Browsing by Author "Calderon-Vasquez, Ignacio"

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    "An enhanced and optimized Monte Carlo method to calculate view factors in packed beds"
    (2023) Cortes, Eduardo; Gavino, David; Calderon-Vasquez, Ignacio; Garcia, Jesus; Estay, Danilo; Cardemil Iglesias, Jose Miguel; Barraza, Rodrigo
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    Application of layer view factor method in high temperature thermal storage packed bed
    (2024) Cortes, Eduardo; Gavino, David; Calderon-Vasquez, Ignacio; Garcia, Jesus; Estay, Danilo; Cardemil, Jose M.; Barraza, Rodrigo
    This study provides a comprehensive evaluation of radiation effects on the thermal behavior of a packed bed using a discrete model for heat transfers integrating a novel method called Layer View Factor for view factors estimation, which significantly decreases computational time by less than 9000 times compared to the parallel ray tracing method. The model is validated and strongly aligned with experimental data at 823 K, with a maximum mean bias and root mean square errors of +/- 4.5 K and 10 K, respectively. Analyses of temperature profiles and thermocline lengths for charging, discharging, and stand-by processes at a charge temperature of 1473 K were performed, finding a thermal flattening effect with radiation, leading to lower peak temperatures and quicker thermocline length evolutions. Notably, the stand-by process exhibited the largest impact, with a maximum temperature difference of up to 100 K compared to the non-radiation case. Moreover, analysis of the temperature and energy of discharge found that the maximum discharge temperature drops below 90% of the charge temperature when radiation is included. Finally, efficiency analysis of the processes showed differences of up to 2% between having or not the radiation effect, aiming its role as a redistribution mechanism in the packed bed's temperature.
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    Design and assessment of a concentrating solar thermal system for industrial process heat with a copper slag packed-bed thermal energy storage
    (2024) David-Hernandez, Marco A.; Calderon-Vasquez, Ignacio; Battisti, Felipe G.; Cardemil, Jose M.; Cazorla-Marin, Antonio
    Decarbonising the industrial sector is a key part of climate change mitigation targets, and Solar Heat for Industrial Process (SHIP) is a promising technology to achieve this. However, one of the drawbacks of SHIP systems is that they rely on an intermittent energy source. Therefore, sensible energy storage has emerged as a potential solution. In addition, solid byproducts have been proposed as a low-cost but effective material for thermal energy storage (TES). This work presents a SHIP system model coupled with a copper slag-packed-bed TES (PBTES) model using air as heat transfer fluid. The TES has been implemented to preheat the makeup water of the tank where steam is generated. A system design was carried out using a parametric analysis to find a solar field size and a corresponding TES volume. The resulting system was simulated, and the operating variables were analysed in detail. The results show that it is possible to generate 20% more energy due to the storage system. Additionally, a techno-economic analysis indicates that the SHIP with PBTES system results in a payback period of 14 years and a savings of CO2 emissions of 30 t CO2.
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    On the analytical solution of the one-dimensional convection-conduction equation for packed-bed thermal energy storage systems
    (2024) Calderon-Vasquez, Ignacio; Battisti, F. G.; Rosales-Vera, Marco; Cardemil, Jose M.; Escobar, Rodrigo
    Temperature distribution modeling within packed-bed thermal energy storage (PBTES) systems is crucial to simulate its integration into heat sources and perform techno-economic analyses to assess the actual benefits associated with its use. This article proposes a one-dimensional convection-conduction equation to model a fluid-solid system by assuming volume-averaged properties for the energy balance and determines the analytic solution through Integral Transforms. The present study analyzes the applicability of this analytic solution considering different operational conditions of PBTES systems. The article revealed that the P & eacute;clet number (Pe) and the fluid-to-solid capacity ratio (kappa) must be limited to obtain stable solutions, while the dimensionless time tau cannot be arbitrary despite computing an analytic solution. A sensitivity study of the solution for parameter a=kappa Pe/2 defined the minimum dimensionless time required for the solution to be stable. This stability was assessed with existing experimental setups, indicating the solution's feasibility for air-solid PBTES systems.
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    Review on modeling approaches for packed-bed thermal storage systems
    (2021) Calderon-Vasquez, Ignacio; Cortes, Eduardo; Garcia, Jesus; Segovia, Valentina; Caroca, Alejandro; Sarmiento, Cristobal; Barraza, Rodrigo; Cardemil Iglesias, Jose Miguel