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U.S. Department of Energy
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Aquifer thermal energy storage district cooling in downtown St. Paul: Feasibility study

Technical Report ·
OSTI ID:6957590

Is it feasible to store winter-chilled groundwater in an aquifer for summer air conditioning via a district cooling system. This study examined building loads, hydrogeologic factors, cooling system design, distribution alternatives, legal factors and economic feasibility. Groundwater would be pumped to the surface, cooled to 2.5/sup 0/C using ambient water air, and injected into a second well for storage. The original concept provided for chilling water in a district cooling loop by transferring ''chill'' from the stored water using a heat exchanger. The groundwater, after absorbing heat from the district cooling loop, would then be reinjected into the first well. A survey of chilling equipment in 36 buildings was conducted, and the costs of conversions to district cooling were estimated. A 200 foot deep, widely used sandstone/limestone aquifer was selected due to low cost per unit pumping capacity. Due to the constraints posed by economic competition with the status quo, the conceptual design was substantially modified: reject water from a large existing heat pump system was the presumed water source for winter cooling; and after summer retrieval and air conditioning use, water would be pumped to the storm sewer rather than reinjected.

Research Organization:
District Heating Development Co., St. Paul, MN (USA)
DOE Contract Number:
FG01-85CE26520
OSTI ID:
6957590
Report Number(s):
DOE/CE/26520-T1; ON: DE87003445
Country of Publication:
United States
Language:
English