Solute and heat transport in groundwater similarity: Model application of a high capacity open-loop heat pump

Beretta, Giovanni Pietro; Coppola, Gabriele; Pona, Lucio Della

doi:10.1016/j.geothermics.2013.10.009

Cited by 16 publications

(5 citation statements)

References 11 publications

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“…The plume length has a roughly logarithmic correlation with the flow rate, and an increase in by a factor of ten results in a fourfold increase in the plume length. On the other hand, the width of the thermally affected area increases almost linearly with the injected flow rate (Figure 9c), as expected from Equation (14). The thermal alteration induced downstream of the injection well during each heating season interacts with the plume generated during the previous cooling season, determining the temperature The injected-water flow rate and, therefore, the thermal power exchanged with the ground, has a very strong influence on thermal plume propagation (Figure 9d).…”

Section: Sensitivity Analysissupporting

confidence: 77%

“…GWHPs exchange heat with groundwater extracted through one or multiple water wells, and are increasingly employed as an air conditioning system, especially for large commercial and public buildings [13][14][15][16]. Groundwater is usually reinjected through wells into the same aquifer to avoid its depletion [17], but this leads to the formation of thermally altered zones, called thermal plumes.…”

Section: Introductionmentioning

confidence: 99%

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Thermal Impact Assessment of Groundwater Heat Pumps (GWHPs): Rigorous vs. Simplified Models

et al. 2017

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Groundwater Heat Pumps (GWHPs) are increasingly adopted for air conditioning in urban areas, thus reducing CO 2 emissions, and this growth needs to be managed to ensure the sustainability of the thermal alteration of aquifers. However, few studies have addressed the propagation of thermal plumes from open-loop geothermal systems from a long-term perspective. We provide a comprehensive sensitivity analysis, performed with numerical finite-element simulations, to assess how the size of the thermally affected zone is driven by hydrodynamic and thermal subsurface properties, the vadose zone and aquifer thickness, and plant setup. In particular, we focus the analysis on the length and width of thermal plumes, and on their time evolution. Numerical simulations are compared with two simplified methods, namely (i) replacing the time-varying thermal load with its yearly average and (ii) analytical formulae for advective heat transport in the aquifer. The former proves acceptable for the assessment of plume length, while the latter can be used to estimate the width of the thermally affected zone. The results highlight the strong influence of groundwater velocity on the plume size and, especially for its long-term evolution, of ground thermal properties and of subsurface geometrical parameters.

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Section: Sensitivity Analysissupporting

confidence: 77%

Section: Introductionmentioning

confidence: 99%

Thermal Impact Assessment of Groundwater Heat Pumps (GWHPs): Rigorous vs. Simplified Models

et al. 2017

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“…Ref. [50] considered the similarity between solutes and heat transport within aquifers. They simulated scenarios for heatpump operation in the Canavese power station, which has a maximum water withdrawal rate of 0.3 m 3 /s.…”

Section: Gwhp Systems: Technological Potential and Environmental Limitsmentioning

confidence: 99%

A Review of Groundwater Heat Pump Systems in the Italian Framework: Technological Potential and Environmental Limits

et al. 2023

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For new buildings in densely urbanised cities, groundwater heat pump systems (GWHPs) represent a concrete, effective solution for decarbonising existing energy systems. Environmental factors must be considered to limit the GWHP system’s impact on the subsurface. Particular attention must be given to the long-term sustainability of groundwater abstraction modalities and the development of a thermally affected zone around re-injection wells. Simplified solutions and numerical models have been applied to predict subsurface heat transport mechanisms; these simulations allow researchers to consider site-specific geological conditions, transient heat and groundwater flow regimes, and anisotropies in the subsurface media. This paper presents a comprehensive overview of the current research on GWHPs and discusses the benefits and limitations of their diffusion in Italy. The sources used provide information on and examples of the correct methodological approaches for depicting the induced variations while avoiding the overestimation or underestimation of the impact that GWHPs have on exploited aquifers.

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“…For example, assuming the seasonal average value of the COP (SCOP) equal to 5.79 (see Appendix B.1), the heating power would be 38.36 MW; on the other hand, the cooling power with Seasonal EER (SEER) equal to 5.84 (see Appendix B.1) would be 27.12 MW. As a term of comparison, this value slightly exceeds the sum of the two largest groundwater heat pumps in Italy (15 MW each), which have been installed in two district heating power stations in Milano [45]. The energy potentially delivered by these systems was estimated by calculating the full-load equivalent hours (FLEH) in heating and cooling mode using the method proposed by Papakostas et al (2009, [46]).…”

Section: Potential Application To the Italian Contaminated Sites Of Nmentioning

confidence: 99%

How Can We Make Pump and Treat Systems More Energetically Sustainable?

Casasso

Tosco

Bianco

et al. 2019

Water

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Pump and treat (P&T) systems are still widely employed for the hydraulic containment of contaminated groundwater despite the fact that their usage is decreasing due to their high operational costs. A way to partially mitigate such costs, both in monetary and environmental terms, is to perform heat exchange (directly or with a heat pump) on the groundwater extracted by these systems, thus providing low-carbon and low-cost heating and/or cooling to buildings or industrial processes. This opportunity should be carefully evaluated in view of preserving (or even improving) the removal efficiency of the remediation process. Therefore, the heat exchange should be placed upstream or downstream of all treatments, or in an intermediate position, depending on the effect of water temperature change on the removal efficiency of each treatment step. This article provides an overview of such effects and is meant to serve as a starting reference for a case-by-case evaluation. Finally, the potentiality of geothermal use of P&T systems is assessed in the Italian contaminated Sites of National Interest (SIN), i.e., the 41 priority contaminated sites in Italy. At least 29 of these sites use pumping wells as hydraulic barriers or P&T systems. The total discharge rate treated by these plants exceeds 7000 m3/h and can potentially provide about 33 MW of heating and/or cooling power.

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Solute and heat transport in groundwater similarity: Model application of a high capacity open-loop heat pump

Cited by 16 publications

References 11 publications

Thermal Impact Assessment of Groundwater Heat Pumps (GWHPs): Rigorous vs. Simplified Models

Thermal Impact Assessment of Groundwater Heat Pumps (GWHPs): Rigorous vs. Simplified Models

A Review of Groundwater Heat Pump Systems in the Italian Framework: Technological Potential and Environmental Limits

How Can We Make Pump and Treat Systems More Energetically Sustainable?

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