Browsing by Author "Calderón Vásquez, Ignacio Andrés"

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    Modelling the temperature distribution in a horizontal packed-bed thermal energy storage system with copper slag as filler material
    (2025) Calderón Vásquez, Ignacio Andrés; Wolde Ponce Ian; Segovia Araya, Valentina Constanza; Battisti, F. G.; Cardemil Iglesias, José Miguel; Escobar Moragas, Rodrigo Alfonso
    Air-solid packed-bed thermal energy storage (PBTES) systems are potential candidates to reduce implementation costs for renewable energy applications. However, heat transfer modelling requires high computational resources, which makes these models unsuitable for control and management in integrated systems. This work presents a fit parameter estimation model to predict the temperature distribution on an operational PBTES system. Through the non-linear least squares method, we use experimental data to calibrate an analytical solution for the heat exchange within an air-solid porous medium. This model presented a normalised root mean squared error of 4% to predict the temperature and the state of charge (SOC). Using mean values from the mass flow rate time series, the model allows estimating the SOC with a deviation of 0.5% from the one calculated from experimental data, and predicted that approximately 60% of the discharged energy was recovered from the storage tank walls, despite not explicitly modelling them. The proposed model avoids solving differential equations by directly computing the analytical solution, making it computationally efficient. Its accuracy and simplicity make it a strong candidate for integration into control and energy management systems for PBTES technologies.
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    Operational dynamics of packed-bed thermal energy storage: A novel approach to monitor its thermal state
    (2025) Calderón Vásquez, Ignacio Andrés; Battisti, Felipe G.; Escobar Moragas, Rodrigo; Cardemil Iglesias, José Miguel
    Heating solids arranged in a packed bed is a simple method to store sensible thermal energy. This study focuses on cylindrical packed-bed configurations, where a temperature profile develops along the stacked solids and moves towards the system's outlet. Therefore, the availability to store thermal energy in the packed bed decreases over time and the exhaust energy outside the storage increases. To address this challenge, the present work introduces a novel operational metric to monitor the thermal state of packed-bed storage systems. This operational metric relates the stored potential in the system with an ideal stage, and its definition enables constraining the system's operation with a simple mathematical condition, which is a significant outcome from the traditional approach of using arbitrary temperature limits to stop the charging process. Its calculation requires the measurement of the top and bottom temperatures of the packed bed and knowing the system's maximum operating temperatures. When applying the mathematical condition, the required charging time to reach that stage and the cut-off temperature can be obtained. A parametric analysis correlated these operating quantities to design data to predict their value given the design conditions. This work provides a new perspective on the dynamic operation of cylindrical packed-bed sensible thermal energy storage systems, offering a simple yet effective strategy to enhance system performance.