Online remote-controlled and cost-effective fouling and clogging surveillance of a groundwater heat pump system

Abstract

Fouling and clogging of groundwater wells and heat exchangers are among the major operational challenges for groundwater heat pump (GWHP) and aquifer thermal energy storage (ATES) systems. This article presents the application of a step-test surveillance procedure developed for early detection of clogging in distinct parts of the GWHP system, tested at Lena Terrace in Melhus Norway. Three versions of the test procedure are presented and demonstrate that the test can be performed with a minimum of four steps, each of 15-min duration, while the GWHP system is actively producing heat. The results prove that the surveillance test can detect changes in the hydraulic resistance of the groundwater circuit and locate clogging problems within all of the relevant system components in the groundwater circuit simultaneously. At the Lena Terrace GWHP system, these tests indicate a gradual increase of hydraulic resistance with time, which verify that clogging issues are continuously developing in the injection well, in the production well, and in the groundwater heat exchanger. Cleaning of the heat exchanger was then performed. This increased the pumping capacity by 8.3% points, but continuous clogging of the injection well and the production well necessitates further maintenance to ensure a reliable operation. It is demonstrated that multidisciplinary competence and experience with GWHP-systems, aquifers, and groundwater wells are needed for the evaluation of the results. These results can therefore serve as a reference for other GWHP systems with similar design configurations.

Convective Acceleration in Porous Media

“…Particularly for the determination of the performance and the capacity of production wells and injection wells, i.e. in the petroleum industry (Huang and Ayoub 2008;Barree and Conway 2004), in groundwater wells utilized for domestic and irrigational purposes (Houben et al 2018;Wen et al 2011;van Lopik et al 2019), and for groundwater heat pump applications (Gjengedal et al 2021).…”

Forecasting hydraulic head changes in injection wells using LSTM network

“…An alternative surveillance method for open-loop GSHP is based on a step-drawdown test performed during normal system operation to determine potential fouling and clogging issues (Gjengedal et al, 2019). Although monitoring systems in GSHP applications can be easily implemented, accumulation of large data sets and a lack of hydrogeology expertise for data interpretation are some of the reported issues with these surveillance methods (Gjengedal et al, 2018(Gjengedal et al, , 2021. A new approach, based on residual analysis between predicted and measured water level in the well, has potential to detect gradual decreases in infiltration capacity.…”

Proceedings of the IGSHPA Research Track 2022

“…An alternative surveillance method for open-loop GSHP is based on a step-drawdown test performed during normal system operation to determine potential fouling and clogging issues . Although monitoring systems in GSHP applications can be easily implemented, accumulation of large data sets and a lack of hydrogeology expertise for data interpretation are some of the reported issues with these surveillance methods (Gjengedal et al, 2018(Gjengedal et al, , 2021. A new approach, based on residual analysis between predicted and measured water level in the well, has potential to detect gradual decreases in infiltration capacity.…”