Browsing by Author "Verdin, Patrick"

Now showing 1 - 9 of 9
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    Conjugated numerical approach for modelling DBHE in high geothermal gradient environments
    (MDPI, 2020-11-21) Renaud, Théo; Verdin, Patrick; Falcone, Gioia
    Geothermal is a renewable energy source that can be untapped through various subsurface technologies. Closed geothermal well solutions, such as deep geothermal heat exchangers (DBHEs), consist of circulating a working fluid to recover the available heat, with less dependency on the local geological settings than conventional geothermal systems. This paper emphasizes a double numerical method to strengthen the assessment of DBHE performances. A computational fluid dynamics (CFD) commercial software and the 1D coupled wellbore-reservoir geothermal simulator T2Well have been used to investigate the heat transfer and fluid flow in a vertical DBHE in high geothermal gradient environments. The use of constant water properties to investigate the energy produced from DBHEs can lead to underestimating the overall heat transfer at high temperature and low mass flow rate. 2D axisymmetric CFD modelling improves the understanding of the return flow at the bottom of the DBHE, readjusting and better estimating the pressures losses commonly obtained with 1D modelling. This paper highlights the existence of convective cells located at the bottom of the DBHE internal tubing, with no significant effects due to the increase of injected water flow. Both codes are shown to constrain the numerical limitations to access the true potential of geothermal heat extraction from DBHEs in high geothermal gradient environments and demonstrate that they can be used for geothermal energy engineering applications.
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    Data for "Numerical simulation of a Deep Borehole Heat Exchanger in the Krafla geothermal system"
    (Cranfield University, 2019-08-23 13:56) Renaud, Théo; Verdin, Patrick
    Data related to the paper: "Numerical simulation of a Deep Borehole Heat Exchanger in the Krafla geothermal system"
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    Dataset for "Analytical and Numerical Predictions of the Thermal Performance of Multi-Layered Lattice Structures"
    (Cranfield University, 2019-10-04 12:17) Verdin, Patrick; Ernot, Jean; Ahmad, Ayder; Indge, Philip
    Numerical data corresponding to the paper entitled: "Analytical and Numerical Predictions of the Thermal Performance of Multi-Layered Lattice Structures"
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    Dataset for "Conjugated Numerical Approach for Modelling DBHE in High Geothermal Gradient Environments"
    (Cranfield University, 2020-12-07 09:10) Verdin, Patrick; Renaud, Théo; Falcone, Gioia
    Numerical data corresponding to the journal paper entitled: "Conjugated Numerical Approach for Modelling DBHE in High Geothermal Gradient Environments"
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    Dataset for "Numerical Analysis of Enhanced Conductive Deep Borehole Heat Exchangers",Cranfield University,CC BY 4.0,https://creativecommons.org/licenses/by/4.0/ Wadi et al. Pap1 CORD-Updated.xlsx,Wadi
    (Basil, 2021-06-14 09:00) Verdin, Patrick; Renaud, Théo; Falcone, Gioia; Doran, Hannah; Pan, Lehua
    Numerical data corresponding to the journal paper entitled: "Numerical Analysis of Enhanced Conductive Deep Borehole Heat Exchangers"
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    Floating solar wireless power transfer system for electric ships: design and laboratory tests
    (Elsevier, 2025-05-15) Ibrahim, Khalifa Aliyu; Maréchal, Timothé Le; Luk, Patrick; Qin, Qing; Huang, Luofeng; Xie, Ying; Verdin, Patrick; Luo, Zhenhua
    The maritime industry is under increasing pressure to decarbonise, presenting an important pathway of transforming the power systems from conventional marine fuels to electric-based. This study proposes an innovative solution to support maritime decarbonisation through the integration of a floating solar clean energy harnessing and wireless power transfer (WPT) technology for electric vessels. The paper presents the design and experimental tests of the integrated system specifically, based on a model of an electric yacht. This study provides an in-depth analysis of application of floating solar to provides an off-grid wireless power transfer system that can scale for larger vessels such as ferries. The off-grid modularity proposed enables scalable, flexible, and sustainable energy delivery for maritime applications and decarbonisation with specific attention to challenges in WPT alignment and environmental condition. Simulations using ANSYS Maxwell were performed to model the magnetic field interactions and ascertain the optimal power transfer efficiency. Subsequently, a reduced-scale prototype system was designed, built and tested in a wave tank. The experimental results demonstrated efficient wireless charging with an average efficiency of 82 %, and the docking system proved effective in maintaining alignment even when the ship has wave-induced motions. The findings support the feasibility of using floating solar WPT systems for maritime vessels and pave the way to larger-scale studies.
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    Heat transfer in unconventional geothermal wells: a double numerical modelling approach
    (Springer, 2021-06-02) Renaud, Théo; Verdin, Patrick; Falcone, Gioia
    Geothermal energy aims at producing electricity or heat from underground resources. Worldwide geothermal energy extraction and use is still limited, despite its estimated high potential. To date, the efficiency and viability of enhanced geothermal system (EGS) and deep unconventional geothermal resources (e.g. superheated/supercritical systems) via conventional heat recovery techniques have led to limited success due to technology issues. Research on superheated/supercritical geothermal systems is highly active in Europe, notably triggered by the Iceland Deep Drilling Project (IDDP) [1]. Supercritical resources could deliver more energy than conventional resources thanks to the increase of enthalpy and the sharp decrease of density around the critical point of water [2]. The first well from IDDP was drilled at a depth of 2072 m after unintentionally drilling into magma between 2092 and 2104 m. The wellhead temperature reached 450°CC, with a superheated steam at a pressure of 140 bars (Palsson et al. in Geothermics 49:23–30, 2014).
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    Heat transfer modelling of an unconventional, closed-loop geothermal well
    (2021-10-27) Renaud, Théo; Verdin, Patrick; Falcone, Gioia; Pan, Lehua
    With approximately 13 GW installed capacity worldwide in 2017, the geothermal energy sector represents less than 1% of the total renewable energy mix. Although the Enhanced Geothermal System (EGS) concept faces technical and economic validation challenges and suffers from public acceptance issues, such system is considered to have the capability to unlock the significant deep geothermal potential worldwide. The development of unconventional deep well designs can help to improve the efficiency and reliability of EGS systems. An integrated reservoir-wellbore approach to model alternative EGS well designs is key to assess their long-term hydraulic and thermal performance, particularly in unconventional geological settings. A coupled wellbore-reservoir simulator, T2WELL/EOS1, is used to compare the estimated energy recovery with experimental results available in the public domain from a downhole coaxial heat exchanger (DCHE) installed in Hawaii, where a temperature of 358°C has been measured at a depth of 1962 m. Numerical results are also compared with analytical-based results from the literature, showing good agreement and demonstrating that the heat recovery from deep borehole heat exchangers can be accurately simulated. Thermal performance and economic viability of a hypothetical DCHE with conducting fillers in high thermal gradient areas are also discussed, based on the results from the Hawaii case study. The findings provide guidance to assess the operating range of closedloop single-well EGS designs in future studies.
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    Surrogate-based design optimisation tool for dual-phase fluid driving jet pump apparatus
    (Springer, 2019-11-22) Mifsud, Darren; Verdin, Patrick
    A comparative study of four well established surrogate models used to predict the non-linear entrainment performance of a dual-phase fluid driving jet pump (JP) apparatus is performed. A JP design flow configuration comprising a dual-phase (air and water) flow driving a secondary gas-air flow, for which no one has ever provided a unique set of design solutions, is described. For the construction of the global approximations (GA), the response surface methodology (RSM), Kriging and the radial basis function artificial neural network (RBFANN), were primarily used. The stacked/ensemble models methodology was integrated in this study, to improve the predictive model results, thus providing accurate GA that facilitate the multi-variable non-linear response design optimisation. An error analysis of all four models along with a multiple model accuracy analysis of each case study were performed. The RSM, Kriging, RBFANN and stacked models formed part of the surrogate-based optimisation, having the entrainment ratio as the main objective function. Optimisation problems were solved by the interior-point algorithm and the genetic algorithm and incurred a hybrid formulation of both algorithms. A total of 60 optimisation problems were formulated and solved with all three approximation models. Results showed that the hybrid formulation having the level-2 ensemble Kriging model performed best, predicting the experimental performance results for all JP models within an error margin of less than 10 % in 90 % of the cases.