Gas-phase formation during thermal energy storage in near-surface aquifers: experimental and modelling results

Time-lapse electrical resistivity imaging of the thermally affected zone of a Borehole Thermal Energy Storage system near Torino (Northern Italy)

“…imaging of heated water injection (Benderitter and Tabbagh, 1982;Hermans et al, 2015), monitoring of gas-phase formation due to heat storage (Lüders et al, 2016), geothermal exploration (Bruno et al, 2000;Garg et al, 2007), monitoring the performance of low enthalpy ground source energy systems (Fragkogiannis et al, 2008;Firmbach et al, 2013) and localizing the burning front of underground coal fires (Revil et al, 2013) to name but a few. Nevertheless, more examples are particularly necessary in real scale applications, since calibrated, robust and reliable correlations between electric resistivity and temperature are not available yet (Robert et al, 2013).…”

Effects of thermal energy storage on shallow aerobic aquifer systems: temporary increase in abundance and activity of sulfate-reducing and sulfur-oxidizing bacteria

“…Afterwards, three of the columns were heated up to 25 °C, 40 °C and 70 °C by wrapping them with heating tapes and 1.9 cm thick insulating material (AF-19MM/E; Armacell), while one column remained at 10 °C in the fridge as a reference. A more detailed description of the experimental setup is given in Lueders et al (2016). In the following, the start of heating is termed as day 0, thus all data of days numbered with a "minus" were in the equilibrium phase at 10 °C.…”

“…In accordance, the bands affiliated to bacteria taking part in pyrite oxidation such as Sideroxydans weakened. Lueders et al (2016) showed a stronger gas phase formation in the 40 °C and °C heated columns due to a lower solubility at higher temperatures. This likely led to a reduced retention time of the fluids in the columns, to local zones without oxygen and thus to less pyrite oxidation and better conditions for anaerobic bacteria such as SRB.…”

Predictability of initial hydrogeochemical effects induced by short-term infiltration of ∼75 °C hot water into a shallow glaciogenic aquifer

“…This includes processes associated with operational issues, such as i) accelerated corrosion ( Andersson, 1990 ; Jenne et al., 1992 ); ii) the precipitation of carbonates ( Griffioen and Appelo, 1993 ) and Fe and Mn (hydr)oxides ( Andersson, 1990 ; Willemsen, 1990 ) that can cause scaling within heat exchangers, pipes and in and around wells; iii) the formation of a separate gas phase ( Lüders et al., 2016 ) that can block pipes or parts of the near-well pore space and iv) the dissolution of amorphous silica and silicates at increased temperatures ( Arning et al., 2006 ; M. Bonte et al., 2013b ; Holm et al., 1987 ) that can precipitate when the water is cooled in the surface installations during heat recovery ( Gunnarsson and Arnórsson, 2005 ). There are also processes associated with potential changes in groundwater quality, such as i) the release of dissolved organic carbon (DOC) and associated redox processes ( Bonte et al., 2013a ; Brons et al., 1991 ; Jesußek et al., 2013a ; 2013b ); ii) the release and fixation of trace elements and heavy metals ( M. Bonte et al., 2013b ; García-Gil et al., 2016 ; Lüders et al., 2020 ; Saito et al., 2016 ) and iii) increased or decreased solubility ( Koproch et al., 2019 ), volatilisation ( Schwardt et al., 2021 ) and degradation ( Men and Cheng, 2011 ; Němeček et al., 2018 ; Zuurbier et al., 2013 ) of organic contaminants.…”

“…These hydrogeochemical processes have been investigated in laboratory studies using batch ( Arning et al., 2006 ; Jesußek et al., 2013a ; Koproch et al., 2019 ; Men and Cheng, 2011 ; Schwardt et al., 2021 ), flow-through ( Bonte et al., 2013a ; M. 2013b ; Griffioen and Appelo, 1993 ; Jesußek et al., 2013a ; 2013b ; Lüders et al., 2016 ) and circular flow column tests ( Lüders et al., 2020 ). Furthermore, attempts have been made to empirically categorise trace elements and heavy metals relevant for administrative approval ( Lüders et al., 2020 ).…”