Impact of Standing Column Well Operation on Carbonate Scaling

Standing column wells are a promising solution to reduce the environmental footprint of building energy consumption. Nevertheless, as in other open-loop wells, they can be affected by clogging processes if detrimental hydrogeological conditions are present locally. This problem is relatively rare and still difficult to anticipate, even though some specific factors have been reported, such as substratum mineralogy and groundwater quality. This study proposes the use of a column experiments and coupon cell to anticipate clogging at two different sites near Montréal, Canada. The experiments were performed for duration of 50 and 52 d using thermoregulated columns at four temperatures. The results identified a difference in the chemistry of each site without any significant clogging risk. Site A showed a decrease in carbonates, magnesium, and calcium ions, and scanning electron microscopy showed a minor tendency to form carbonate deposits. Sulfate and calcium dissolution of the bedrock material were observed at Site B. Scanning electron microscopy of the coupons revealed organic matter with high carbon and sulfate concentrations. The same type of deposits was observed at Site B after three years of operation. In conclusion, these tests helped identify various potential clogging phenomena and indicated that both sites are not susceptible to major clogging risks.

Section: Column Bmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Column experiments to anticipate clogging of standing column wells

Cerclet¹,

Courcelles²,

Pasquier³

2022

“…4). See Beaudry et al (2019), Nguyen et al (2020), andCerclet et al (2020) for further details about this installation. Multi-flow rate thermal response test.…”

Section: Data Acquisitionmentioning

confidence: 99%

Dynamic simulation of ground source heat pump systems with nonstationary convolutions

Beaudry¹,

Pasquier²

2022

Advective processes related to groundwater motion and flow rates have a significant impact on the thermal performance of ground source heat pump systems. Including these elements during the design phase, however, remains a challenging task, as few computationally efficient modeling tools allow for their adequate and accurate representation. The present work addresses this issue by presenting the experimental validation of non-stationary convolutions for predicting the thermal response of a ground heat exchanger to both transient heat loads and advection. First, the method is outlined along with a simple demonstration case emulating the time-variation of groundwater velocity. Then, it is validated against experimental data retrieved from a 35-day multi-flow rate thermal response test conducted on a real standing column well. The results show a mean absolute error of 0.28 °C between the experimental and simulated results, which represents good accuracy considering the complexity of the thermo-hydro-processes at work. The high computing efficiency of the proposed technique is also demonstrated and suggests its potential for future implementation in common-use design tools.

“…• The geological environment was not favorable: the hydraulic conductivity of the aquifer (K = 5.7 10 -7 m/s) in Varennes is low as well as the thermal conductivity (k = 2.74 W m -1 K -1 ) (Beaudry et al, 2019). Furthermore, the groundwater composition promoted carbonate scaling (Cerclet et al, 2020).…”

Section: Standing Column Wells In Cold Climatesmentioning

confidence: 99%

Control strategy evaluation framework for ground source heat pumps using standing column wells

Tonellato¹,

Kummert²,

Candanedo³

et al. 2022

Standing column wells (SCWs) are efficient ground heat exchangers (GHEs) that have a significant cost saving potential. Recent developments have shown that they can also adapt successfully to cold climates despite previous concerns about operating near the freezing point. Therefore, new research frontiers are now being explored as the integration of this type of GHE to a real case study building model has hardly been analyzed until now. An institutional building has been selected for a SCW demonstration project in Mirabel, Canada. This paper includes in one single model the building, the Heating Ventilation and Air Conditioning (HVAC) system and the SCWs. The objective is to develop a software framework to analyze the impact of building operation strategies on the entire system during winter. Peak loads revealed to be the most critical points to control as the groundwater can freeze if the heat extraction is too high. Night indoor air temperature setbacks can bring significantly high peak loads whenever the building is heated to be occupied during the day. This paper shows that, using a bleed ratio above 20 %, a night setback can be successfully operated ramping up the temperature in around 3 hours.