University of Minnesota aquifer thermal energy storage (ATES) project report on the second long-term cycle

Technical Report · Sun Dec 01 04:00:00 EST 1991

DOI:https://doi.org/10.2172/5627755· OSTI ID:5627755

Hoyer, M C; Hallgren, J P; Lauer, J L; Walton, M; Eisenreich, S J; Howe, J T; Splettstoesser, J F ^[1]

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1. Minnesota Geological Survey, St. Paul, MN (United States)

The technical feasibility of high-temperature (>100{degrees}C (>212{degrees}F)) aquifer thermal energy storage (ATES) in a deep, confined aquifer was tested in a series of experimental cycles at the University of Minnesota's St. Paul field test facility (FTF). This report describes the second long-term cycle (LT2), which was conducted from October 1986 through April 1987. Heat recovery; operational experience; and thermal, chemical, hydrologic, and geologic effects are reported. Approximately 61% of the 9.21 GWh of energy added to the 9.38 {times} 10{sup 4} m{sup 3} of ground water stored during LT2 was recovered. Temperatures of the water stored and recovered averaged 118{degrees}C (244{degrees}F) and 85{degrees}C (185{degrees}F), respectively. Results agreed with previous cycles conducted at the FTF. System operation during LT2 was nearly as planned. Operational experience from previous cycles at the FTF was extremely helpful. Ion-exchange softening of the heated and stored aquifer water prevented scaling in the system heat exchangers and the storage well, and changed the major-ion chemistry of the stored water. Sodium bicarbonate replaced magnesium and calcium bicarbonate as primary ions in the softened water. Water recovered form storage was approximately at equilibrium with respect to dissolved ions. Silica, calcium, and magnesium were significantly higher in recovered water than in injected water. Sodium was significantly lower in water recovered than in water stored.

• Research Organization: Pacific Northwest Lab., Richland, WA (United States); Minnesota Geological Survey, St. Paul, MN (United States)
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC06-76RL01830
• OSTI ID: 5627755
• Report Number(s): PNL-7917; ON: DE92009561
• Country of Publication: United States
• Language: English

Related Subjects

25 ENERGY STORAGE
250600* -- Energy Storage-- Thermal
ALKALI METALS
AQUIFERS
CHEMISTRY
CONTROL
DEMONSTRATION PROGRAMS
ELEMENTS
ENERGY STORAGE
EQUIPMENT
FEASIBILITY STUDIES
GEOCHEMISTRY
GEOLOGY
GROUND WATER
HEAT EXCHANGERS
HEAT STORAGE
HYDROGEN COMPOUNDS
HYDROLOGY
MASS BALANCE
METALS
MINERALS
OXYGEN COMPOUNDS
QUALITY CONTROL
SCALING
SODIUM
STORAGE
THERMAL ENERGY STORAGE EQUIPMENT
WATER
WATER CHEMISTRY