How a sensitive analysis on the coupling geology and borehole heat exchanger characteristics can improve the efficiency and production of shallow geothermal plants

Chicco, Jessica; Mandrone, Giuseppe

doi:10.1016/j.heliyon.2022.e09545

Cited by 10 publications

(5 citation statements)

References 30 publications

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“…Precisely, measurements were performed during the ageing of the grout used to seal the space between the wall boreholes and the geothermal pipe inside the BHE. As widely proved in [27], grout is another important element involved in the heat transfer process; therefore, verifying the ground temperatures in a BHE also entails testing the grout stability during its ageing. For this purpose, a specific device was installed to measure the temperature continuously (1000 Series Squirrel, Eltek Ltd., Cambridge, UK) over a period of 16 days.…”

Section: Monitoring Of Ground Temperature and Grout Ageingmentioning

confidence: 99%

“…According to what was specified in [23,27], this software enables analyses of each part of the ground/aquifer/pipe system, as well as to obtain the amount of thermal power that can be extracted from the investigated medium using specific boundary conditions. These features allow a high level of numerical efficiency to be provided and, thus, an accurate sensitivity analysis.…”

Section: Numerical Simulation Of the Field Grtmentioning

confidence: 99%

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Hybrid (Gas and Geothermal) Greenhouse Simulations Aimed at Optimizing Investment and Operative Costs: A Case Study in NW Italy

et al. 2023

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Generally, greenhouses are high energy-consuming, sometimes accounting for 50% of the cost of greenhouse production. Geothermal energy plays a very important role in maintaining the desired temperature and reducing energy consumption. This work deals with a project of a hybrid heating plant (97% geothermal energy and 3% gas-condensing boiler) for the innovative Plant Phenotyping Greenhouse at the University Campus in Grugliasco (few km West of the city of Turin). The aim of the study is to testify to the energy efficiency of this kind of hybrid plant as well as its economic sustainability. Numerical simulations of a GRT were used to calibrate the system and verify that the software reasonably modeled the real case. They helped to correctly size the geothermal plant, also providing data about the thermal energy storage and production during on and off plant cycles. The results show a thermal power of 50.92 kW over 120 days of plant operation, in line with the expected energy needs to meet the base load demand. Long-term results further ensure a negligeable impact on the ground, with a thermal plume between 5 and 10 m from the plant, reducing substantially in a few months after switching off the plant.

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Section: Monitoring Of Ground Temperature and Grout Ageingmentioning

confidence: 99%

Section: Numerical Simulation Of the Field Grtmentioning

confidence: 99%

Hybrid (Gas and Geothermal) Greenhouse Simulations Aimed at Optimizing Investment and Operative Costs: A Case Study in NW Italy

et al. 2023

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“…A global refinement of the entire mesh has been set up with a 0.2 m for polygons and point target size, as well as a point gradation of 2. As specified in previous works (Chicco and Mandrone, 2022a;Chicco and Mandrone, 2022b) a further mesh smoothing has been done, to avoid irregular shaped elements and obtuse-angled triangles. A further check for obtuse angles and triangles violating the Delaunay criterion, has also been conducted.…”

Section: Numerical Modellingmentioning

confidence: 99%

Effects of wildfire on soils: field studies and modelling on induced underground temperature variations

Chicco,

Mandrone,

Vacha

2023

Front. Earth Sci.

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Wildfire statistics report an increasing number of deaths, damages, and force society to face exceptional repair costs also due to secondary effects such as landslides, soils erosion and water quality problems. Literature agrees that the extent of the thermal disturbance of the soil due to wildfire is strongly dependent on fire intensity, on its duration and recurrence, as well as on fuel load, and soil properties. The unpredictability of these phenomena is one of the main challenges for scientists trying to study their characteristics. Degradation of the biological, chemical, and physical properties of forest soils due to the wildfires can reduce their capacity to function fully, with such effects either temporary or permanent. Direct measurements of the effects of these phenomena are difficult to be collected in the field, especially when the area affected by fires is a wilderness. In this study, controlled fires reproducing real conditions of wildfire affecting the Susa Valley (NW Italy) in 2017, which induced intense erosion and debris flows, have been monitored both above and below the ground surface. Moreover, numerical simulations based on real data increased the know-how to reproduce real changes on the underground. The small-scale fire simulations have allowed to verify how the depth affected by significant increases in temperatures is truly pellicular. Field tests show that at −2 cm depth temperature never exceed 70°C, meaning that it usually does not affect soil components or properties. The results of the study suggest that temperature variations in the subsoil are very localized and limited. If confirmed by further studies, the processes inferred to produce large ground effects on slopes after wildfires should be re-considered.

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“…In this study, the temperature measurements showed increasing rates of 0.135 • C/year at a depth of 10 m and 0.118 • C/year at a depth of 50 m. Discharging heat in the cooling season and extracting heat in the heating season resulted in a 0.109 • C/year increase in temperature over 10 years. Authors in another study found a higher extraction rate can be obtained in porous lithologies than clay or silt when applying a grout with high thermal conductivity [26]. Others have analysed the seasonal regeneration of ground-source heat pumps by re-injection of space cooling to the ground [27].…”

Section: Introductionmentioning

confidence: 99%

Assessing the Impact of a Shallow Geothermal System Operation through Multi-Layer Temperature Monitoring in a Mediterranean Climate

Aljundi,

Vieira,

Lapa

et al. 2024

Geosciences

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Shallow Geothermal Energy (SGE) exchanges heat with the ground. In continuous, long-term operation, the initial temperature field can be disturbed, and subsurface thermal changes can be developed. In this paper, the thermal impact of a SGE system under a Mediterranean climate is handled. Temperature monitoring was conducted on 15 investigation boreholes equipped with a total of 92 thermal sensors placed at specific depths. Investigation boreholes were drilled 1–2 m from SGE system borehole heat exchangers installed in a university building. The analysis handles a one-year monitoring period of SGE system operation. Temperature depth profiles, reaching up to 140 m depth, were registered with a 10 min time step, resulting in a large amount of data. Ground thermal conductivity was estimated experimentally and semi-empirically, allowing us to obtain, using a numerical model, the initial undisturbed ground temperature profiles and compare them with the monitored values. Climate data were recorded by the university meteorological station. Globally, the measured and computed data were coherent, and a non-negligible impact of the SGE system operation in the first year was observed. The building orientation as well as the nearby departments had significant impacts on the shallow ground temperature. Maximum ground temperature changes observed at depths higher than 10–20 m, ranging from 2 to 3 °C as observed in different boreholes, indicate that the system is operating efficiently.

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How a sensitive analysis on the coupling geology and borehole heat exchanger characteristics can improve the efficiency and production of shallow geothermal plants

Cited by 10 publications

References 30 publications

Hybrid (Gas and Geothermal) Greenhouse Simulations Aimed at Optimizing Investment and Operative Costs: A Case Study in NW Italy

Hybrid (Gas and Geothermal) Greenhouse Simulations Aimed at Optimizing Investment and Operative Costs: A Case Study in NW Italy

Effects of wildfire on soils: field studies and modelling on induced underground temperature variations

Assessing the Impact of a Shallow Geothermal System Operation through Multi-Layer Temperature Monitoring in a Mediterranean Climate

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