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University of Minnesota Aquifer Thermal Energy Storage (ATES) project report on the first long-term cycle

Description: The technical feasibility of high-temperature (>100{degrees}C) aquifer thermal energy storage (IOTAS) 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 additions to the FTF for the long-term cycles and the details of the first long-term cycle (LT1) that was conducted from November 1984 through May 1985. Heat recovery; operational experience; and thermal, chemical, hydrologic, and geologic aspects of LT1 are reported. The permits for long-term cycles required the addition of a monitoring well 30.5 m from the storage well for monitoring near the edge of the thermally affected area and allowed the addition of a cation-exchange water softener to enable continuous operation during the injection phase. Approximately 62% of the 9.47 GWh of energy added to the 9.21 {times} 10{sup 4} m{sup 3} of ground water stored in the aquifer LT1 was recovered. Ion-exchange water softening of the heated and stored ground water prevented scaling in the system heat exchangers and the storage well and changed the major-ion chemistry of the stored water. Temperatures at the storage horizons in site monitoring wells reached as high as 108{degrees}C during the injection phase of LT1. Following heat recovery, temperatures were <30{degrees}C at the same locations. Less permeable horizons underwent slow temperature changes. No thermal or chemical effects were observed at the remote monitoring site. 25 refs.
Date: October 1, 1991
Creator: Walton, M. (Minnesota Geological Survey, St. Paul, MN (United States))
Partner: UNT Libraries Government Documents Department

Design of a Groundwater Sampling Network for Minnesota

Description: From introduction: This folio was compiled to facilitate the use of groundwater as a sampling medium to aid in exploration for hitherto undiscovered deposits of uranium in the subsurface rocks of Minnesota. The report consists of the following sheets of the hydrogeologic map of Minnesota: 1) map of bedrock hydrogeology, 2) generalized cross sections of the hydrogeologic map of Minnesota, showing both Quaternary deposits and bedrock, 3) map of waterwells that penetrate Precambrian rocks in Minnesota. A list of these wells, showing locations, names of owners, type of Precambrian aquifers penetrated, lithologic material of the aquifers, and well depths is provided in the appendix to this report.
Date: January 1978
Creator: Kanivetsky, Roman
Partner: UNT Libraries Government Documents Department

Quaternary Geology of Minnesota and Parts of Adjacent States

Description: Description of geology in Minnesota and explanations of glacial drift within the state an immediate surroundings (Wisconsin, Iowa, North Dakota and South Dakota) with sections detailing the movement of each glacier and relevant geological notes. Index starts on page 147.
Date: 1930
Creator: Leverett, Frank, 1859-1943
Location Info:
Partner: UNT Libraries Government Documents Department

Preliminary Evaluation of the Ground-Water-Flow System in the Twin Cities Metropolitan Area, Minnesota

Description: From abstract: A preliminary quasi-three-dimensional finite-difference ground-water-flow model of the seven-county Twin Cities Metropolitan area was constructed and used to evaluate parameter sensitivity and adequacy of available data.
Date: August 1982
Creator: Guswa, J. H.; Siegel, D. I. & Gillies, D. C.
Partner: UNT Libraries Government Documents Department

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

Description: 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.
Date: December 1, 1991
Creator: Hoyer, M.C.; Hallgren, J.P.; Lauer, J.L.; Walton, M.; Eisenreich, S.J.; Howe, J.T. et al.
Partner: UNT Libraries Government Documents Department

The University of Minnesota aquifer thermal energy storage (ATES) field test facility -- system description, aquifer characterization, and results of short-term test cycles

Description: Phase 1 of the Aquifer Thermal Energy Storage (ATES) Project at the University of Minnesota was to test the feasibility, and model, the ATES concept at temperatures above 100{degrees}C using a confined aquifer for the storage and recovery of hot water. Phase 1 included design, construction, and operation of a 5-MW thermal input/output field test facility (FTF) for four short-term ATES cycles (8 days each of heat injection, storage, and heat recover). Phase 1 was conducted from May 1980 to December 1983. This report describes the FTF, the Franconia-Ironton-Galesville (FIG) aquifer used for the test, and the four short-term ATES cycles. Heat recovery; operational experience; and thermal, chemical, hydrologic, and geologic effects are all included. The FTF consists of monitoring wells and the source and storage well doublet completed in the FIG aquifer with heat exchangers and a fixed-bed precipitator between the wells of the doublet. The FIG aquifer is highly layered and a really anisotropic. The upper Franconia and Ironton-Galesville parts of the aquifer, those parts screened, have hydraulic conductivities of {approximately}0.6 and {approximately}1.0 m/d, respectively. Primary ions in the ambient ground water are calcium and magnesium bicarbonate. Ambient temperature FIG ground water is saturated with respect to calcium/magnesium bicarbonate. Heating the ground water caused most of the dissolved calcium to precipitate out as calcium carbonate in the heat exchanger and precipitator. Silica, calcium, and magnesium were significantly higher in recovered water than in injected water, suggesting dissolution of some constituents of the aquifer during the cycles. Further work on the ground water chemistry is required to understand water-rock interactions.
Date: June 1, 1991
Creator: Walton, M.; Hoyer, M.C.; Eisenreich, S.J.; Holm, N.L.; Holm, T.R.; Kanivetsky, R. et al.
Partner: UNT Libraries Government Documents Department