Practical Developments inSensible Heat, Diurnal

Cool Thermal Energy Storage (TES):Large Applications, Low Temps, Energy

Efficiency, and Operating Plus Capital Savings

John S. Andrepont, PresidentThe Cool Solutions Company

ECOSTOCK 2006ECOSTOCK 2006Absecon, New Jersey, U.S.A. Absecon, New Jersey, U.S.A. -- June 1, 2006June 1, 2006

Outline

• Introduction• Practical, Commercial Trends:

– Large Applications– Low Temperatures– High Efficiency– Capital Savings

• Case Histories with Economics• Observations and Conclusions

Nomenclature

CHP - Combined Heat & Power (cogen)CHW - Chilled WaterDC / DE - District Cooing / District EnergyLTF - Low Temperature FluidNPV - Net Present ValueTES - Thermal Energy StorageTIC - Turbine Inlet Cooling

Introduction to Diurnal Cool TES• Already, a long history of commercial

success, in varied applications:– Private commercial / industrial– Public / institutional– Thermal / electric power utilities

• Recent Trends in Diurnal Cool TES:1. Very large capacities2. Lower supply temperatures3. High energy efficiency vs non-TES systems4. Capital cost savings vs non-TES systems

Comparisons of TES Technologies• TES Technologies include:

– Latent Heat TES – Ice storage – Energy is stored as a phase change. Water is frozen in off-peak times and melted for cooling during peak times.

– Sensible Heat TES – stratified chilled water (CHW)or Low Temp Fluid (LTF) storage – Energy is stored as a temperature change. Water or fluid is chilled in off-peak times, stored in an insulated tank, and used for cooling during peak times.

• Each TES technology has inherent advantages and limitations, and many successful appl’ns.

• Understanding those attributes is important to applying TES for maximum value.

Extensive Use of TES in HVAC

• Diurnal Cool TES is already widely used:– Latent Heat TES (Ice) – thousands of

examples, averaging ~2,500 Ton-hrs (and ~300 kWe shifted) per installation

– Sensible Heat TES (CHW and LTF) –hundreds of examples, averaging ~20,000 Ton-hrs (and ~2 MWe shifted) per installation

Large Scale Applications

• Capital cost must be reasonable• Large applications should have

economy-of-scale; thus, low unit costs• Ice TES (modular equip) has little

economy-of scale, suits small appl’ns• Sensible heat TES (LTF and especially

CHW) have very low unit costs in large applications

Some Very Large Applications of Sensible Heat, Diurnal, Cool TES

TES Owner/Operator – Location TES Type Ton-hours

Florida State Univ – Tallahassee, FL 2 x CHW 55,200Reedy Creek (Disney World) – Orlando, FL CHW 57,000Univ of Alberta – Edmonton, AB CHW (LTF)* 60,000District Cooling St. Paul – St. Paul, MN 2 x CHW 65,400Daimler Chrysler – Auburn Hills, MI 2 x CHW 68,000State Farm – Bloomington, IL 2 x CHW 89,600DFW International Airport – Dallas/Ft W, TX LTF 90,000Calpine Cogeneration – Pasadena, TX CHW 107,000Chicago MPEA – Chicago, IL LTF 123,000Toyota – Georgetown, KY 3 x CHW 126,000OUCooling – Orlando, FL CHW (LTF)* 160,000electric utility – Riyadh, Saudi Arabia CHW 193,000

Capability forLow Distribution Temperatures

• Low distribution temps can yield:– smaller pumps and piping– smaller air-handlers– smaller fans and ducting– improved control of humidity and comfort

• Many (not all) Ice TES designs, as well as LTF TES, can deliver low supply temps

Some Low Temp Applications of TESTESSupply

TES Owner/Operator – Location Temp - type Ton-hrs

Climaespaco – Lisbon, Portugal +4 ºC - CHW 39,800Univ of Southern California – Pasadena +4 ºC - CHW 45,000SAWS – San Antonio, TX +2 ºC - Ice 19,400DFW International Airport – D/FW, TX +2 ºC - LTF 90,000Northwind Plant #1 – Chicago, IL +1 ºC - Ice 66,000Northwind Plant #2 – Chicago, IL +1 ºC - Ice 125,000Princeton University – Princeton, NJ 0 ºC - LTF 40,000Chicago MPEA – Chicago, IL –1 ºC - LTF 123,000

Energy Efficiency

• Recharge energy is off-peak (low cost)• Latent heat (Ice) TES has an inefficiency:

– Delta T needed to drive phase change– varying temps during charge and discharge

• Sensible heat TES (CHW and LTF)– constant discharge temps = charge temp

• Low supply temps & large Delta T improve downstream energy efficiency

Improved Energy Efficiency with TESOn-Site

TES EnergyTES Owner/Operator Type Savings Type of DataLos Angeles County CHW 15 to 25 % simulationCalifornia State Univ CHW 13 % simulationState Farm Insurance CHW 3 % simulation

Arizona State Univ CHW 13 % measuredBrazosport College CHW 8 to 9 % measuredTexas Instruments CHW 5 to 6 % measured

At source power plants (studies at 5 utilities - CA, TX, WI): TES yields 5 to 30% less fuel & emissions at the plant.

Rules-of-Thumb forAttractive TES Economics

• Capital Cost is Key– must find capital offsets, avoided by TES– economy-of-scale with large CHW / LTF TES

• Must Have Space for TES - Ice least volume– CHW TES most volume, but can be remote

• Operating Cost - important, but not dominant• Look for other synergies with TES

– comfort, flexibility, fire protection, distribution...

Some Large Capital Savings from TESTES CapitalCapacity Savings

Application – Location TES Type (Ton-hrs) (millions)

university campus – WA CHW 17,750 $1 to 2district cooling – Portugal CHW 39,800 $2.5university / hospital – Canada CHW (LTF)* 60,000 $4corporate tech center – MI 2 x CHW 68,000 $3.6International airport – CA LTF 90,000 $6convention district – FL CHW (LTF)* 160,000 over $5turbine cooling – Saudi Arabia CHW 193,000 $10

Note: Each achieved the multi-million $ capital savingsfrom TES, without any incentives from its electric utility.

TES Examples with Economics

1. Industrial Facility – Michigan2. District Energy Utility – Illinois3. District Cooling Utility – Florida4. University Campus – Washington5. Univ & Hospital Campus – Alberta, Canada6. International Airport – Texas7. Turbine Inlet Cooling – Saudi ArabiaNote: examples are quite varied –

various application types; U.S. and non-U.S. locales;hot-dry and hot-humid climate; long and short summers

Daimler Chrysler - Auburn Hills, MI

• 2M sq ft corporate technology complex• TES added during new construction• 68,000 Ton-hours stratified CHW TES• Reduced chillers from 17,700 to 11,400 T• $3.6M in net capital cost savings• 5.3 MW and ~$1M/yr in demand savings• TES serves dual-use as fire protection

Chicago MPEA - Chicago, IL

• New, expanding, DE/CHP system– 5 million sf expo center, hotel, office bldg, internet hotel

• 123,000 Ton-hour LTF TES (avoids ~19 MWe)• Delivers 30 °F supply for low temp air distribution• 24 °F Delta T + 90 ft height = only 0.5 sq ft / Ton• Can fully discharge TES in 4.9 hrs at 25,000 Tons• >21,000 T peak served with <17,000 T of chillers• Net TES capital cost of <$40/T-hr (and <$200/T)• LTF also water treatment (corrosion & microbio)

OUCooling - Orlando, FL

• 21,000 Ton DC for conv ctr and hi-tec mfg• TES added with new DC / existing chillers• 160,000 Ton-hours stratified CHW TES• Can meet 20,000 Ton load for 8 hrs/day• 10,000 Tons of new load w/o new chillers• Over $5M in net capital cost savings• 15 MW and >$0.5M/yr in oper’g savings• Expandable 56% to 250,000 T-hrs as LTF

Washington State U. - Pullman, WA

• Existing, expanding, university DC system• 17,750 Ton-hour CHW TES (avoids ~2 MWe)• Locating TES as a satellite plant peak shaves:

– CHW plant generating capacity– CHW distribution system capacity

• Net capital savings of $1 to 2 million• Operating cost savings of $260,000 per year• Possible future conversion to LTF TES

– for a >75% increase to 31,600 Ton-hours

U of Alberta - Edmonton, Alberta

• Major urban university/medical campus• TES adds system capacity, as a satellite• 60,000 Ton-hours stratified CHW TES• Can serve 29,000 T w/ <23,000 T chillers• Saved 30% (over $3M) in net capital cost• Lowers operating cost 12% (~$0.7M/yr)• ~$9M NPV of capital + 20-yr oper’g svgs• Expandable 70% to 102,000 T-hrs as LTF

DFW Airport - Dallas / Ft Worth, TX

• Major international airport• TES added during expansion / upgrade• 90,000 Ton-hours stratified LTF TES• Reduced new chillers by over 10,000 T• ~$6M in net capital cost savings• ~8 MW and ~$1M/yr in demand savings• LTF at 36 ºF used in TES & thru airport• LTF saves pipe size/hp; inhibits corr & bio

Turbine Inlet Cooling - Saudi Arabia

• 10 CT, 750 MW Gas Turbine Power Plant• TES added w/ turbine inlet cooling retrofit• 193,000 Ton-hours stratified CHW TES• Reduced chillers from 30,000 to 11,000 T• Over $10M in net capital cost savings• >20 MW extra power via TES (6 hrs/day)• TES-TIC adds 30% power; 1/2 cost of CT• TES can serve dual-use as fire protection

A Few TES Examples

ObservationsNotable TES Trends, with Numerous Examples:• Large Capacities• Low Supply Temps• Efficiency On-site and at Source Energy Plants• Large Net Capital Cost Savings, at times of:

1. New construction2. Facility expansion3. Chiller plant rehabilitation

Examples in many varied locales and climates,hot-dry, hot-humid, and long & short summers

Conclusions

• Large, sensible heat TES (CHW or LTF) is a growing commercial success.

• TES can often be the perfect fit:– It may be peak CHW generation at low $/Ton– It may enhance CHW distribution perform & econ– TES always delivers demand management.

Applied correctly, TES can capture millions in capital savings, millions more in NPV.

The trends can be expected to continue.

Questions / Discussion ?

Or for follow-up, contact:

John S. AndrepontThe Cool Solutions Company

CoolSolutionsCo@aol.comTel: +1-630-353-9690