Renewable District Cooling Using Oceans, Lakes and

Aquifers

Mark Spurr

Bryan Kleist

Börje Johansson

IDEA Annual ConferencePhiladelphia, PA

June 2003

Abstract Deep water cooling using lakes and seas as a heat sink, sometimes

in conjunction with heat pumps, has been used successfully in Scandinavia for over 15 years. FVB has served as consultant on design and development of 7 deep water cooling district cooling systems now in commercial operation. This paper highlights several of these systems, including:• Stockholm, Sweden. The Baltic Sea is used in combination

with heat pumps to supply over 70,000 tons of cooling for downtown Stockholm.

• Södertälje, Sweden. 17,000 ton district cooling system at Lake Mälaren supplying a pharmaceutical plant and other commercial customers.

• Sollentuna, Sweden. 1,100 ton district cooling system that includes aquifer storage. During the winter, cold sea water from a bay of the Baltic Sea is stored in the aquifer to reduce temper the warmer sea water during summer.

Commercial deep water cooling systems• Under development

– Toronto – fresh water lake– Hawaii – sea water

• Operating– Cornell University – fresh water lake– Halifax – sea water– Stockholm, Sweden – sea water plus heat pump– Södertälje, Sweden – fresh water lake– Sollentuna -- sea water plus seasonal aquifer storage– Uppsala Väsby – deep water plus heat pump– Järlasjö lake – fresh water lake– Nacka Strand – sea water– Norrenergi – sea water

Deep water cooling

Courtesy Cornell University www.utilities.cornell.edu/LSC

Annual average Coefficient of Performance (COP)

Electric centrifugal chillers including auxilliaries 4-5

Deep water cooling • Direct free cooling 50-70• Including seasonal storage 40-50

Stockholm, Sweden

Södertälje, Sweden

• Telgi Energi uses cold water from Lake Mälaren provides cooling to a large pharmaceutical plant and other commercial customers

• Production capacity 17,000 tons• Supply temperature less than 48F all year long• Source depth 148 ft• Supply flow rate 26,400 gpm• District cooling distribution 3.7 miles of 39 inch

diameter polyethylene pipe

Södertälje

Lake Mälaren water temp.

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Temp 40m

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Pipe installation in Lake Mälaren

Pump station installed in shallow water

Sollentuna, Sweden

Operated by Sollentuna Energi Production capacity 1,100 tons Aquifer storage capacity 730,000 ton-hrs

• Supply temperature 45F• Source depth 50 feet

Pipe materials• Polyethylene for pipe installed in the bay• Stainless steel for customer connections• Carbon steel for underground pipe

Temperatures stable at 15 m (50 ft)

Temperature in Edsviken (bay of Baltic sea)

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grC 15 m

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Integration of deep water cooling and seasonal aquifer storage

Role of seasonal storage in Sollentuna annual cooling production

Jan Feb Mars April Maj Juni Juli Aug Sept Okt Nov Dec Jan Feb Mars April May June July Aug Sept Oct Nov Dec

Cooling demand DC

Free cooling from Edsviken

Cooling from Storage

Sollentuna load duration curve

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Free cooling

Operation of seasonal aquifer storage

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99-07-03 99-08-02 99-09-01 99-10-02 99-11-01 99-12-02 00-01-01 00-02-01 00-03-02 00-04-01 00-05-02 00-06-01 00-07-02 00-08-01

Ground water temp.Observation well #1

Ground water temp.Observation well #2

Ground water temp.Observation well #3

[°C] Alteration of m ean tem peratures in observation wells during charge/discharge-cyc le 1999-2000

Discharge period

Charge period

Rest period

Seasonal variations in sea and air temperatures

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Sea temp. @ 15 m depth

Sea temp. @ 5 m depth

Outdoor temperure

Poly. (Outdoor temperure)

Seawater and air tem peratures in Sollentuna 1999 - 2000

JärlasjöTemperature in lake Järlasjön

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Södertälje Environmental Report Environmental impact report

• Prepared by Anders Broberg, Ph.D., Swedish Institute of Limnology

• Translated from Swedish by Gordon Bloomquist Major issues

• Laying of pipeline (approximately 6 km or 3.5 miles)– Turbidity– Mercury

• Intake of water• Discharge of water at elevated temperature• Heating of water surrounding pipe line• Nutrients

Cooling outfall

Courtesy Cornell University www.utilities.edu/LSC

Thanks for your attention!

Questions?

Mark SpurrVice PresidentFVB Energy Inc.150 South 5th Street Minneapolis, MN 55402Phone: 612/607-4544Fax: 612/338-3427mspurr@fvbenergy.com www.fvbenergy.com