Renewable District Cooling Using Oceans, Lakes and Aquifers Mark Spurr Bryan Kleist Börje Johansson IDEA Annual Conference Philadelphia, 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

Annual average Coefficient of Performance (COP)  Electric centrifugal chillers including auxilliaries 4-5  Deep water cooling Direct free cooling50-70 Including seasonal storage40-50

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

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)

Integration of deep water cooling and seasonal aquifer storage

Role of seasonal storage in Sollentuna annual cooling production

Sollentuna load duration curve

Operation of seasonal aquifer storage

Seasonal variations in sea and air temperatures

Järlasjö

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

Thanks for your attention! Questions? Mark Spurr Vice President FVB Energy Inc. 150 South 5th Street Minneapolis, MN Phone: 612/ Fax: 612/