thermal energy storage and peak load reduction mark m. maccracken, pe, leed ap, pte calmac mfg....
TRANSCRIPT
Thermal Energy Storage and Peak Load Reduction
Mark M. MacCracken, PE, LEEDAP, PteCALMAC Mfg. Corp.
Fair Lawn, NJCalmac.com
NARUC Summer Meeting 7-16-07
Benefits of Thermal Energy Storage
Reduces Peak Demand at most critical time 20-40%
Reduces consumer’s energy costs 10-20%
May reduce energy usage at the building up to 14%
Reduces source energy usage at power plant 8-34%
Reduces emissions up to 50%
Increases Load Factor of Generation up to 25%
Provides operational flexibility
Thermal Energy Storage For Off-Peak Cooling
What is it?How does it work?Why is it Green?Other “Green” AdvantagesApplications/Case Studies
Storage is Natural
Most common TES System
Water Heater (Electric)
Assume one low-flow shower
((2.5gpm x 8.33 lb/gal x (110-60))
x 60 minutes/hr / 3,414 Btu/kW = 18.3 kW
4.5 kWHeater
Gas Water Heater
Design Load = 2 Showers at a time
18.3 kW x 2 x 3414 = 124,950 Btus
East Coast of US 100,000,000 people x 25% x 1/12 Hr/shower x 18.3 kW=
38 Gigawatts = CA Electric Peak on Summer day
TES has already impacted US infrastructure
Utility Load Factors* in the USA
50
55
60
65
70
Percent
1955 1965 1975 1985 1995
Year*Load Factor = Avg. Load Peak Load
ASHRAE 90.1 Base BuildingNon-Storage Electrical Profile
Lighting
FansPumps
Base Load
Cooling
0200400600800
100012001400160018002000
k W
Total kWh = 28,000/day
Peak Load2000 kW
Avg. Load
1050 kW
(Load Factor = 53%)
Design 30% better than 90.1 Non-Storage Electrical Profile
LightingFans
Pumps
Cooling
Base Load0
200400600800
100012001400160018002000
k
WAvg. Load
800 kW
Total kWh = 19,200/day
Peak Load1500 kW
(Load Factor = 53%)
Off Peak Cooling (OPC) Electrical Profile
Base Load
LightingFans
Pumps
0200400600800
100012001400160018002000
k
W
Total kWh = 19,200/day (Load Factor = 88%)
Charging Storage
600 kW Shed600 kW Shed
Avg. Load
800kW
40% Peak Load Reduction
Peak Load 900kW
Power continue to be less expensive at Night because of Generation Load Factor
4 Buildings x 1 Megawatt4 Buildings x 1 Megawatt
= 4 Megawatts= 4 Megawatts
8,000 mW-h Sold8,000 mW-h Sold
The same generator produces The same generator produces
25% more sellable kW-h!25% more sellable kW-h!
5 Buildings with TES @ 0.8 mW 5 Buildings with TES @ 0.8 mW
= 4 Megawatts = 4 Megawatts
10,000 mW-h Sold!10,000 mW-h Sold!
3-D Electric Load Profile -- Full Year
4200 ton-hr of StorageInstalled 1990
Large Scale Sustainable Energy Future will Require Storage
1 TRILLION Watts of Generation in USA (approx.)
Costs of New Generation, InstalledCombined Cycle Gas Turbine ~ $0.50 to $1.00/WattNuclear $3.00 to $6.00/Watt
New Coal Plant $1.50/Watt New Clean Coal $2.00/Watt
Wind (30% Cap Factor ~ 0 Peak Reduction)$1.60/WattPV (30% Cap Factor ~ 15% Peak Reduction*) $7.50/ Watt
STORAGE (Thermal) $0.50 to $1.00/Watt*NREL Report
Thermal Energy Storage For Off-Peak Cooling
What is it?
How does it work?
Two Basic Systems
Water
Ice
40
56
Load
Chiller
40
40
56
Load
Chiller
40
Warm Water56 F
Cold Water40 F
Thermocline
TemperatureModulating Valve
Storage Tanks
Control Logic
Chiller Based System
Closed System
So what is “Different”?
Heat Transfer Fluid 75%H20/25%EG
Bank of America Tower at 1 Bryant Park, New York City
Bank of America / Durst Organization
History Channel “Sky Scrapers” 9-7-04
~2.2 Million ft2
Going for LEED Platinum
Thermal Storage Tank Ice-on-Coil Internal Melt
Expansion Chamber
Heat Exchanger
Tank
Insulation
Coil & Glycol25
TemperatureControl Valve
31
Ice 1000 tonOn-Peak Load
500 tonChiller
25 31
44
TemperatureControl Valve
54
Ice500 tonLoad
500 tonChiller
44
Coil & Glycol
52
TemperatureControl Valve
60
44
IceMeltedIce
Coil & Glycol
1000 tonLoad
500 tonChiller
44
34- 44
Basic Operating Modes for any Storage System
0102030405060708090
100
Time
Tons
Making Ice-Meeting LoadIce DischargeChillers Meeting LoadIce Charge
Storage System60 ton Chiller
1,100 ton-hr Storage
Load Reduction90 ton or ~ 90 kW
ICE DISCHARGE
CHILLERS
ICE CHARGE
Space?
Full Storage: 0.70% of cooled floor space
Partial Storage: Ice provides about 33% of a cooling system reducing ice tank floor space to 0.23% of cooled floor space.
Would need 25% of roof space on 100 story building!
Same ratio as the water heater in your house
1 ton cools 500 ft2
1 tank provides 20 tons1 tank cools 10,000 ft2 1 tank needs 70 ft2 (60 ft2 )
National Air and Space Museum, Washington, DC USA
Ice Storage Tanks for the entire
Project
4,700 Ton Hrs of StorageOn-Peak Chiller – 1122 TonsOn-Peak Ice Contribution – 729 Tons40% On-Peak Chiller Demand Avoided
Thermal Energy Storage Myths Article (Ashrae Journal Sept 03)
1. Uncommon2. Too Much Space3. Too Complicated4. Doesn’t Save Energy5. Too Expensive6. Lack of Redundancy (Risky)7. Rates Will Change8. Modeling doesn’t Show Results
Reality: TES is a Proven Technology
that saves Money and Energy
Thermal Energy Storage For Off-Peak Cooling
What is it?
How does it work?
Why is it Green?
Materials & Resources
Energy & Atmosphere
Water Efficiency
Sustainable Sites
Indoor Environmental Quality
LEEDTM Credits
Sustainable Sites: 14 points
Water Efficiency: 5 points
Energy* & Atmosphere: 17 points
Materials & Resources: 13 points
Indoor Environment Quality: 15 points
Innovation & Design: 5 points
69 points
*10 Energy Credit are based on ASHRAE 90.1 which is based on Energy COST Reduction
Real reasons Off-Peak Cooling is Green:
It is much more Energy Efficient to create and deliver a kWh of Electricity at night than during the hot of the day.• Research from the California Energy Commission on 2 Cal. Utilities
Reports 8 to 34% savings in raw fuel when comparing On and Off Peak Operation!
• Heat Rates for Base Load Plants ~7,800 Btu/kWh vs. Peaking Plants ~9,400 to 14,000 Btu/kWh
The last power plants to come on during peak hours are normally the dirtiest per kW• Ashok Gupta (Director of Energy, NRDC) in NYTimes article “Peak
Shifting results in lower emissions because some of the plants used to meet demand peaks are among the dirtiest in the city”
• New CA Report by Greg Kats The Costs and Financial Benefits of Green Buildings states Peak power in CA is twice as dirty as Off Peak Power.
Thermal Energy Storage For Off-Peak Cooling
What is it?
How does it work?
Why is it Green?
Other “Green” Advantages
Other “Green” Issues
Safety Factors/Redundancy (Oversizing)
• Well documented that oversizing chiller plants creates less efficient real world operation.
• Engineers have to protect their license
Storage is the Natural solution
Safety Factor and Redundancy Without Oversizing for same Cost
0
200
400
600
800
1000
1200
1400
Time
Tons
Conventional System* 3-400 ton ChillersStorage System Excess CapacityDesign Day Load
Storage System2 - 400 ton Chiller
3,500 ton-hr Storage
* as per GSA Guideline P-100
Design Day Off-Peak Cooling System
0
200
400
600
800
1000
1200
1400
Time
Tons
Discharge StorageChillers Meeting LoadCharge Storage
Storage System2- 400 ton Chillers
3,500 ton-hr Storage
500 ton Load Reductionor ~ 375 kW
STORAGE DISCHARGE
CHILLERS(ONLY 500 TONS)
Installed Chillers Max Capacity
STORAGECHARGE
Costs of Storage
What’s the Installed Cost of a ton of Chiller Plant?
$1000/ton , $1200/ton, $1400/ton $1600/ton, $1800/ton
Storage Costs installed ~ $100 to $150 per ton-hr
Depending on location, application and design
For each 1 ton of chiller you reduce you need about 8 to 9 ton-hrs of storage.
Costs are similar to conventional design for New Construction
Thermal Energy Storage For Off-Peak Cooling
What is it?How does it work?Why is it Green?Other “Green” AdvantagesApplications/Case Studies
UL8,000 Ton-Hr2.5 days to install
Costco Installations 3 in Japan2 in Korea2 in USA
41 Stories3400 Ton Hours StorageAvoids 700kW out of 3500kW Original Total
Durst Headquarters Retrofit 1155 Avenue of the Americas
VFD PUMP
TS
TOLOAD
FROMLOAD
ICE STORAGE
ICE STORAGE
Ice Plant in Series with Water Chiller
HX
DEMAND LIMITEDTO 700 TONS
490 ICE-MAKING TONS
~1200 TONS
Credit Suisse 11 Madison Ave.
30 Stories, 2.2 Million Ft2
6200 Ton Hours Storage
Avoids ~ 900 kW
NYSERDA Incentive $620,000
Main reason for Storage: Resiliency
Morgan Stanley
Morgan StanleyWestchester, NY
1 Bryant Park Bank of America Tower2.2 Million Sqft
Bank of America Tower ICEBANK Facts
Over Half a Million Pounds of Ice made every night.
Enough Ice to Cool 250 Homes
1000 Tons of Air Conditioning Shifted to Off-Peak
Goldman-SachsNew York City
2.2 Million Sqft.6,000 tons Peak4,500 tons of Chiller (Only 3000 during the Day)
19,000 Ton-hr of Ice Storage~2 MW Reduction
Going for LEED Gold
Off-Peak Cooling… in over 6000 installations in 35 countries, many installed over 20 years ago
