Video inspection of wells in open loop ground source heat pump systems in Norway

Gjengedal, Sondre; Ramstad, Randi K.; Hilmo, Bernt Olav; Frengstad, Bjørrn

doi:10.22488/okstate.18.000025

Cited by 5 publications

(9 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The location of the pump high above the production well screen is a possible gas exsolution trigger. The current well design is not able to prevent gas bubbles from escaping the well bore [4]. If these gases are pH-regulating, e.g., CO 2 , the design might facilitate alterations of the groundwater chemistry and trigger precipitation reactions.…”

Section: Discussion and Comparison Of Design And Design Toolsmentioning

confidence: 99%

“…All of the seven re-injection systems have experienced clogging of the injection well screen [5]. The clogging material is often a mixture of sediments and precipitated hydroxides [3,4]. Inspections of the systems have shown that re-injection of groundwater is done without a backpressure technique, and vacuum pressures have been observed in the re-injection pipeline in several installations.…”

Section: Current Investigations In Melhusmentioning

confidence: 99%

“…Inspection of a particular production well in 2017 suggests that loss of pressure might be relevant for the observed fouling problems. The production wells in Melhus are seldom affected by clogging issues [4], but in this particular well, the pump was installed in the screened section of the well ( Figure 2b). During a routine maintenance check of the 15-m-long screen, a video-inspection of the well revealed a minor issue where precipitated iron hydroxides were found highly localized in the screen area at the location of the suction inlet section of the submersible pump, 10-11 m below the water table.…”

Section: Current Investigations In Melhusmentioning

confidence: 99%

“…The first installation started production in 1999 and is still in operation today. A range of clogging and fouling problems has occurred in the different systems over the years, leading to the recent investigations [2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Design of Groundwater Heat Pump Systems. Principles, Tools, and Strategies for Controlling Gas and Precipitation Problems

et al. 2019

Self Cite

View full text Add to dashboard Cite

The utilization of groundwater heat pump systems is increasing in Norway, which are currently widely employed for heating and cooling applications in the town center of Melhus. The investigations of the Melhus installations are detecting gas exsolution as a possible trigger for precipitation reaction that causes incrustation of iron and manganese compounds in the systems. This paper discusses risks associated with gas exsolution and considers gas exsolution triggers in a typical Norwegian groundwater heat pump (GWHP) system configuration. The concept of the solubility grade line (SGL) is developed and suggested as a tool for optimizing the design. Based on SGL analysis and the intention of avoiding gas exsolution during heat production, an alternative system design in the same aquifer is presented and compared. The analyses show that the traditional system design is predisposed to gas clogging risks and prone to vacuum pressures in parts of the system. The alternative design mediates the risks by adjusting the well and piping configuration and by applying a backpressure technique. The results demonstrate how the groundwater heat pump system design can be customized according to local aquifer conditions to avoid gas exsolution during operation. It is recommended that the presented method of analysis should be utilized in dimensioning of systems and included in the monitoring scheme of the systems.

show abstract

Section: Discussion and Comparison Of Design And Design Toolsmentioning

confidence: 99%

Section: Current Investigations In Melhusmentioning

confidence: 99%

Section: Current Investigations In Melhusmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Design of Groundwater Heat Pump Systems. Principles, Tools, and Strategies for Controlling Gas and Precipitation Problems

et al. 2019

Self Cite

View full text Add to dashboard Cite

show abstract

“…However, by identifying which of the four major components that are affected, the test results enable the operator to plan necessary maintenance to the affected components without having to spend time on unaffected parts of the system. The cause of the problem can then be identified through other means, such as by video inspection of the affected wells or pipes (Gjengedal et al 2018). Furthermore, the operator is able to investigate how effective the maintenance has been by conducting the same test procedure after the maintenance and comparing the results.…”

Section: Discussionmentioning

confidence: 99%

Fouling and clogging surveillance in open loop GSHP systems

Gjengedal

Ramstad

Hilmo

et al. 2019

Bull Eng Geol Environ

Self Cite

View full text Add to dashboard Cite

Fouling and clogging are some of the major water quality problems encountered in open loop ground source heat pump (GSHP) systems and aquifer thermal energy storage (ATES) systems. Here we present a surveillance strategy that can detect if and identify where in the system fouling and clogging might be developing without having to shut off the heat pump. In the presented system design, the test requires a minimum of four temperature sensors and two pressure sensors to describe the performance of the four major heat source system components, namely, the production well, the injection well, the submersible pump and the groundwater heat exchanger. The surveillance procedure involves conducting a step-test with incremental increases in the groundwater flow rate while measuring the pressure and temperature responses in the system components. The performance of the newly constructed installation functions as a baseline for future tests. By conducting the test systematically during operation an altered performance of the system can indicate clogging or fouling issues. Even though the cause of the problem must be identified through other means, the surveillance procedure presented here allows the operator to plan necessary maintenance and avoid critical damage to the heat source system.

show abstract

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

Gjengedal

Stenvik

Ramstad

et al. 2020

Bull Eng Geol Environ

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Video inspection of wells in open loop ground source heat pump systems in Norway

Cited by 5 publications

References 0 publications

Design of Groundwater Heat Pump Systems. Principles, Tools, and Strategies for Controlling Gas and Precipitation Problems

Design of Groundwater Heat Pump Systems. Principles, Tools, and Strategies for Controlling Gas and Precipitation Problems

Fouling and clogging surveillance in open loop GSHP systems

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

Contact Info

Product

Resources

About