Browsing by Author "CHEHHAT, Abdelmadjid"

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    Feasibility study of green hydrogen production using renewable energy source solar-energy: A case study of Khenchela, Algeria
    (2026) CHEHHAT, Abdelmadjid
    The global transition toward carbon neutrality has positioned green hydrogen as a promising energy carrier capable of supporting renewable energy integration and contributing to the decarbonization of hard-to-abate sectors. In this context, this study investigates the feasibility of green hydrogen production using solar photovoltaic energy in Khenchela, Algeria, through a 3E concept: Energy, Economy, and Environment. The proposed system consists of a utility-scale photovoltaic plant directly coupled to a Proton Exchange Membrane PEM electrolyzer, supported by hydrogen compression and storage units. A Python-based hourly simulation model was developed and applied over a 25-year project lifetime using photovoltaic generation data obtained from the System Advisor Model SAM. The analysis incorporates system operation, hydrogen production, energy curtailment, component replacement, discounted cash flow modeling, and environmental impact assessment. The results indicate that the system can produce approximately 15.43 million kg of green hydrogen over its lifetime, with an average annual production of about 617,000 kg. The electrolyzer operates with a capacity factor of 34.84%, while the overall solar-to-hydrogen efficiency reaches approximately 56.3%. The Levelized Cost of Hydrogen LCOH is estimated at 7.68 USD/kg, with capital expenditures representing the largest cost contribution. Financial analysis shows that project profitability is achieved only under higher hydrogen selling prices, highlighting the strong influence of market conditions on economic viability. Sensitivity analysis identifies electrolyzer energy consumption and capacity factor as the most influential parameters affecting hydrogen production costs. From an environmental perspective, the proposed system avoids approximately 390,706 tonnes of CO₂ emissions over the project lifetime compared with electricity supplied by the Algerian grid. Overall, the findings confirm the technical feasibility and environmental benefits of solar-based green hydrogen production in northeastern Algeria, while emphasizing the need for cost reductions and supportive policies to improve economic competitiveness.
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    Study of geothermal energy piles performances using CFD (Etude des performances des pieux à énergie géothermique par utilisation de la CFD)
    (2025) CHEHHAT, Abdelmadjid
    Geothermal energy piles (GEPs), which integrate structural foundation elements with ground heat exchangers, represent a sustainable and efficient solution for building heating and cooling by harnessing the relatively stable subsurface soil temperature. This study offers a comprehensive parametric and multi-physics investigation into both the thermal and thermomechanical behavior of GEPs under seasonal operating conditions. It is divided into three main parts, using advanced numerical simulations within ANSYS Workbench. In the first part, the transient thermal response of GEPs during summer and winter is analyzed using Computational Fluid Dynamics (CFD) in ANSYS Fluent, assessing the impact of varying flow regimes (Reynolds numbers from 500 to 2000) on outlet temperature and heat transfer rate. Results indicate that higher flow velocities increase the heat transfer rate but reduce thermal exchange efficiency due to shorter fluid residence time. The second part focuses on parametric CFD optimization of key geometric parameters, pile diameter, heat exchanger diameter, pipe-toconcrete spacing, and pipe angular orientation. Supported by analytical modeling, simulations identify the optimal configuration (400 mm pile diameter, 26 mm pipe diameter, 20 mm spacing, and 30° orientation), yielding improved thermal performance in both heating and cooling scenarios. Strong correlation between CFD and analytical results confirms the model’s validity. The third part involves a coupled thermo-mechanical analysis, evaluating the structural response of GEPs with circular, square, and triangular U-shaped pipe geometries through twoway coupling between ANSYS Fluent (thermal input) and Static Structural (mechanical analysis). Findings reveal that pipe geometry significantly influences both heat transfer and stress distribution. The triangular configuration demonstrates superior cooling efficiency due to enhanced internal convection but introduces localized stress concentrations that require structural consideration. Seasonal thermal loads induce geometry-dependent axial and shear stress patterns, with maximum displacement consistently occurring at the pile base. Overall,