Development of advanced materials guided by numerical simulations to improve performance and cost-efficiency of borehole heat exchangers (BHEs)

Badenes, Borja; Sanner, Burkhard; Cuevas, José M.; Bartoli, Flavia; Ciardelli, Francesco; González, Rosa; Ghafar, Ali Nejad; Fontana, Patrick; Zuñiga, Lenin Lemus; Urchueguı́a, Javier F.

doi:10.1016/j.energy.2020.117628

Cited by 37 publications

(37 citation statements)

References 9 publications

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“…There is currently a strong effort in developing new materials and drilling solutions to overcome this limitation and create more cost-competitive SGE approaches. This includes the engineering of new plastics, the integration of phase change materials in the grout and new drilling concepts [8,9].…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of the Shallow Geothermal Potential for Heating and Cooling and Its Integration in the Socioeconomic Environment: A Case Study in the Region of Murcia, Spain

2021

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In order to boost the use of shallow geothermal energy, reliable and sound information concerning its potential must be provided to the public and energy decision-makers, among others. To this end, we developed a GIS-based methodology that allowed us to estimate the resource, energy, economic and environmental potential of shallow geothermal energy at a regional scale. Our method focuses on closed-loop borehole heat exchanger systems, which are by far the systems that are most utilized for heating and cooling purposes, and whose energy demands are similar throughout the year in the study area applied. The resource was assessed based on the thermal properties from the surface to a depth of 100 m, considering the water saturation grade of the materials. Additionally, climate and building characteristics data were also used as the main input. The G.POT method was used for assessing the annual shallow geothermal resource and for the specific heat extraction (sHe) rate estimation for both heating and, for the first time, for cooling. The method was applied to the Region of Murcia (Spain) and thematic maps were created with the outputting results. They offer insight toward the thermal energy that can be extracted for both heating and cooling in (MWh/year) and (W/m); the technical potential, making a distinction over the climate zones in the region; the cost of the possible ground source heat pump (GSHP) installation, associated payback period and the cost of producing the shallow geothermal energy; and, finally, the GHG emissions savings derived from its usage. The model also output the specific heat extraction rates, which are compared to those from the VDI 4640, which prove to be slightly higher than the previous one.

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Section: Introductionmentioning

confidence: 99%

“…Defining a shallow geothermal system is directly dependent on end-user needs [8]. Conditions, in turn, depend on the climate, building typology, ground and working temperatures, among others, and are site-specific.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the Shallow Geothermal Potential for Heating and Cooling and Its Integration in the Socioeconomic Environment: A Case Study in the Region of Murcia, Spain

2021

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“…There have been many studies focusing on various methods to enhance the performance of BHEs [2,[15][16][17][18][19][20]. Pure water is reported to be the most commonly applied working fluid in the BHEs [2]; nevertheless, nanofluids' applications in the BHEs as working fluid has recently been under evaluation.…”

Section: Introductionmentioning

confidence: 99%

“…Figure15. Two-dimensional (2D) contours of the temperature distribution of the BHE at various hours of operating using Ag-MgO/water hybrid nanofluid at φ = 0.10 and Re = 3200 (Top view at Z = 0).…”

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Impact of Employing Hybrid Nanofluids as Heat Carrier Fluid on the Thermal Performance of a Borehole Heat Exchanger

et al. 2021

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In this numerical study, 4 types of hybrid nanofluid, including Ag-MgO/water, TiO2-Cu/water, Al2O3-CuO/water, and Fe3O4-multi-wall carbon nanotube/water, have been considered potential working fluid in a single U-tube borehole heat exchanger. The selected hybrid nanofluid is then analyzed by changing the volume fraction and the Reynolds number. Based on the numerical results, Ag-MgO/water hybrid nanofluid is chosen as the most favorable heat carrier fluid, among others, considering its superior effectiveness, minor pressure drop, and appropriate thermal resistance compared to the pure water. Moreover, it was indicated that all cases of Ag-MgO/water hybrid nanofluid at various volume fractions (from 0.05 to 0.20) and Reynolds numbers (from 3200 to 6200) could achieve better effectiveness and lower thermal resistances, but higher pressure drops compared to the corresponding cases of pure water. Nevertheless, all the evaluated hybrid nanofluids present lower coefficient of performance (COP)-improvement than unity which means that applying them as working fluid is not economically viable because of having higher pressure drop than the heat transfer enhancement.

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“…Research of new solutions capable of improving the heat exchange performances of SGS also regarding the probes, moved our point of view towards polyethylene materials doped with carbon fibre (CF) in order to produce hybridized geothermal probes [14,15]. Indeed, CF is a material characterized by exceptional mechanical properties and high thermal conductivity (~14 W/mK) [16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Innovative Solutions for Improving the Heat Exchange in Closed-Loop Shallow Geothermal Systems

et al. 2020

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Thermal conductivity, hydraulics properties and potential use in low-enthalpy geothermal applications of single and double U geothermal probes enhanced with carbon fibre are discussed in this work. Although the efficiency of a shallow geothermal installation is chiefly based on chemical and physical characteristics of rocks and hydrogeological aspects of the subsurface, the total heat extracted from the subsoil also depends on the intrinsic thermal characteristics of probes. New configurations and solutions aimed at enhancing the performance of components are therefore of considerable interest in this field of research. As a consequence of the economic and versatility advantages of the components, geothermal probes have been generally developed with materials like polyethylene, which presents, however, isolating behaviour that does not allow ideal heat exchange in ground source heat pump systems (GSHP). Innovative combinations of different materials are therefore necessary in order to improve thermal conductivity and to preserve the exceptional workability and commercial advantages of the finest elements available on the market. This work presents results coming from experimental tests involving standard polyethylene geothermal probes integrated with radial rings of polyacrylonitrile-based carbon fibre (PAN). Our evaluations are aimed at finding the best solutions for thermal exchange and adaptability with respect to traditional systems. Hydraulic and thermal performances and the response in a geo-exchange system have been verified. The new solutions appear to be highly suitable as geothermal exchangers in shallow geothermal systems and contribute to significantly reduce the total costs pertaining to the drilling operations.

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Development of advanced materials guided by numerical simulations to improve performance and cost-efficiency of borehole heat exchangers (BHEs)

Cited by 37 publications

References 9 publications

Evaluation of the Shallow Geothermal Potential for Heating and Cooling and Its Integration in the Socioeconomic Environment: A Case Study in the Region of Murcia, Spain

Evaluation of the Shallow Geothermal Potential for Heating and Cooling and Its Integration in the Socioeconomic Environment: A Case Study in the Region of Murcia, Spain

Impact of Employing Hybrid Nanofluids as Heat Carrier Fluid on the Thermal Performance of a Borehole Heat Exchanger

Innovative Solutions for Improving the Heat Exchange in Closed-Loop Shallow Geothermal Systems

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