Browsing by Author "Segovia Araya, Valentina Constanza"

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    Analysis of copper slag from a Chilean foundry for application as filler material in thermal energy storage systems
    (2025) Segovia Araya, Valentina Constanza; Cardemil Iglesias, José Miguel; Sancy, Mamié; Escobar Moragas, Rodrigo
    In the field of solar thermal storage systems, metallurgical industry by-products have been proposed as filler materials for packed-bed thermal energy storage due to their low cost and suitable thermophysical properties. One of these by-products is copper slag, which has emerged as a competitive option compared to other types of industrial by-products. However, further research of its properties, composition, and heterogeneity is needed to fully address its potential as a storage medium. Approximately 2.2 tons of copper slag is produced per ton of copper extracted, posing disposal challenges for mining companies. Hence, there is growing interest in finding secondary uses for these slags. The present study investigated samples of copper slag from a Chilean foundry disposal site. Elemental and mineral characterization revealed that this heterogeneous material has high iron content with both amorphous and crystalline phases present. The evaluation of thermophysical properties showed stable specific heat capacity that increases with temperature within the range of 100 °C to 450 °C. However, these profiles exhibit variability in heat capacity, particularly at higher temperatures, which decreases with subsequent heating cycles. The results suggest that copper slag has potential as an alternative material for sensible heat storage in packed-bed systems, nonetheless, assessing the variability of its thermophysical properties is crucial to establish its feasibility for sustainable energy solutions.
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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.