rated generationcapacity. In fact, if we cool the inlet air toabout 42°F, we could enhance the powergeneration capacity of the CT to 110 per-cent of the rated capacity. Therefore, ifwe cool the inlet air from 100°F to 42°F,we could increase power output of anaeroderivative CT from 73 percent to 110percent of the rated capacity or boost theoutput capacity by about 50 percent ofthe capacity at 100°F. The primary reasonmany power plants using CT cool theinlet air is to prevent loss of power outputor even increase power output above therated capacity when the ambient tempera-ture is above 59°F.

What are the Benefits of TIC?The primary benefit of TIC is that it

allows the plant owners to prevent loss ofCT output, compared to the rated capacity,when ambient temperature rises above59°F or the plant is located in a warm/hotclimate region. As discussed in the earliersection, TIC can even allow plant ownersto increase the CT output above the ratedcapacity by cooling the inlet air to below59°F.

The secondary benefit of TIC is thatit also prevents decrease in fuel efficiencyof the CT due to increase in ambient tem-perature above 59°F. Figure 2 shows theeffect of inlet air temperature on heat rate(fuel require per unit of electric energy)for the two types of CTs discussed in theearlier section. It shows that for anaeroderivative, CT increase in inlet airtemperature from 59°F to 100°F increasesheat rate (and thus, decreases fuel effi-ciency) by 4 percent (from 100 percent at59°F to 104 percent at 100°F) and thatcooling the inlet air from 59°F to 42°Freduces the heat rate (increases fuel effi-ciency) by about 2 percent (from 100 per-cent to about 98 percent).

The other benefits of TIC includeincreased steam production in cogeneration

An Introduction to Turbine Inlet CoolingDharam V. Punwani

120

110

90

80

7040 50 60 70 80 90 100

100

Pow

erO

utpu

t,%

ofRa

ted

Capa

city

Inlet Air Temperature, °F

Industrial

Aeroderivative

104

9640 50 60 70 80 90 100

100

Hea

tRat

e,%

ofD

esig

nH

eatR

ate

Inlet Air Temperature, °F

Industrial

Aeroderivative

Figure 1: Effect of Inlet Air Temperature on Combustion Turbine Power Output Figure 2: Effect of Ambient Temperature on Combustion Turbine Heat Rate

COOL YOUR JETS

5

Appeared in December 2003 Energy-Tech Magazine

plants, and increased power output ofsteam turbines in combined cycle systems.

In summary, there are many benefits ofTIC when the ambient temperature isabove 59°F:

7 Increased output of CT7 Reduced capital cost for the

enhanced power capacity7 Increased fuel efficiency7 Increased steam production in

cogeneration plants7 Increased power output of steam tur-

bine in combined cycle plants

How Does TIC Help Increase CT Output?

Power output of a CT is directly pro-portional to and limited by the mass flowrate of compressed air available to it fromthe air compressor that provides high-pressure air to the combustion chamber ofthe CT system. An air compressor has afixed capacity for handling a volumetricflow rate of air. Even though the volumet-ric capacity of a compressor is fixed, themass flow rate of air it delivers to the CTchanges with changes in ambient air tem-perature. This mass flow rate of airdecreases with increase in ambient tem-perature because the air density decreaseswhen air temperature increases.Therefore, the power output of a combus-tion turbine decreases below its ratedcapacity at the ISO conditions (59°F, 14.7psia at sea level) with increases in ambi-ent temperature above 59°F. TIC allowsincrease in air density by lowering thetemperature and thus, helps increase massflow rate of air to the CT and results inincreased output of the CT.

What are the AvailableTechnology Options for TIC?

Many technologies are commerciallyavailable for TIC. These technologies canbe divided into the following major cate-gories/groups:

7 Evaporative: wetted media, fogging,and wet compression/ overspray

7 Refrigeration: mechanical andabsorption chillers without or withthermal energy storage (TES)

7 Special Application Technologiesi.e., re-vaporization of liquefied nat-ural gas (LNG)

7 Hybrid Systems: a mix of mechani-cal and absorption chillers

All technologies listed above haveadvantages and disadvantages. Many pub-lished articles are available on these tech-nologies. A number of these publicationsare listed in the Library section of theTurbine Inlet Cooling Association website(www.turbineinletcooling.org).

What are the Economics of TIC?

Even though it is difficult to generalizethe overall economics of TIC because theydepend on many factors, it generallyrequires less investment ($/kW) thaninstalling additional uncooled CT toachieve similar increase in plant capacity.It is not unusual for TIC to increase CToutput capacity at less than half the capitalcost of installing an additional uncooledCT.

The various factors that affect theoverall economics of TIC include the fol-lowing:

7 Cooling Technology7 Weather data for the geographic

location of the CT plant7 CT plant capacity and operational

mode (Peaking, Cogeneration, orCombined Cycle)

7 Market value of electric energy andpower demand profile

7 Price of fuel (Natural gas or fuel oil)7 Market value of cogenerated steam

and steam demand profile7 Cost of capital

Who is using TIC?Many CT plants across the U.S. and

around the world are using various TICtechnologies that improve their perform-ance and economics. A database of someof these installations is available in theExperience Database section of the TurbineInlet Cooling Association website.

What are the Plans for this Column?

This column will cover the followingsequence of TIC topics in the subsequentissues of the Energy-Tech:

7 Evaporative cooling technologies:wetted media, fogging, and over-spraying/wet compression

7 Refrigeration/Chiller technologies:mechanical and absorption

7 Thermal energy storage technolo-gies: ice, chilled water, and stratifiedfluid

7 Special application technologies andhybrid systems

7 Performance test protocol7 Commissioning, Maintenance &

Operation

What is the Mission of TICA?The mission of the Turbine Inlet

Cooling Association (TICA), a not-for-profit organization, is to promote the devel-opment and exchange of knowledge relatedto TIC and to become the premier one-stopsource of information on TIC. For moreinformation about TICA, visit its website atwww.turbineinletcooling.org.

Dharam V. Punwani is president of Avalon Consulting, Inc. locatedin the Chicagoland area (Naperville), and has over 36 years ofexperience in energy technologies. Avalon provides technical andeconomic analyses related to TIC and cogeneration systems. He waschairman of TICA in 2002 and now serves as its Executive Director.

We all know that the U.S. electric power industry is one of the best in theworld. However, it’s far from perfect in that there are several structuralproblems which must be addressed and fixed as soon as possible. From the

perspective of the electric power consumers and the environment, I believe the U.S. power industry problems include thefollowing:

7 Increasing grid instability

7 High electricity cost during peak periods

7 High environmental emissions during hot weather

The lack of grid reliability generally occurs during hot weather when we need electric power themost. Some of the reliability problems stem from the aging grid infrastructure and some from the lack ofsufficient supply to meet demand from the grid-connected loads.

As we all know, the electric energy and demand charges are high during peak periods. Sometimesthese charges are as much as five times as those during off-peak periods, and it is not because the powerproducers are gouging the consumers. The on-peak prices are influenced by two major factors: demandand supply, and the types of power plants brought on stream to meet peak loads. Many of these peakingplants have low energy efficiencies that increase the cost of producing electric power. In addition, whenthe weather becomes hot, the energy efficiency decreases and the cost of producing electric powerincreases for all power plants that use combustion turbines.

Environmental emissions increase during hot weather for two reasons: decreased energy efficiencyof all combustion turbines, and startup of older, dirtier, and inefficient peaking plants. Operating thesepower plants at low efficiencies not only increases environmental emissions, they also consume morefuel (natural gas, fuel oil, or diesel) per unit of electric energy produced. Over the last 20 years, most ofthe new power plants brought on stream in the U.S. use natural gas (Figure 1), and electric generationrepresents the highest demand sector for growth for natural gas (Figure 2). Natural gas demand for power

6

Greater summer power demand and more advanced gas turbines lead toan increased need for turbine inlet chilling. Photo courtesy of TAS, Ltd.

A Perspective on the U.S.Electric Power Industry

PROBLEMS, SOLUTIONS & NEEDSBy Craig M. Hurlbert

generation increases during summer(Figure 3). We all have seen the prices ofnatural gas peak much higher than everbefore, while the average price of naturalgas also seems to settle at a higher levelthan before (Figure 4). U.S. production ofnatural gas is not sufficient to meetdemand; we now must import LNG to sup-plement it. Whether the combustion tur-bines use natural gas or oil, it is imperativethat we not continue to operate our powersystems at low efficiencies, particularlywhen much of the fuel source originates inan unstable and hostile region of the world.

SolutionsWe need a multi-faceted approach for

solving the problems within the powerindustry. This approach should include thefollowing components:

7 Modernizing grid infrastructure7 Demand side management7 Distributed generation 7 Power augmentation

We cannot afford to continue with theantiquated grid infrastructure - it must bemodernized. Without it, all other approach-es for improving grid reliability will neverbe adequate. Modernizing grid infrastruc-ture is going to require a hefty budget fromindustry and government. It is not a near-term solution; it will require significanttime. Nonetheless, improving the gridinfrastructure alone will not improve gridreliability.

We should bring demand side manage-ment back to the forefront. We shouldexplore with more vigor the ways to shiftpower usage from day to night. It is time

for the concept of thermal energy storage(TES) to garner some serious considerationfrom the electricity demand side. TESallows electricity users to shift powerdemand from day to night; yet inexplicablyit is not a serious part of the demand sidemanagement dialog today. Of course, weshould continue to develop more energy-efficient light bulbs and refrigeration sys-tems, etc. However, demand side manage-ment alone does not completely bridge thegap between power supply and demand.

Distributed generation can reduce loadon the grid and therefore help improve gridreliability. The U.S. Combined Heat andPower Association (USCHPA) is makingcommendable efforts for disseminatinginformation about the benefits of distrib-uted generation including combined heatand power. The USCHPA is a private, non-profit association, formed in 1999 to pro-mote the merits of CHP and to achievepublic policy support. It is attempting tocreate a regulatory, institutional, and mar-ket environment that fosters the use ofclean, efficient CHP as a major source ofelectric power and thermal energy in theU.S. The goal of the USCHPA is toincrease CHP generation capacity in theU.S. from 46 GW in 1998, to 92 GW by2010. The traditional capital cost requiredfor CHP systems is usually higher than thatfor centralized generation. New packagedCHP systems are under development withindustry and government funding; thesesystems are energy efficient, will helpimprove grid reliability, and will conservefuel resources.

Of these four solutions, PowerAugmentation could have the biggest

potential impact in the immediate term.Power augmentation is an approach thatallows combustion turbine (CT) powerplants to continue to produce their ratedpower capacities—or more than the ratedcapacities— especially during hot weatherconditions. Turbine Inlet Cooling (TIC) hasbeen successfully used at many powerplants across the world for power augmen-tation. While the TIC technologies in usetoday are at least 20 years old, powerindustry executives and planners remainalarmingly uneducated on this provenoption. TIC increases energy efficiencies ofCT power plants, is a well-proven technol-ogy, and serves as a lower-cost option com-pared to adding peaking plants. In addition,it can be easily retrofitted to existing powerplants or incorporated into the design ofnew plants.

Overall, TIC helps maximize the valueof existing and new power generationassets, and is responsive to all three powerindustry problems: grid reliability, cost ofproducing electricity, and environmentalemissions. Some believe that as a directresult of the proliferation of CT basedpower generation, TIC is the most impor-tant breakthrough in the last 25 years in thepower generation industry. According to aresearch study by independent consultantFrost and Sullivan, TIC should be at least a$1 billion per year opportunity based on itsvalue proposition. The Turbine InletCooling Association (TICA) promotes thedevelopment and exchange of knowledgerelated to TIC for enhancing power genera-tion worldwide.

Don’t you think we should give atleast equal weight to maximizing the

7

450

400

350

300

250

200

150

100

50

0

Billi

onKi

low

attH

ours

Oil Gas

Year1975 1980 1985 1990 1995 2000

New Electric Demand: Most New Generation Capacity Utilizes Natural Gas (Primarily for Environmental Reason)

Source: National Petroleum Council, Sept. '03

10

8

6

4

2

0

12

1990 1995 2000 2005 2010 2015 2020 2025

CNG vehicles

Projections

New Electric Demand: Electric Generation Represents the Highest Sector Demand Growth for Natural Gas

History

Source: Energy Information Administration, Annual Energy Outlook 2003

Commercial

Residential

Industrial

ElectricGenerators

Commercial

Residential

Industrial

ElectricGenerators

Figure 1 Figure 2

potential of our existing power plants aswe do to building new ones? Isn’t it sensi-ble to make what we have more energyefficient? It does make sense, especiallywhen TIC technology costs, in most cases,a fraction of a new plant, is more environ-mentally friendly, and has virtually no neg-ative impact (and some positive) on theexisting transmission system.

NeedsEven though TIC provides a simple,

proven solution, it is not yet on the radarscreen. The country needs leaders withauthority in industry and government torise and start looking into the electricpower problems and the potential benefitsoffered by TIC.

Remember when Congress passed thePublic Utility Regulatory Policy Act(PURPA) in the late 1970s? It did so with astrong belief—and rightfully so in hind-sight—that consumers would benefit great-ly from competition. A savvy power indus-try historian could argue that PURPA actu-ally led to the merchant plant debacle andtherefore was a failure. The counter to thatis yes, PURPA blazed that now infamoustrail, but utilities today are much morecompetitive-minded than they were in themid-1960s and 1970s, and as such con-sumers are better off. But the real questionis, if PURPA, and the threat of a competi-tive deregulated market, had not been cre-ated, would utilities have changed theirmindset by themselves? The answer to thisquestion is a resounding, “No!”

History illustrates that the governmenthas a role in helping the energy industrymake necessary structural changes to lookout for the good of the consumer and the

environment. Now that we may be slippingback toward the utility command-and-con-trol mindset of old, away from the IPPmodel, the time has come for anotherstructural shift. It is time for the nextPURPA legislation. It is time for Congressto step up and take a lead on behalf of theratepayers in the electric power industry.

If we are to maintain our competitiveadvantage as a country, then we must keepour energy costs as low as possible. Wemust protect the environment to the great-est extent possible, and quickly escalate theissue to higher levels within the industryand government where real change can becreated. Why is power augmentation not atopic of big discussion inside the seeming-ly ever-stalled Energy Bill? Our legislators,aside from thinking about long-term solu-tions, should also look into sound ideaswith immediate impact in securing ourfuture. Power augmentation via TIC is alow hanging fruit with a positive economicand environmental impact—somethingboth sides of the House should be able toagree upon. History shows that this type ofchange only happens when Congress stepsin and makes change mandatory. It is timefor power augmentation to make its way tothe forefront.

As an industry, we need to stronglyencourage Congress to break free from thelobbying quagmire that has become theEnergy Bill, and get serious about positivestructural changes in the electricity indus-try. Meanwhile, individual power plantdevelopers, owners, and operators shouldalready be aggressively exploring andimplementing economic retrofits of poweraugmentation, including TIC.

While the technical problems facingour industry are serious, there are realistic

solutions for these problems that benefitboth the ratepayers and the environment.However, our industry today is sufferingfrom something much more serious, some-thing with no technical solution. We are inthe midst of a serious industry wide “lead-ership vacuum.” This vacuum has placed usin a state of collective inaction on any mat-ter of importance. I feel uncomfortablesaying this, but I do not think our industrycan do this alone – I think we must haveinterference from Congress, and the EnergyBill would be a great vehicle for this“intervention.”

It is time for leaders to emerge in theU.S. power industry!

Figures 1-4 were derived from the fol-lowing paper presentation: “Natural GasMarkets Update for the Ethanol Industry:Identifying Market Fundamentals andManaging Price Risk.”

8

140

120

100

80

60

40

20

0

Billi

onCu

bic

Feet

PerD

ay

MonthSource: Energy and Environmental Analysis, Inc.

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

New Electric Demand: 1997 Daily Gas Loads Show Dominant Winter Demand Driven by Weather

PowerIndustrialCommercialResidential

Year

Source: Energy Information Administration, Annual Energy Outlook 2003

Natural Gas Prices at the Wellhead Have Been High and Volatile

2002200019981996199419921990198819861984198219800

2

4

6

8

Nom

inal

Dolla

rsPe

rTho

usan

dCu

bic

Feet

Figure 3 Figure 4

Craig M. Hurlbert is President of TAS,Houston, a leading provider of inletcooling solutions for the global energyindustry. Previous employmentincludes key leadership positions withNorth American Energy Services(NAES), Stewart & Stevenson (S&S),and GE Energy Services. He wasPresident and CEO of the PIC EnergyGroup, and immediately prior to join-ing TAS was General Manager ofPratt & Whitney’s sales and marketingbusiness – P2 Energy. Craig is thecurrent President of the Turbine InletCooling Association (TICA), www.tur-bineinletcooling.com.

COOL YOUR JETS

The inaugural issue of this column waspublished in the December 2003 issue of theEnergy-Tech. It provided an introduction tothe turbine inlet cooling (TIC) and addresseda number of frequently asked questions:What is it? Why use it? What are its bene-fits? How does it work? What are the tech-nology options? What are its economics?Who is using it? It also discussed plans forthe future issues of this column and Energy-Tech’s plans for a cover story and a specialsupplement for TIC in cooperation with theTurbine Inlet Cooling Association (TICA).

As per the plans for this column, thecurrent column discusses three evaporativetechnologies commercially used for TIC andtheir economics: wetted media, fogging, andwet compression/over spraying. These tech-nologies differ from one another in themethod and/or the quantity of water added tothe inlet air entering the compressor of a CTsystem. All technologies have their pros andcons. As discussed in the inaugural issue ofthis column, the selection of an optimumtechnology for a specific power plantdepends on a number of factors, includingplant’s geographical location, CT character-istics, plant operating mode, market value ofelectric energy, and fuel cost. Many pub-lished articles are available on these tech-nologies. A number of these publications arelisted in the Library section of the Website(www.turbineinletcooling.org) of the TurbineInlet Cooling Association.

TechnologiesThe primary advantages of evaporative

cooling technologies are their low capitaland operating costs. The primary disadvan-tage of these technologies is that the extentof cooling achieved is limited to the wet-bulb temperature (WB) and, therefore, theiroutputs vary depending upon the weather.These technologies are more efficient in hotand dry weather and less efficient in hot andhumid weather conditions. These technolo-gies also consume lots of water and mayrequire water treatment/conditioning depend-ing upon manufacturers’ specifications andthe quality of available water.

Wetted media is the first technologyused for TIC. In this technology, water isadded to the inlet air by exposing it to a filmof water in one of the many types of wettedmedia. Honey-comb-like medium is one ofthe most commonly employed media. Thewater used for wetting the medium mayrequire treatment, depending upon the quali-ty of water and the medium manufacturer’sspecifications. Wetted media can cool theinlet to within 85% to 95% of the differencebetween the ambient dry-bulb and wet-bulbtemperature. On an overall basis, this is themost widely used technology.

In Fogging, water is added to the inletair by spraying very fine droplets of water.Fogging systems can be designed to producedroplets of variable sizes, depending on thedesired evaporation time and ambient condi-

tions. The water droplet size is generally lessthan 40 microns and on an average it isabout 20 microns. The water used for fog-ging typically requires demineralization.Fogging systems can cool the inlet air towithin 95% to 98% of the differencebetween ambient dry-bulb and wet-bulb tem-perature and is therefore, slightly more effec-tive than the wetted media. Its capital cost isvery comparable to that for the wetted mediaand it is the second most applied technologyfor TIC.

In Wet Compression/Over Sprayingwater is added to the inlet air as a fog just asit is done for fogging. However, the amountof fog added is a lot more than can be evapo-rated under the conditions of the ambient air.The inlet air stream carries the excess foginto the compressor section of the CT whereit further evaporates, cools the compressedair and creates extra mass for boosting theCT output beyond that possible with theevaporative cooling technologies. Theamount of excess fog carried into the com-pressor depends on where the fog is added inthe inlet section of the CT system.

EconomicsFor the purpose of discussing the eco-

nomics of wetted media and fogging, wewill use examples of the following two typesof cogeneration plants located in LosAngeles, CA:

1. 83.5 MW Industrial/Frame CT2. 42.0 MW Aeroderivative CT

10

Evaporative Cooling Technologies for Turbine Inlet Cooling

Dharam V. Punwani

71.0No Cooling Wetted Media

Cooling Technology

Fogging

75.3

81.3

73.0

75.0

77.0

79.0

81.0

83.0

85.0

Pow

erO

utpu

t,M

W

81.9

30.0No Cooling Wetted Media

Cooling Technology

Fogging

34.1

39.9

32.0

34.0

36.0

38.0

40.0

42.0

44.0

Pow

erO

utpu

t,M

W

40.4

Figure 1. Effect of Cooling Technology onNet Power Output of the Industrial CT

Figure 2. Effect of Cooling Technology onNet Power Output of the Aeroderivative CT

Figure 3. Effect of Cooling Technology onTotal Plant Capital Cost ($) for theIndustrial CT

730,000No Cooling Wetted Media

Cooling Technology

Fogging

740,000750,000760,000770,000780,000790,000800,000810,000820,000830,000840,000

Plan

tCap

italC

ostw

ithTI

C

766,794772,316

832,141

COOL YOUR JETS

When the ambient temperature in LosAngeles is 87°F dry-bulb and coincidentwet-bulb temperature is 64°F the output ofthe uncooled 83.5 MW and 42 MW (capaci-ties at ISO conditions of 59°F and 14.7 psia)cogeneration plants drops to about 75.3 MWand 34.1 MW, respectively as discussed inFigures 2 and 3. Compared to the ratedcapacities of the two plants, the reduced out-puts represent loss of capacity by about 10%and 19%, respectively.

Assuming 90% and 98% approaches tothe difference between the dry-bulb and wet-bulb temperatures for the wetted media(evaporative cooling) and fogging technolo-gies, these two technologies can cool theinlet air to 66.3°F and 64.5°F respectively.Comparisons of the two evaporative coolingtechnologies with the uncooled CT in termsof total power plant output and incrementalpower are shown in Figures 1 and 2.

The results in Figure 1 show that wettedmedia and fogging can enhance the capaci-ties of the larger uncooled system from 75.3MW to 81.3 MW and 81.9 MW, respective-ly. Therefore, these TIC technologies canrestore most of the 10% lost capacity towithin 3% of the rated capacity.

The results for the aeroderivative CT,shown in Figure 2, are similar but more pro-nounced than those for the industrial/frameCT. The capacity of this uncooled systemgoes up from 34.1 MW to 39.9 MW and40.4 MW by the evaporative cooling andfogging technologies, respectively and thus,restores most of the 19% lost capacity towithin 4% of the rated capacity.

The impacts of the two TIC technolo-gies on the installed cost for the total plantcapacity for the two types of CTs areshown in Figures 3 and 4. The costs inthese figures are based on the followinginstalled costs:

Un-cooled CT plant:$750,000/MW at ISO conditions

Wetted Media:$1900/MW CT capacity at ISO

Fogging:$1900/MW CT capacity at ISOThe results in the above Figures show

that the total plant capital cost, expressedas $/MW, is lower for the plantswith TIC than those for theuncooled systems.

The capital costs for the incre-mental power output capacities madeavailable by TIC are shown in figures5 and 6. These figures show the capi-tal costs for the additional power out-put capacity available from the exist-ing CT by TIC are significantly lowerthan the option of installing an addi-tional uncooled CT. This is one ofthe most important benefit of TIC.

As stated earlier, all of the abovediscussions relate to a situation whenthe ambient dry-bulb and wet-bulbtemperatures are 87°F and 64°F,respectively. However, this informa-tion is not sufficient to decidewhether TIC is economically attrac-tive and if so which cooling technolo-gy will be economically most attrac-tive. Such estimates require calcula-tions using hourly weather data for8,760 hours of the year and alsorequire information for cost of fuel,power demand profile and marketvalue of power produced (which mayvary with the time of day).

In addition, as stated earlier, theresults of the various TIC technolo-gies for these plants located inHouston, TX and Las Vegas, NVwould be different from those dis-cussed for Los Angeles, CA.

USERSMany CT plants across the U.S

are using various evaporative coolingtechnologies that best suit their needs.A database of some of these installa-tions is available in the ExperienceDatabase section of the Website

(www.turbineineltcooling.org) of the TurbineInlet Cooling Association.

11

740,000No Cooling Wetted Media

Cooling Technology

Fogging

790,000

840,000

890,000

940,000

Plan

tCap

italC

ostw

ithTI

C,$/

MW

780,954792,029

924,784

0No Cooling Wetted Media

Cooling Technology

Fogging

100,000

200,000

300,000

400,000

500,000

600,000

700,000

800,000

900,000

Plan

tCap

italC

ostw

ithTI

C,$/

MW

23,96526,310

832,141

0No Cooling Wetted Media

Cooling Technology

Fogging

200,000

400,000

600,000

800,000

1,000,000

Incr

emen

talP

lant

Capi

talC

ost,

$/M

W

13,10913,779

924,784

Figure 4 Effect of Cooling Technology on TotalPlant Capital Cost for the Aeroderivative CT

Figure 5. Effect of Cooling Technology on Incre-mental Plant Capital Cost for the Industrial CT

Figure 6. Effect of Cooling Technology onIncremental Plant Capital Cost for theAeroderivative CT

Dharam V. Punwani is president of Avalon Consulting, Inc.located in the Chicagoland area (Naperville), and has over36 years of experience in energy technologies. Avalon pro-vides technical and economic analyses related to TIC andcogeneration systems. He was chairman of TICA in 2002and now serves as its Executive Director.

TechnologiesA TIC system that uses a chiller draws

the turbine inlet air across a cooling coil inwhich either chilled water or a refrigerantis circulated as shown in Figure 1. Airsidepressure drop across the cooling coil couldbe 1 to 2 inches of water column. Thechilled water could be supplied directlyfrom a chiller or from a thermal energystorage (TES) tank that stores ice or chilledwater. Chiller capacities are rated in termsof refrigeration ton (RT). One RT capacitychiller is capable of removing heat at therate of 12,000 Btu/hr. The two most com-mon type of chiller technologies used forTIC are mechanical chillers and absorptionchillers.

Mechanical Chillers, also known asvapor compression chillers, are the mostcommon chillers used for TIC. Thesechillers are similar to those commonly usedin heating, ventilation, and air conditioning(HVAC) systems for cooling air in largecommercial buildings.

A mechanical chiller can cool the tur-bine inlet air to any temperature down to42°F. Even though the chiller could coolthe inlet to temperatures even lower than42°F, the lower temperatures are generallynot desirable to avoid the potential offorming ice crystals in the bell mouth ofthe compressor. The temperature dropacross the bell mouth is estimated to be

about 10°F and therefore, the turbine inletair is not recommended to be cooled below42°F. A mechanical chiller could be drivenby an electric motor, natural gas engine, orsteam turbine.

When a mechanical chiller is operatedby an electric motor, it requires electricpower in the range of 0.7 to 0.8 kW/RT,depending on the chiller design. Most ofthis power requirement is for operating thecompressor (0.6 to 0.65 kW/RT).Mechanical chillers do produce net powerenhancement for the power plant by TIC.Electric motor-driven chillers represent theleast capital cost option for TIC systemsusing chillers.

If a natural gas engine operates amechanical chiller, total electric powerrequirement for the chiller system reducesto only about 0.18 kW/RT. Therefore, in aTIC system, a natural gas engine-drivenmechanical chiller allows achievement ofhigher net electric power enhancement thanthat possible with an electric motor drivenchiller. Natural gas engines are generallyused in applications where natural gas isavailable at low cost and/or combustionturbines are operating mechanical equip-ment, i.e., gas compressors and pumps,rather than electric power generators.

If a steam turbine is used for operatinga mechanical chiller, total electric powerrequired by the chiller system is about 0.28

kW/RT. This parasitic power need is higherthan that for the natural gas engine-drivenchiller system because the steam turbinesystem requires more power for the coolingtower pumps. However, its power require-ments are much lower than that for an elec-tric-motor-driven chiller. Therefore, in aTIC system, a steam turbine drivenmechanical chiller allows achievement ofhigher net electric power enhancement thanthat possible with an electric motor drivenchiller. A steam turbine driven chillerrequires about 10 lbs per hour of steam (at120 psig) per RT of cooling. Steam tur-bine-driven systems are economical whensteam is easily and economically availableand it is desirable to maximize the electricpower output of the power plant instead ofusing a part of it for operating chillers.

Absorption Chillers are different fromthe mechanical chillers in that thesechillers do not need a mechanical compres-sor for compressing the refrigerant and thatthe refrigerant they use is either water orammonia, instead of a hydrocarbon fluidused in mechanical chillers. The primarysource of energy for absorption chillers canbe thermal, instead of electrical. Thesource of thermal energy for absorptionchillers could be hot water, steam, or afuel, such as natural gas. These chillersrequire very little electrical energy to oper-ate only a few pumps.

12

Chiller Technologies for Turbine Inlet CoolingDharam V. Punwani

CoolingCoil

Chiller

AmbientAir

CoolingTower

CooledAir

HeatRecoverySteamGenerator

Exhaust toAtmosphere

TurbineExhaust

CondenserWater

CondenserReturn Water

ChilledWater

ReturnWater

Compressor Turbine

Natural Gas

CombustionTurbine

Steam

Figure 1: Schematic Flow Diagram for a CombustionTurbine Plant Using Chillers for TIC

COOL YOUR JETSAppeared in April & June 2004 Energy-Tech Magazine

COOL YOUR JETSAppeared in April & June 2004 Energy-Tech Magazine

Absorption chillers could be single-effect or double-effect chillers. The double-effect chillers are more energy efficient butrequire higher temperature heat and morecapital cost. Absorption chillers couldincorporate a mixture of lithium bromideand water, or ammonia and water.Absorption chillers that use lithium bro-mide-water mixture are significantly morecommonly used than the ammonia watermixture chillers. A single-effect absorptionchiller (lithium bromide and water mixture)can use hot water at least 180°F or 18 lbs/hof steam at 15-psig per RT. A double-effectabsorption chiller (lithium bromide andwater mixture) requires about 10 lbs/h ofsteam at about 115 psig per RT. Theseabsorption chillers are generally used tocool the turbine inlet air to about 50°F.Absorption chillers using ammonia-watermixture can cool the inlet air to 42°F, justas the mechanical chillers.

Advantages & Limitations The power gains realized by evapora-

tive cooling technologies depend on theambient temperature and humidity condi-tions. Evaporative technologies producetheir largest power gains when ambientconditions are dry and hot, and less gainswhen the conditions are very humid. Inaddition, the wet-bulb temperature and theamount of water that can be injected forthe compressor inter-stage cooling limit themaximum power gain achievable by thesetechnologies. These technologies also con-

sume lots of water that may require exten-sive water treatment/conditioning depend-ing upon manufacturers’ specifications andthe quality of available water. The primaryadvantages of these technologies are thelow capital and operating costs.

The primary advantage of using chillertechnologies is that they allow cooling ofthe turbine inlet air to much lower temper-atures and thus, achieve much higherpower capacity enhancements than thosepossible with evaporative cooling technolo-gies. Unlike evaporative cooling technolo-gies, chillers allow cooling of inlet air toany desired temperature, within the limita-tions of the selected chiller, almost inde-pendent of ambient temperature andhumidity conditions. The chiller technolo-gies also do not require any water treat-ment and consume very little or no water.

The primary disadvantage of thechiller technologies is their capital cost.The capital costs of chiller technologiesare higher than those for evaporativecooling technologies. Since the chillersystems also require the inlet air to bedrawn through cooling coils, these sys-tems incur more pressure drop (generallya few inches of water column) on the air-side compared to evaporative coolingtechnologies. However, in spite of thehigh capital cost and additional pressuredrop, these technologies cost much lessthan the combustion turbines without anycooling for providing additional powercapacity in hot weather.

EconomicsThe economics of chiller technologies

for TIC uses an example of a cogenerationpower plant located in Houston, Texas, andhaving a rated capacity of 316.8 MW (3industrial frame CTs of 105.6 MW each).When the ambient temperature in Houstonis 95°F dry-bulb and coincident wet-bulbtemperature is 80°F, the output of thecogeneration plant, without any cooling,drops to about 273 MW. Compared to therated capacity, the plant output drops byabout 44 MW or a capacity loss of about14 percent.

Figure 2 shows the effect of chillertechnology on total plant capacity when theinlet air is cooled from 95°F ambient dry-bulb temperature to 50°F. Total chillercapacity required for cooling the turbineinlet air for the plant is about 18,400 RT.The results in Figure 2 show that the sin-gle-effect lithium bromide-water absorp-tion chiller (hereafter referred to as “theabsorption chiller”) increases the plantcapacity to about 321 MW from its capaci-ty of 273 MW without any cooling.Because of the higher parasitic powerneeds, the electric chiller can raise thecapacity to only about 312 MW.

Figure 3 shows the effect of chillertechnology on net power enhancement forthe same set of conditions as for Figure 2.It shows that the absorption chiller pro-vides the maximum net power capacityincrease of about 48 MW above that at95°F ambient condition. The electric

13

330

320

310

300

290

280

270

260

250

Tota

lPla

ntCa

paci

ty,M

W

NoCooling

273

ElectricChiller

312

AbsorptionChiller

321ISO Rated Capacity = 317 55.0

50.0

45.0

40.0

35.0

30.0

25.0

20.0

15.0NetP

ower

Capa

city

Enha

ncem

ent,

$/M

W

ElectricChiller

AbsorptionChiller

38.5

48.2

Figure 2: Effect of Chiller Technology on Total Plan Capacity Figure 3. Effect of Chiller Technology on Net PowerOutput

chiller provides a capacity enhancement ofabout 39 MW. The results in figures 2 and3 are based on total parasitic loads of 0.81kW/RT and 0.28 kW/RT for the electricand absorption chillers, respectively, andcooling coil pressure drop of 1.5 inches ofwater column.

Figure 4 shows the effect of coolingtechnology on total plant (power plant plusTIC system) cost per MW of the net capac-ity of the plant for similar conditions asthose for Figure 2. The costs in Figure 4are based on the following installed costsfor the power plant and TIC systems:$750,000/MW for the cogeneration plant atthe rated capacity, $834/RT for the com-plete (with cooling coil, chillers, pumps,demisters, and cooling towers) TIC systemwith electric chillers, and $1,240/RT forthe complete TIC system with the absorp-tion chiller. Please note that usually thecosts of installing TIC systems withchillers are not as high as those in thisexample. The reason for the higher costs inthis example is because for retrofitting theplant that had limited area for installingcooling coil, the chilled water had to beproduced at 40°F, instead of the usual44°F. Therefore, the chiller costs includethe effect of chiller de-rating to producewater at 40°F. In addition, the capital costdifferential between the absorption andelectric chiller systems is also not as highas in this example. The absorption chillersystem cost is high here because it alsoincludes the cost of the heat recoveryequipment required for producing hot

water (needed for operating the absorptionchiller) from the exhaust of the heat recov-ery steam generator (HRSG). On thesebases, the total cost of the cogenerationplant without TIC is $237.6 million. Whenthe ambient temperature rises to 95°F andits total capacity decreases to 273 MW, theeffective capital cost of the cogenerationplant rises from $750,000/MW to about$870,000/MW for the same total invest-ment of $237.6 million. The results inFigure 4 show that the total plant cost isthe lowest for the plant with the TIC sys-tem using the absorption chiller.

Figure 5 shows the effect of chillertechnology on the total cost for the incre-mental power capacity enhancement abovethe capacity of the plant at 95°F for thesame set of conditions discussed above forFigure 4. It shows that both TIC systemsprovide incremental power at nearly halfthe cost of an uncooled system and that theTIC system using electric chillers providesthe incremental capacity at the lowest costof $398,000/MW.

The estimates in Figures 2 through 5are only “snapshot” results when the ambi-

ent dry-bulb temperature is 95°F and theturbine inlet air is cooled to 50°F for theplant’s location in Houston. On the basis ofthe information in these figures, it is pre-mature to draw any conclusion about theoptimum technology for this plant. Furtheranalyses are necessary, using hourly weath-er data for all 8,760 hours of the year forestimating the net annual production ofelectrical energy (MWh) and steam, andtheir respective market values and annualoperating and maintenance costs.

SummaryTIC systems using chillers allow com-

bustion turbine systems to produce rated oreven higher than rated power capacity,independent of high ambient temperatures.These systems provide incremental capaci-ty enhancement at almost one-half the perMW capital cost of the uncooled combus-tion turbine systems.

COOL YOUR JETSAppeared in April, & June 2004 Energy-Tech Magazine

14

1,000,000

900,000

800,000

700,000

600,000

500,000

400,000

300,000

200,000

Incr

emen

talC

apita

lCos

tfor

Pow

erCa

paci

tyEn

hanc

emen

t,$/

MW

Electric Chiller Absorption Chiller

398,000

472,328

No Cooling

869,911

Figure 5. Effect of Chiller Technology on Capital Cost for Incremental PlantCapacity Enhancement

Dharam V. Punwani is president of Avalon Consulting, Inc. locatedin the Chicagoland area (Naperville), and has over 36 years of expe-rience in energy technologies. Avalon provides technical and eco-nomic analyses related to TIC and cogeneration systems. He waschairman of TICA in 2002 and now serves as its Executive Director.

880,000

870,000

860,000

850,000

840,000

830,000

820,000

810,000

800,000

Tota

lPla

ntCo

stIn

clud

ing

TIC

Syst

em,$

/MW

AbsorptionChiller

ElectricChiller

810,285 811,616

NoCooling

869,911

Figure 4. Effect of Chiller Technology on Total Plant Investment

16

The TES ConceptA TES-TIC system utilizes all the

component elements of a non-TESchiller-based TIC system. However, TESallows for the time-based decoupling ofall or some of the chiller plant operationfrom the usage of cooling at the turbine’sinlet air cooling coils. This is accom-plished by operating chillers during off-peak times (when the value of power isrelatively low) to freeze ice or to chill astorage tank of water or fluid.Subsequently, during on-peak periods(when the value of power is high) thestorage is utilized (melting the ice orreheating the stored water or fluid) tomeet peak cooling loads at the turbineinlet air cooling coils.

A dual-benefit is achieved by utiliz-ing TES in this manner:

1. Parasitic loads associated withchiller operation are eliminated orlargely reduced during on-peak peri-ods when power is at its highestvalue. (The chillers operate entirelyor primarily during off-peak peri-ods, when the cost or value ofpower is lower.)

2. The chiller plant can be reduced incapacity and capital cost, oftenmore than compensating for thecapital cost of the TES installation.

Advantages & Limitations of TES All TIC technologies have advantages

and limitations. It is always important tounderstand and evaluate technologyoptions for each application.

The use of TES for TIC maintains thebasic attributes and benefits of a non-TESchiller system used for TIC. TES allowscooling of the turbine inlet air to tempera-tures lower than those possible with evapo-rative cooling technologies and thus,achieves much higher power capacityenhancement. The TES-chiller systemallows cooling of inlet air to any desiredtemperature within the limitations of theselected chiller(s). The TES-chiller systemdoes not require elaborate water treatmentand consumes very little water compared toevaporative cooling.

TES systems are most often mated toelectric motor-driven chillers; however,TES systems are also frequently appliedwith steam turbine-driven, engine-driven,and absorption chiller systems, as well aswith hybrid systems using a mix of chillertechnologies.

Supplementing a chiller system withTES helps to address the non-TES chillersystem’s primary drawback, namely a rela-tively high capital cost compared to evapo-rative cooling systems.

The Key Advantages of TES for TIC1. Reduced parasitic power losses,

on-peak2. Reduced capacity and cost of chiller

plant3. Lower capital cost per MW of

power enhancement, on-peak4. Maximized net power enhancement,

on-peak

The Key Limitations of TES for TIC1. Space for the TES tank2. Limited hours per day of maximum

power enhancement

Comparing TES Options for TICVarious TES technology options are

available and already in use in TIC applications. There are two families of TES technologies:

1. Latent heat TES, notably ice (i.e.,“static” ice TES such as “ice-on-coil,” or “encapsulated ice” and“dynamic” ice TES such as “iceharvesters”)

2. Sensible heat TES including chilledwater (CHW) and low temperaturefluid (LTF) storage.

Each technology has unique character-istics and therefore inherent advantagesand limitations.

As each TES technology has charac-teristics that range from excellent to poor, athorough knowledge of those differences(and of the priorities of a particular appli-cation) is critical to achieving an optimummatch for any specific situation. Beyondthe choice of technology, there are manyother variables to be considered in apply-ing TES. These variables include suchitems as: full-shift versus partial-shift sys-tems; daily versus weekly design cycles;operating supply and return temperatures;chiller and chiller driver types; redundantchiller capacity (if any); and siting of theTES equipment.

Thermal Energy Storage Technologies for Turbine Inlet Cooling

John S. Andrepont

Table 1: Generalized Inherent Characteristics of TES Technologies for TIC

Latent Heat (Ice) TES Sensible Heat TESStatic Ice Dynamic Ice Chilled Water LT Fluid

Volume good fair poor fair

Footprint good good fair good

Modularity excellent good poor good

Economy-of-Scale poor fair excellent good

Energy Efficiency fair fair excellent good

Low Temp Capability good good fair excellent

Ease of Retrofit to Chillers fair poor excellent good

Rapid Discharge Capability fair excellent good good

Simplicity and Reliability fair-good fair excellent good

Site Remotely from Chillers poor poor excellent excellent

Dual-Use as Fire Protection poor poor excellent poor

COOL YOUR JETSAppeared in August 2004 Energy-Tech Magazine

COOL YOUR JETS

17

Appeared in August 2004 Energy-Tech Magazine

Specific Users of TES-TICTo date, there has been more than 15

years of experience with TES-TIC installa-tions. Such applications span a wide rangeof application types:

7 TIC applied to new CTs, as well asretrofits to existing CTs;

7 Applications for Simple-Cycle andCombined-Cycle CT plants;

7 CT plant capacities ranging from 1MW to 750 MW;

7 Installations in North America,Europe, and Asia, including a widerange of climates, both hot-arid andhot-humid environments, as well aslocales with year-round hot weatherand those with only brief seasonalhot weather; and

7 Various TES technology types,including Ice TES, Stratified ChilledWater (CHW) TES, and StratifiedLow Temperature Fluid (LTF) TES.

The types of power plants using TES-TIC systems are mostly stand-alonepower generation (utilities and IPPs).However, TES-TIC is also fairly commonat District Energy systems (both at urbanthermal utility systems and at universitycampus energy systems) where centralcooling plants and onsite power genera-tion are employed.

Power plants across the U.S. andaround the globe are employing variousTES-TIC technologies, with the earliestdocumented system in-service in the late

1980s. Detailed data from some of theseinstallations is available within theExperience Database section of the TurbineInlet Cooling Association website,www.turbineinletcooling.org.

Case Study of TES-TIC SystemsDetails for a representative recent

example is provided in the followingElectric Utility Case Study.

Plant & TES-TIC Data7 Middle East (hot-arid climate)7 Existing 750 MW (ISO) Simple-

Cycle plant7 10 x GE 7EA CTs7 Added TIC, from 122°F to 54.5°F

air temp7 Approx. 30,000-ton TIC load, 6

hours per day7 Added approx. 11,000-ton electric-

driven mechanical chiller plant7 Added 193,000 ton-hours of strati-

fied chilled water TES (full loadshift)

TES-TIC Results7 TES-TIC in-service in 20047 30% enhancement in hot weather

power output7 Low unit capital cost per MW of

power enhancement7 Use of TES saved approx. 20,000 tons

of installed chiller plant capacity7 Use of TES reduced on-peak para-

sitic loads (increased net on-peakpower) by approx. 20 MW

7 Use of TES saved approx. $10 mil-lion in capital cost versus a non-TESTIC chiller system

SummaryNo one technology is universally best

for all TIC applications. TES-TIC sys-tems are being increasingly applied, par-ticularly where the value of electricpower varies significantly as a function oftime-of-day on hot weather days. Of allavailable TIC technologies, TES-TIC sys-tems provide the maximum hot weatherCT power enhancement during on-peakperiods. TES-TIC also offers significantreductions in total capital cost and in unitcapital cost per MW of on-peak powerenhancement, compared to non-TESchiller systems for TIC. TES is an optionthat should be considered and exploredwhenever maximized on-peak hot weath-er performance is desirable.

NOTE: This column was edited fromits original format. Read the column in itsentirety at www.turbineinletcooling.org,where you will also find: a table outlininggeneralized characteristics of TES tech-nologies; a table analysis of recent TIC-TES installations; and an additional tech-nology case study on Combined Cooling,Heat & Power.

John S. Andrepont is the founder and president of The CoolSolutions Company, Lisle, Ill., and has 30 years of experience inenergy technologies, including various turbine inlet cooling proj-ects and over 100 thermal energy storage installations. CoolSolutions provides consulting services related to TIC, TES, andDistrict Cooling systems. He is the current chairman and directorof the Turbine Inlet Cooling Association (TICA).

Table 2: Analysis of Database of Recent TIC-TES InstallationsData Range Data Averages

First year in service 1988 to 2004

Location N. Amer./Europe/MidEast/SE Asia

Plant type SC a& CC

Number of CTs 1 to 10 3.2

CT OEM GE, SWPC, Turbomeca & others

CT plant capacity (ISO) 1 MW to 750 MW 170 MW

TIC enhancement 16% to 42% 27%

Design ambient air temp 90° to 122°F 100°F

Design TIC air temp 40° to 55°F 46°F

TIC load 30 to 30,000 tons 6,800 tons

Chiller plant capacity 380 to 16,800 tons 4,900 tons

TES discharge period 4 to 13 hours/day 6.5 hours/day

TES type ice, chilled water, low temp fluid

1988-1995 predominantly dynamic ice

1996-2004 predominantly chilled water

TES design cycle daily & weekly

1988-1995 predominantly weekly

1996-2004 predominantly daily

TES capacity 3,500 to 193,000 ton-hrs 70,000 ton-hrs

Hybrid SystemsDepending on the power plant design

and its load characteristics, a mix of TICtechnologies might provide better econom-ics than any one of the individual technolo-gies. Some of the hybrid systems that havebeen successfully used include mechanicaland absorption chillers, mechanical chillersand TES, absorption chillers with TES, andmechanical and absorption chillers withTES.

There are some hybrid systems thatare technically possible, but economicallyundesirable. Examples of such systemsinclude, initial cooling by wetted media orfogging followed by further cooling withchillers or TES. It might appear attractiveto consider cooling the inlet air first byusing wetted media or fogging becausethese are the lowest capital cost optionsand then use chillers or TES to further coolthe air down to the desired lower tempera-ture. However, such hybrid systems areeconomically unattractive. The explanationfor this is discussed in the full version ofthis column at www.energy-tech.com andwww.turbineinletcooling.org.

Using wetted media or fogging aftercooling the inlet air by chillers or TES alsois not advisable because the air exiting thecooling coils of the chiller systems wouldbe at or near saturation with very little orno scope for further cooling by evaporation.

However, if a power plant initially hada fogging system and later on decides toinstall a chiller system to meet increaseddemand, the fogging does not have to beremoved. This type of hybrid system willprovide the plant owner the flexibility touse only the fogging system when it is ade-quate to meet the power demand and usechillers only when the demand exceeds thepower output possible with the foggingsystem.

Technical ConsiderationsFavoring Hybrid Systems

A 316.8 MW cogeneration plantlocated in Texas consists of three gas tur-bines, each with a rated capacity of 105.6MW. It produces steam as a coproduct

that is sold to an adjacent chemical powerplant. The plant was originally built in1982 and a fogging system was added toit at a later date for cooling the turbineinlet air. In 1998, plant managementdecided to consider other TIC options forincreasing the power output of the plantto increase their revenues from the sale ofelectric power during on-peak period of10 hours per day.

On the basis of the typical annualhourly weather data for the plant location,the maximum cooling load for the plantwas estimated to be 20,830 TR for coolingthe inlet air to 50°F. However, the dry-bulbtemperature and the coincident wet-bulbtemperature corresponding to that coolingload occur for only one hour in a year. Indiscussions with the plant management, itwas decided that the total TIC capacity of18,400 TR would be acceptable. This cool-ing capacity would be adequate for nearly99 percent of the typical annual weatherdata.

Since the cogeneration plant could sellall the steam it could produce at an attrac-tive price, the option of using steam-heatedabsorption chillers and steam turbine-driv-en mechanical chillers were not desirablefor this plant. As the power plant ownerswanted to market maximum power duringthe on-peak period, an electrically drivenmechanical chiller was not believed to bethe preferred option for TIC.

Because the power plant had highpower demand only during on-peak period,it was planned to use TIC only during theon-peak period. Therefore, the use of TESwas considered imperative in order to mini-mize the installed capacities of the chillers.

The temperature of the exhaust gasfrom the existing heat recovery steam gen-erator (HRSG) was 340°F. An analysis ofthe HRSG exhaust gases showed that thesegases could be cooled to 286°F withoutcausing condensation. Further analysisshowed that cooling these exhaust gasescould produce enough hot water to operatea hot water heated, single effect (HWSE)absorption chiller with a maximum capaci-ty of 8,300 tons of refrigeration (TR).

A detailed analysis of the coolingcoil design for the TIC system showed

that the optimum temperature of thechilled water should be 38°F in order tofit the cooling coil in the available spacefor this retrofit application. As discussedin an earlier column, we cannot achieve38°F temperature of chilled water froman absorption chiller. The best it can do isto deliver chilled water at 41°F and thechiller would require some derating of itsrated capacity (at standard chilled watertemperature of 44°F). Therefore, it wasdecided that we would have to use anelectric driven mechanical chiller to coolthe chilled water at 41°F, from the HWSEabsorption chiller, to the desired tempera-ture of 38°F. The capacity of such achiller was estimated to be 1,200 TR.

As total chilling capacity required dur-ing the on-peak period was estimated to be18,400 TR and the two chillers could sup-ply only a total of 9,500 TR, the balance8,900 TR must be planned to come fromthe TES system. Since the total on-peakperiod is for 10 hours, the TES capacityshould be at least a 89,000 ton-hr.Therefore, the hybrid system for the plantthat might be the optimum for the subjectcogeneration plant would consist of a8,300 TR HWSE absorption chiller, a1,200 TR electric-driven mechanicalchiller, and a 89,000 ton-hr TES system.Additional options for hybrid systems forthis plant and the economics of some of theoptions are available in the full version ofthis column at www.energy-tech.com andwww.turbineinletcooling.org.

LNG-Based TICThere are several LNG terminals

across the U.S. where natural gas is storedas a liquid or LNG is imported from over-seas in tankers. The LNG terminals areused as a resource to meet peak demandsof natural gas. With the current high pricesof natural gas many energy companies areconsidering and installing additional LNGfacilities in the U.S. and elsewhere. Theoff-loading of LNG from a tanker into anatural gas pipeline and/or for use in apower plant requires the re-vaporization ofthe natural gas. LNG in its liquid state is at-258°F. Therefore, it can be converted

Hybrid Systems & LNG for Turbine Inlet Cooling (TIC)Dharam V. Punwani

COOL YOUR JETSAppeared in October 2004 Energy-Tech Magazine

18

COOL YOUR JETS

19

Appeared in October 2004 Energy-Tech Magazine

readily into the vapor phase with low-levelheat. LNG vaporization systems can utilizesteam or hot water generated from naturalgas fired heaters, seawater, or ambient air.A typical 2 billion SCF per day LNG facil-ity requires 1,114 MMBtu/hr of heat tovaporize the LNG. Therefore, if turbineinlet air is used to provide that heat, it willachieve over 92,800 tons of cooling.

At 95°F dry-bulb temperature and 48percent relative humidity, a GE Frame 7FAgas turbine requires a TIC capacity ofabout 7,000 tons to cool the inlet air to45°F to boost its power output from 147.9MW to 175.3 MW. Therefore, a typical 2billion SCF per day LNG plant can provideTIC for as many as 13 GE Frame 7FA gasturbines and boost their total output by 356MW, an 18.5 percent increase in capacityfrom the uncooled system at 95°F. The costof TIC to the power plant owners could benegotiated with the owners of the LNGplant.

For an existing LNG system using nat-ural gas derived heat, TIC would eliminatethe consumption of 1,392.5 MMBtu/hr ofnatural gas (assuming 80 percent boiler effi-ciency) to vaporize LNG. This is a saving of

$9,000 per hour in natural gas (assuming acost of $6.50/MMBtu) and for systemsusing seawater or ambient air derived heat,TIC would capture valuable refrigeration(that is otherwise lost), increase power plantoutput and increase the vaporization systemcapacity. Most likely the combustion turbinebased power plant will not be of the sizeillustrated above but the relative savings willstill hold true.

Consideration should be given to thesiting of a cogeneration facility at the LNGplant to provide an efficient source of LNGvaporization energy. As an example, a sin-gle GE Frame 7FA combustion turbinewith a heat recovery steam generator(HRSG) and duct burner could readily pro-duce the steam required to vaporize the

remaining LNG not vaporized by the TICsystem. The cogeneration plant could pro-vide lower cost power to the LNG facilitywhile exporting the remainder to a thirdparty under a power purchase agreement(PPA) or the wholesale electric market.The savings on retail electric purchases andrevenues from electric sales should justifythe capital expenditure of the cogenerationplant while reducing the cost of LNGvaporization.

NOTE: This column was edited fromits original format. Read the column in itsentirety at www.turbineinletcooling.org,where you will also find more informationabout Hybrid Systems, its Economics, andsupporting graphical data.

Dharam V. Punwani is president of Avalon Consulting, Inc. locatedin the Chicagoland area (Naperville), and has over 36 years of expe-rience in energy technologies. Avalon provides technical and eco-nomic analyses related to TIC and cogeneration systems. He waschairman of TICA in 2002 and now serves as its Executive Director.

The Turbine Inlet Cooling Association (TICA) brings together partiesinterested in the benefits of turbine inlet cooling (TIC). The TICA mis-sion is to promote the development and exchange of knowledge relat-ed to TIC, for enhancing power generation worldwide, and to be thepremier one-stop source of information on TIC.

TICA membership provides benefits to: power plant owners/opera-tors, plant EPCs, turbine OEMs, TIC system & component suppliers,contractors, consultants, and interested individual professionals &associations.

See how TICA can benefit you. Join with some of our current members:

Avalon Consulting u Axford Turbine Consultants u Baltimore Aircoil Company uChicago Bridge & Iron u Cool Solutions u FES Systems u Kohlenberger Associates uMarley Cooling Technologies u Munters u South-Port Systems u The Stellar Group uStrategic Energy Services u Trane u Turbine Air Systems u Weir Techna u YorkInternational

Visit www.turbineinletcooling.orgOR CALL 630-357-3960 (FAX 630-357-1004)

NoCooling

WettedMedia

Fogging Chillers

Capa

city

Enha

ncem

ent,

MW

NoCooling

Chillers Fogging WettedMedia

Incr

emen

talC

apita

lCos

t,$/

kW

Recapture lost hot-weather power output . . .FOR A FRACTION THE $/MW OF CONVENTIONAL PLANTS!

Turbine Inlet Cooling (TIC)INSTALLATION SUCCESS STORIES

IntroductionNumerous success stories portray the

benefits of TIC installations. The examplesdescribed here serve to illustrate the verybroad scope of applications. Specifically,they cover:

t Power plant capacities from 1 MWto 750 MW

t Simple-cycle and combined-cycleapplications

t New construction and retrofit situa-tions

t Electric utility and independentpower/District Energy/DistributedGeneration owners

t Electric motor-driven, absorption,steam turbine-driven, and hybridchiller plants

t Real-time (or “on-line”) chilling andThermal Energy Storage (TES) sys-tems

t Locales including FL, IL, NY, OK,and the Middle East/Persian Gulfregion

t Systems operating for more than 10years and others just coming on-line

ABSORPTION COOLING

Trigen Energy Corporation

Nassau County, New YorkA District Energy system in Nassau

County, Long Island, N.Y., serves variedpublic and private sector thermal energy

users (a large community college, medicalcenter, sports coliseum, hotel, museumcomplex, etc.) with heating and cooling.The central Combined Heat & Power(CHP) plant comprises:

t A nominal 57 MW of electric powerin a CT Combined Cycle (CTCC)n 42 MW from the CTn 15 MW from the steam turbine

t 267 MWt of steam heatt 16,400 tons of chilled water coolingA TIC system was retrofitted to the

existing CTCC in the winter of 1996/97.The 1991 GE MS6001B CT was fittedwith three banks of six chilled water(CHW) coils each in the inlet filter house.Coil design allowed inlet air with drybulb/wet bulb temperatures of 92°/76°F(33°/24°C) to be cooled to 46.5°F (8°C),using CHW supply and return temperaturesof 43°/60°F (6°/16°C). Design airflow was240,000 cfm for a cooling load of 1,880tons. Airside pressure drop was limited to1.5 inches of water column (for the coilsand the ducting) in order to minimize thenegative impact of inlet air pressure losseson the CT power output. Simultaneouslywith the coil installation, a new 1,200 tonsingle-stage Lithium-Bromide and waterabsorption chiller was added to the existing15,200 tons of steam turbine-drivenchillers. (The mismatch in cooling coilload and chiller capacity was not an issuedue to some excess installed cooling capac-ity in the existing chiller plant.)

The 1997 results exceeded expecta-tions. Inlet air temperature was maintained

at 46°F (8°C) during a period of 98°F(37°C) ambient dry bulb air temperature.CT power output was increased by approx-imately 8 MW (a 23.5 percent increase).And CT heat rate was improved by approx-imately 5 percent. As an added benefit,condensate run-off is collected from theinlet cooling coils and used for coolingtower make-up in the District Coolingplant.

Total project installation costs were$809,000 for the TIC portion and $671,000for the absorption cooling addition. Simplepayback for the project was slightly overthree years. Total unit capital cost was$185 per kW of incremental power output,well below half the installed unit cost ofnew simple cycle CT capacity (typically$400 to $500 per kW). Of course the over-all project economics were aided by thepresence of the existing District Coolingplant equipment (without which, largerabsorption chiller capacity and new coolingtower capacity would also have beenrequired).

MECHANICAL COMPRESSIONREFRIGERATION

Trigen Energy Corporation

Chicago, Oklahoma City,Tulsa, Okla.

District Energy (heating and cooling)systems in Chicago, Oklahoma City, andTulsa each utilize one or more 1 MW

20

Trigen, Nassau County, N.Y. Photo courtesy of Trigen Energy Corporation

21

Turbomeca Makila TI (helicopter enginederivative) CTs as key elements in theirCHP systems. There are three CTs in theChicago application (1997) and one each inthe Oklahoma City and Tulsa applications(1993). CT power output in each case isenhanced through the use of TIC.

The CTs are each on a common shaftwith not only an induction motor/generator,but also a 2,000-ton ammonia screw chillerthat is one component of the larger DistrictCooling plant. A side stream of ammoniarefrigerant is evaporated in a coil located inthe inlet air stream to the CT, thus provid-ing the desired inlet air cooling and CTpower enhancement.

Using TIC to cool the inlet air to 50°F(10°C) enhances power output by 33 per-cent or more on the peak design day. Ineach of these three installations, the cool-ing duty for the TIC system is only a frac-tion of one percent of the total DistrictCooling system capacity. Accordingly, itwas a simple and economical matter to addthe inlet air coil and interconnecting refrig-erant lines, with virtually no impact on theoverall cooling system design, thus captur-ing the CT power output increase at verylow capital cost.

THERMAL ENERGYSTORAGE (TES) & HYBRIDCHILLER PLANT

Walt Disney World/ReedyCreek Improvement District

Lake Buena Vista, Fla.A District Energy system outside

Orlando, Fla., serves the world-renownedWalt Disney World entertainment complexwith heating, cooling, and electric power

(Clark, 1998). The central CHP plant comprises:

t A nominal 40 MW of electric powerin a CTCCn 32 MW from the CTn 8.5 MW from the steam turbine

t 90,000 pounds/hour of steam from aHRSG (for HW District Heating andabsorption chillers)

t 14,425 tons of chilled water cooling(absorption and, primarily, electriccentrifugal chillers)

A TIC system was retrofitted to theexisting CTCC in 1997/98. The existingGE LM5000 CT was fitted with four banksof CHW coils in the inlet filter house. Coildesign allowed inlet air with dry bulb/wetbulb temperatures of 95°/79°F (35°/26°C)to be cooled to 50°F (10°C), using CHWsupply and return temperatures of 40°/70°F(4°/21°C). Design airflow was 219,200cfm. Air-side pressure drop was limited to1.2 inches of water column (across thecoils only) in order to minimize the nega-tive impact of inlet air pressure losses onthe CT power output. Simultaneously withthe coil installation, a new 57,000 ton-hourstratified CHW TES tank was added to theexisting 17,750 tons of electric and absorp-tion chillers. (The addition of the TEScapacity was sufficient, not only to meetthe new load associated with the TIC sys-tem, but also to eliminate the need for twonew chillers of 3,325 tons capacity thatwould otherwise have been required toreplace aging, inefficient, CFC refrigerantchillers that were retired when the TESsystem was added. Even without those twonew chillers, excess nighttime chiller plantcapacity is adequate to meet nighttimecooling loads and to charge the TES tankfor use the next day in meeting peak loadsin both the District Cooling system and inthe TIC system.)

CT power output is increased by up to8 MW (more than a 30 percent increase) inextreme weather conditions, from 26 MWat 95°F (35°C) to 34 MW at 50°F (10°C).And CT heat rate is also improved byapproximately 6 percent.

The 5 million gallon (19 million liter)stratified CHW TES reservoir is an insulat-ed, above ground, welded-steel storagetank, 116 feet (35.4 m) in diameter and 67feet (20.4 m) high. The 57,000 ton-hourcapacity provides 2,000 tons for TIC and3,500 tons for the District Cooling system,for up to 10 hours per day. Design CHWsupply temperature is 40°F (4°C) for bothsystems, with CHW return temperatures of70°F (21°C) for the TIC system and 55°F(13°C) for the District Cooling system.

Although actual project economics arenot available for publication, the TIC-TESproject achieved the following results:

t Up to an 8 MW (over 30 percent)increase in on-peak CT power out-put

t A 12 MW reduction in on-peakpower purchases

t Elimination of the need for 3,325tons of new chiller plant capacity

t Operating energy savings providingan attractive rate or return on theinvested capital

t A Net Present Value (NPV) for theproject totaling several millions ofdollars.

Utility Power Plant

Middle East/Persian Gulf RegionAn existing electric utility power plant

in the Middle East/Persian Gulf region isbeing retrofitted with TIC. The applicableportion of the plant comprises 10 CTs,each a nominal 75 MW, in simple cycleconfiguration. The TIC system installation

Exira station, loccated in the Midwest. Photo courtesy of TAS, Ltd.An inlet chilling system allows the facility to operate at peak outputand efficiency year round. Photo courtesy of TAS, Ltd.

22

is nearly complete, with TIC operationsscheduled to commence in 2005.

The existing GE Frame 7EA CTs arebeing fitted with cooling coils. Coil designwill allow inlet air with a dry bulb temper-ature of 122°F (50°C) to be cooled to54.5°F (12.5°C). Design cooling load isapproximately 3,000 tons at each of the 10CTs. Air-side pressure drop is limitedacross the coils and ducting in order tominimize the negative impact of inlet airpressure losses on the CT power output.

A combination chiller plant and TESsystem have been installed to provide thecooling. The chiller plant employs thepackaged plant approach and uses electricmotor-driven chillers and, due to the highvalue of water resources in the region, air-cooled condensers for the R-134a refriger-ant. The stratified CHW TES reservoir isan above ground, welded-steel tank, whichis charged during 18 non-peak hours perday and discharged during the six hours ofpeak power demand per day. The 193,000ton-hour TES capacity provides 30,000tons of cooling for TIC, for six hours perday, minimizing parasitic power consump-tion, and maximizing net power plant out-put, during the period of peak power value.

Net power plant output is guaranteedto be increased by 30 percent in the designday weather conditions. CT heat rate isalso significantly improved.

A very low installed capital cost wasachieved, in large part through the use ofthe packaged chiller plant approach, butmost significantly by using the TES systemto reduce the required capacity of the new

chiller plant from 30,000 tons to only11,000 tons. And by using a relatively highsupply-to-return temperature differential inthe chilled water system, the size and capi-tal cost of the TES tank (and of the CHWpumps and piping) were minimized. Thetotal project capital cost is well below halfthe installed cost of equivalent new simplecycle CT capacity (which would haverequired the addition of three more CTs).

References1. Andrepont, J.S., “Combustion Turbine

Inlet Air Cooling (CTIAC): Benefits,Technology Options, and Applicationsfor District Energy,” Proceedings of theIDEA (International District EnergyAssociation) 91st Annual Conference,Montreal, Quebec, June 2000.

2. Clark, K.M. et al., “The Application ofThermal Energy Storage for DistrictCooling and Combustion Turbine InletAir Cooling,” Proceedings of the IDEA89th Annual Conference, San Antonio,Texas, June 1998.

TURBINE INLET CHILLINGFOR COMBINED-CYCLE PLANT

Brazos Valley | Texas

Introduction

Turbine Air Systems (TAS) recentlydesigned and installed two of their F-50Cchiller packages for a 610MW power plant

located near Richmond, Texas, about 30miles south of Houston. The combined-cycle plant, originally built for NRG byBlack & Veatch, E&C contractors, and nowoperated by Brazos Valley Energy LP,includes two GE Frame 7FA gas turbine-generating sets, Heat Recovery SteamGeneration (HRSG), and steam turbine-generators, for a combined output of631MW. The project was commissioned inApril 2003 and has completed two sum-mers of successful operations.

Project DescriptionThe Brazos Valley Project has two F-

50C chiller packages tied together by anoptional “forward” pipe rack. Each F-50Cpackage is anchored by two Trane CDHF2500 “Duplex” Chillers and includes 3 x50% redundant chilled water and condens-er pumps; four cooling tower cells; forwardpipe rack manifolds; an electrical distribu-tion skid allowing a single medium voltage(4160V) feed from the customer; two setsof air inlet cooling coils; two sets of coilmanifold piping; and two sets of supplyand return riser piping. The use of TraneDuplex chillers in series provides for themost efficient chiller system in its class.Each basic chiller plant was delivered inthree self-contained pieces and installed inone week by a crew of six.

Design conditions for the plant speci-fied 93.4ºF dry bulb and 76.9ºF wet bulb,and inlet air at 56ºF (13.3ºC) with an alter-nate design point of 52ºF (11.2ºC), whichwas selected by the customer. The calculat-ed load for the chilled water system was

Photo courtesy of Turbine Air Systems

23

9,590 tons, and 11,900 tons for the chosenalternate. TAS provided a turnkey installa-tion of the chiller packages and the inlet aircoils for this project. The installation wascompleted in less than eight weeks.

Customer Added ValueThe TIC application added over 55 net

MW to the facility combined cycle output,while maintaining combined cycle heatrate. A major benefit of inlet air chilling forthis project is that the operator knows theabsolute power output AND the heat rateof the plant every single day, regardless ofambient temperature or power demandfluctuations. This provides for accuratebidding of power into the merchant marketAND reliable forecasting of natural gasusage.

In addition, at Brazos Valley, the oper-ator is using the TIC system to control totalsystem output, allowing the gas turbines tooperate at base load while handling thevariations in output by modifying the gasturbine inlet air temperature.

SummaryThis is an example of TAS’ flagship

model, the F Series system. Although thispackage was originally conceived as a“clean-sheet” design to support the F-classfleet of gas turbines, the F-Series chillermodel has become the reference standardfor all large-tonnage applications, proceed-ing to support aero-derivative projects aswell as District Cooling Applications.

TAS’ scope also included the design,provision, and installation of the cooling

coils at the filter house, including a sophis-ticated self-balancing reverse-return mani-fold and all local supply piping, with tem-

perature control valves.

Exira Station | Midwest

SIMPLE-CYCLE PEAKER PLANT

IntroductionTurbine Air Systems (TAS) recently

designed and installed a single F-50Cpackaged chiller system for a 90 MWpower plant located between Des Moines,Iowa and Lincoln, Nebraska. The simple-cycle peaker plant, built by Harris Group,and RW Beck (owner’s engineer) for amunicipal utility, includes two GELM6000PC Sprint gas turbine-generatingsets. The project was commissioned inApril 2004 and has been successfully oper-ating throughout the summer.

Project DescriptionDesign conditions for the plant speci-

fied 95.5ºF dry bulb at a 58.6 percent rela-tive humidity. The inlet chilling systemcools the inlet air to 48ºF for maximum gasturbine output and efficiency. The capacityof the chilled water system is 5,100 tons, atdesign conditions. The TAS’ F-50C pack-age is anchored by two Trane CDHF 2500“Duplex” chillers and includes 3 x 50%redundant chilled water and condenserpumps; four cooling towers cells; dualelectrical feeds from the customer; andDelta V controls. To improve off-design

efficiency, the system is supplied with vari-able frequency drives on the chilled waterpump and cooling tower fan motors. Eachbasic chiller plant was delivered in threeself-contained pieces (chillers, pumps, andelectrical controls), allowing for shorterconstruction time. TAS provided all materi-als to the site and included technical instal-lation supervision. The installation wascompleted in approximately five weeks.

Customer Added ValueThe TIC application added over 15 net

MW to the facility’s output, while improv-ing the facility heat rate by over two per-cent. A major benefit, in addition to the 20percent increase in output, of inlet air chill-ing for this project is that the utility knowsmonths in advance the exact power outputand heat rate for the plant, regardless ofany day’s temperature or special weatherconditions (humid, dry, etc.). This providesfor accurate planning of power productionas well as better forecasting the municipalutility’s need to purchase power from themarket. The ability to know these exactconditions also allows the owner to makebetter long-term purchases of natural gas.

SummaryThis is an example of TAS’ flagship

model, the F Series system. Although thispackage was originally conceived as a“clean-sheet” design to support the F-classfleet of gas turbines, the F-Series chillermodel has become the reference standardfor all large-tonnage applications, proceed-ing to support aero-derivative projects aswell as District Cooling Applications.

EVAPORATIVE COOLING FORCOGENERATION PLANT

Hunts Bay Power Station |Kingston, Jaimaica

IntroductionThe Hunts Bay Power Station is a 668-

megawatt (MW) combined-cycle cogenera-tion power plant located in Kingston,Jamaica. The plant is owned by JamaicaPublic Service Company Ltd.

The Hunts Bay facility includes threecombustion turbines: two GT Browns andone GE Frame 7. They needed to improveplant operations and increase output andefficiency in order to recover power and

Photo courtesy of Turbine Air Systems

24

generate greater revenue. In addition,nitrous oxides and carbon monoxide emis-sions must be continuously monitored andcontrolled at the facility with minimal envi-ronmental impact. Installation of an evapo-rative cooling system increased power out-put by 2.4 MW.

Project DescriptionThe average annual growth in demand

for electricity in Jamaica over the past 10years was approximately 5 percent and theforecast for the next five years is 6 per-cent/annum.

“It was expected that by the years2003 and 2004 the demand will have sur-passed our generating capacity,” said DaveStamp, Facility Engineer for Hunts BayPower Station.

A gradual reduction in capacity isexpected with increased ambient tempera-ture, hence in Kingston, with high ambienttemperatures of 90º-92ºF in the summermonths, only approximately 85 percent ofISO MCR can be realized.

It was with this in mind that JamaicaPublic Service Company Ltd. investigatedways to increase the capacity of its gener-ating units. One such method utilizes evap-orative cooling technology to cool the inletair to the gas turbine.

The SolutionIn order to prove the suitability of the

inlet air cooling technology to theJamaican climatic conditions, a pilot proj-ect was conceived. Gas Turbine no. 4, aJohn Brown Engineering MS5001 (Frame5) unit with an ISO rating of 25.5 MW[59ºF and 14.7 pounds per square inchabsolute (psia) inlet air] and a site rating of21.750 MW (88°F and 14.7 psia), wasselected.

There were several reasons Hunts Baychose to use an evaporative cooling systemat the plant versus other cooling methods:ease of retrofit installation, low operatingcost, and low inlet pressure drop.

The pilot test was conducted for sixmonths, from January through June 2000.The results of the test proved that HuntsBay Power Station benefited from theinstallation of the evaporative cooling sys-tem.

SummaryThe Hunts Bay Power Station regained

as much as 10 percent of the power capaci-ty with the addition of the evaporativecooling unit.

Benefits:t Increased Power Output: The maxi-

mum load achieved during the testwas 24.6 MW at 88ºF. This repre-sents an increase of 2.4 MW.

t Reduced Pressure Drop: The oldinlet filters were removed andreplaced with the evaporative cooler,which resulted in a much lower pres-sure drop.

t Reduction in Heat: An averagereduction in heat rate of 1.6 percentwith annual savings of $40,857.00.

t Low Maintenance: The evaporativecooling system is low in mainte-nance.

This success story was submitted byMunters Corporation.

Kalaeloa Cogeneration PlantKalaeloa, Hawaii

COMBINED-CYCLE PLANT

IntroductionKalaeloa Cogeneration Plant is a com-

bined-cycle combustion turbine facilitylocated in Kapolei, Hawaii. As a partner-ship between ABB Energy Ventures andKalaeloa Investment Partners, the cogener-ation plant provides a portion of the steamneeds for Tesoro Hawaii Corporation, oneof the two oil refineries in the state ofHawaii, as well as 180 MW of firm capaci-ty net electrical power to Hawaiian ElectricCompany.

The combined-cycle plant designincludes two ABB 74.6 MW type 11N gasturbines, one ABB 51.5 MWextraction/condensing steam turbine, andtwo Deltak heat recovery steam generators(HRSG), plus a balance of equipment thatcompletes the combined cycle.

Project DescriptionKalaeloa Partners L.P. decided to

examine the plant’s system design todetermine what capital upgrades could beimplemented to increase plant output andefficiency. They found that an evaporativecooling system was one such upgrade thatcould do just that.

The cleaner and cooler the air takeninto the turbine, the more efficiently theturbines operate, resulting in a higherpower output. Conversely, as the air inlettemperature rises, power output falls andefficiency decreases.

Kalaeloa Partners knew they couldrecover lost power by cooling intake airbefore it enters the gas turbine. That iswhen Kalaeloa contacted a few evapora-tive cooling manufacturers, includingMunters Corporation, Systems Division.

After careful analysis, KalaeloaPartners L.P. decided to retrofit both ofthe ABB 11N gas turbines with a stand-alone evaporative cooling systemdesigned and developed to increase out-put levels and improve thermal efficiency.This system was chosen over the othertypes of cooling systems such as foggingand air chillers because of simplicity, reli-ability, and cost. The fogging systems didnot appear to have the track record ofproducing the reliable cooling effect wewere looking for, and the air chillers arevery costly to install and operate.

Kalaeloa projected an approximate2.1 MW increase on each combustion tur-bine, for a total plant output increase of4.2 MW.

SummaryActual power increase has been higher

than anticipated - closer to a 5 MW totalincrease. In addition, they have experi-enced almost a full MW increase on thesteam turbine as well because the heatenergy in the exhaust gas increased, thusallowing the HRSG to produce more steamfor the combined cycle to take advantageof.

In evaporative cooling, intake air ispassed through one or more wet pads tosimultaneously absorb moisture and coolthe air. The cool, humid air is directed tothe area where it is needed. The installedevaporative cooling system cools the inletair, creating denser air and giving gas tur-bines a higher mass flow rate and pressureratio, thus resulting in an increase in poweroutput and efficiency.

This success story was submitted byMunters Corporation.

CALPINE CLEAR LAKECOGENERATION, INC.

Texas

IntroductionThe natural gas fired Calpine Clear

Lake Cogeneration power plant in

25

Pasadena, Texas went into operation in1982. Steam is produced and sold to anadjacent chemical plant; electricity is pro-duced and sold to the plant with excessgoing to the market. A fogging systemwas retrofitted later to increase poweroutput by turbine inlet cooling. To furtherincrease the plant’s reliability and capaci-ty for selling additional electric energyduring “on-peak” periods, the plant wasretrofitted in 1999 with a turbine inletcooling system comprised of hot waterdriven absorption chillers, one electricchiller, and a chilled water thermal ener-gy storage system.

Project DescriptionThe cogeneration plant operated with

three W501D’s combustion turbines, eachof 105.6 MW rated capacity, with totalrated capacity of 316.8 MW before theplant was retrofitted in 1999. The retrofitincluded installation of a hybrid refrigera-tion system including five absorptionchillers (total capacity of 8,300 TR) andone electric chiller (1,200 TR); one184,000 ton-hr (6.5 mill gallon) capacitythermal energy storage tank, custom builtfilter houses with cooling coils; and aheat recovery coil retrofit.

The gas combustion turbine inlet aircooling system was designed to cool theambient air from 95°F dry-bulb/80°F wet-bulb temperature to a 50°F combustionturbine inlet air temperature.

The turbine inlet chilling system alsoutilizes thermal energy storage. The sys-tem is designed to produce and storechilled water energy during 14 “night-time, off-peak” hours and discharge theenergy to cool the air during 10 “on-peak” hours of the day to supplement the

chillers during the on-peak period. This“partial-storage” design not only reducesthe amount of chillers needed but alsoreduces the on-peak steam and powerconsumption. During operating periodswhen the ambient temperatures are lessthan design, the air can be cooled to tem-peratures slightly lower than 50°F oralternately the 50°F temp can be main-tained for longer than the 10 hr designperiod per day.

Customer Added ValueThe TIC application added over 51 net

MW to the facility’s output on the hot day(95°F dry-bulb/80°F wet-bulb temperature)while improving the “on-peak” heat rate byapproximately 3.5 percent. A major benefit,in addition to the increase in output for thisproject, is that Calpine uses waste heatwhich otherwise would be exhausted to theatmosphere to produce additional “sell-able” power during “on-peak” hours of theday. In addition, the colder inlet air temper-ature increases the mass flow of the airthrough the gas turbine which results inmore cogen steam produced and availablefor export.

SummaryThe owner of this facility has com-

bined multiple strategies includingabsorption chillers in series with mechan-ical chilling combined with thermal ener-gy storage to optimize operator flexibilityand increase “dispatchable” power. Theoutput and heat rate for the plant isknown in advance, regardless of anyday’s temperature or special weather con-ditions (humid, dry, etc.) to take weathervariability out of the production equation.This provides for accurate planning of

power production as well as better fore-casting of power for sale to the market.

Thermal energy storage increases theflexibility and predictability by the opera-tor compared to “on-line” systems, thework of the refrigeration system is doneprior to need and the full value of thewaste heat is utilized 24hrs/day. In addi-tion, using nighttime hours to store ther-mal energy reduces plant emissions.Think “green.”

The stories onpages 20-22 weresubmitted by John S.Andrepont, founderand president of TheCool SolutionsCompany, Lisle, Ill.John has 30 years of

experience in energy technologies,including various turbine inlet coolingprojects and over 100 thermal energystorage installations. Cool Solutionsprovides consulting services related toTIC, TES, and District Cooling sys-tems. He is the current chairman anddirector of the Turbine Inlet CoolingAssociation (TICA), www.turbineinlet-cooling.org.

Pictured are just a few of the downtown Tulsa buildings served by theTrigen-Tulsa plant. Photo courtesy of the Trigen Energy Corporation

Pictured is the Middle East/Persian Gulf TIC-TES system. Photo courtesy of the Stellar Group.

26

H Avalon Consulting Inc., (TICA Founding Member)427 Prairie Knoll Drive, Naperville, Illinois 60565

Dharam (Don) Punwani, Principal ConsultantPhone: 1-630-983-0883

Fax: 1-630-357-1004E-mail: dpunwani@avalonconsulting.com

Website: www.avalonconsulting.comCorporate TIC Capabilities, Products, or Services: Avalonprovides technical and economic analyses related to TICand cogeneration systems.

H Axford Turbine Consultants LLC1108 Nicholson Street, Houston, TX 77008Mark Axford, President & Chief Turbine Guru

Phone: 1-713+-802-9654E-mail: maxfordi@attglobal.net

Website: www.axford.usCorporate TIC Capabilities, Products, or Services: AxfordTurbine Consultants provide a number of services relatedto turbine based power plants.

H Baltimore Aircoil Company (TICA Founding Member)P.O. Box 7322, Baltimore, MD 21227Frank J. Bowman, Jr., VP Marketing & Support

Phone: 1-410-799-6496Fax: 1-410-799-6346

E-mail: fbowman@baltimoreaircoil.comWebsite: www.baltimoreaircoil.com

Corporate TIC Capabilities, Products, or Services: BaltimoreAircoil Company (BAC) is a worldwide manufacturer andmarketer of heat transfer and ice thermal storage products.

H Chicago Bridge & Iron Company(TICA Founding Member)One CB&I Plaza, 2103 Research Forest DriveThe Woodlands, TX 77380Orville A. Earhart, Business Development Manager

Phone: 1-832-513-1122Fax: 1-832-513-1505

E-mail: oearhart@cbiepc.comWebsite: www.cbiepc.com

Corporate TIC Capabilities, Products, or Services: CB&I, aglobal design-build construction company with over $1 bil-lion in worldwide annual revenues, has long served thepower industry with many quality turnkey products andservices.

H FES Systems, Inc. (TICA Founding Member)3475 Board Road, York, Pennsylvania 17402Dennis Halsey, Vice President - Sales & Marketing

Phone: 1-717-767-6411Fax: 1-717-764-3627

E-mail: dhalsey@fessystems.comWebsite: www.fessystems.com

Corporate TIC Capabilities, Products, or Services: GEA FESSystems Inc. provides a complete direct refrigeration pack-age for the pre-cooling of turbine air typically using ananhydrous ammonia (R-717) liquid overfeed arrangement.

H Kohlenberger/KACE Energy Corporation (TICA Founding Member)611 South Euclid St., Fullerton, California 92838Karl Kohlenberger, General Manager

Phone: 1-714-738-7733Fax: 1-714-738-3905

E-mail: kohlenberger@kaceenergy.comWebsite: www.kaceenergy.com

Corporate TIC Capabilities, Products, or Services:Kohlenberger / KACE Energy delivers engineering servicesto the industrial refrigeration industry offering experiencein refrigeration systems/facilities design and contracting.

H Marley Cooling Technologies, Inc.7401 W. 129th St., Overland Park, KS 66213Paul Lindahl, Dir. Marketing & Business Development

Phone: 1-913-664-7588Fax: 1-913-693-9310

E-mail: paul.lindahl@marleyct.spx.comWebsite: www.marleyct.com

Corporate TIC Capabilities, Products, or Services: Many ofthe existing turbine air inlet cooling installations use MCTproducts.

H Munters Corporation (TICA Founding Member)108 6th Street, S.E., Ft. Myers, Florida 33907Brian Simmons, Turbine Inlet Sales Manager

Phone: 1-919-367-9160Fax: 1-509-355-9651

E-mail: brian_simmons@munters.comWebsite: www.muntersamerica.com

Corporate TIC Capabilities, Products, or Services: Foralmost 40 years, Munters has been an authority on evapo-rative cooling technology.

H Parker Hannifin Corp., Gas Turbine Fuel SystemsDivision (TICA Founding Member)9200 Tyler Blvd., Mentor, Ohio 44060Kim Aiken, Senior Support Engineer

Phone: 1-630-553-8440Fax: 1-630-553-8440

E-mail: macrospray@parker.comWebsite: www.parker.com, www.macrospray.com

Corporate TIC Capabilities, Products, or Services: ParkerHannifin is the world’s leading supplier of motion and con-trol equipment.

H South-Port Systems, Inc. (TICA Founding Member)900 Central, Houston, Texas 77012 USAJim Landers, President

Phone: 1-713-926-6005Fax: 1-713-926-7358

E-mail: jlanders@spsincusa.comCorporate TIC Capabilities, Products, or Services: South-Port Systems, Inc. has been in the packaging businesssince 1973.

H Strategic Energy Services, Inc. (TICA Founding Member)430 Trend Road, Yardley, Pennsylvania 19067 USARaymond M. Pasteris, President

Phone: 1-215-736-8170Fax: 1-215-736-8171

E-mail: rpasteris@strategicenergy.comWebsite: www.strategicenergy.com

Corporate TIC Capabilities, Products, or Services: STRATE-GIC ENERGY SERVICES, INC. located midway betweenPhiladelphia and New York City operates as a unique ener-gy firm providing energy development, engineering, eco-nomic and commercial services in district heating andcooling, combined heat and power (“CHP”), turbine inletair cooling, energy conservation audits, energy asset valu-ation and energy performance contracting.

H The Cool Solutions Company(TICA Founding Member)5007 Lincoln Avenue, Suite 201, Lisle, Illinois 60532John S. Andrepont, President

Phone: 1-630-353-9690Fax: 1-630-353-9691

E-mail: CoolSolutionsCo@aol.comCorporate TIC Capabilities, Products, or Services: The CoolSolutions staff provides consulting services for both thebusiness and technical aspects of CTIC developments ofvarious types, from analysis and planning through installa-tion and operation.

H The Stellar Group (TICA Founding Member)2900 Hartley Road, Jacksonville, Florida 32257 USA

Mike Solms, Vice President of Business DevelopmentPhone: 1-904-260-2900 ext. 3295

Fax: 1-904-899-9295E-mail: msolms@thestellargroup.com

Website: www.thestellargroup.com Corporate TIC Capabilities, Products, or Services: TheStellar Group provides turnkey turbine inlet chilling systemsfor aero-derivative and industrial turbine power plants.

H The Trane Company3600 Pammel Creek Road, LaCrosse, Wisconsin 54601Mike Thompson, Marketing Manager

Phone: 1-608-787-4634Fax: 1-608-787-2204

E-mail: mthompson@trane.comWebsite: www.trane.com

Corporate TIC Capabilities, Products, or Services: The TraneCompany is a worldwide leading supplier of commercialand industrial air conditioning systems, with current annualsales approaching $4 billion.

H Turbine Air Systems, Ltd. (TICA Founding Member)4300 Dixie Drive, Houston, Texas 77021 USAGary Hilberg, Vice President Sales

Phone: 1-713-877-8700Fax: 1-713-877-8701

E-mail: sales@tas.comWebsite: www.tas.com

Corporate TIC Capabilities, Products, or Services: TurbineAir Systems is the leading supplier of packaged inlet cool-ing solutions for new and existing gas turbine facilities.

H Weir Techna9802 FM1960 Bypass, Suite 200, Houston, Texas 77338 Paul Choules, Regional Vice President - Americas

Phone: 1-281 446 1273Fax: 1-281 446 3952

E-mail: p.choules@weir.co.ukWebsite: www.weirtechna.com

Corporate TIC Capabilities, Products, or Services: WeirTechna has been providing engineering solutions for morethan a century.

H York International (TICA Founding Member)11750 Clay Road, Houston, Texas 77043-1179Bill McAuliffe

Phone: 1-832-204-9435Fax: 1-832-204-9436

E-mail: bill.mcauliffe@york.comCorporate TIC Capabilities, Products, or Services: York is afortune 500 corporation founded in 1874 with headquar-ters in York, Pennsylvania that provides Industrial Electriccentrifugal chillers, Absorption chillers, Steam turbine Drivechillers and gas engine drive chillers to the Power industryand the industries leading packagers.

Turbine Inlet Cooling Buyers Guide