Browsing by Author "Albanesi, Alejandro E."

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    A regularized approach for derivative-based numerical solution of non-linearities in phase change static hysteresis modeling
    (International Communications in Heat and Mass Transfer, 2025-04) Dittler, Ramiro A.; Demarchi, María Cecilia; Álvarez-Hostos, Juan C.; Albanesi, Alejandro E.; Tourn, Benjamín A.
    Phase change materials (PCMs) represent a promising solution for thermal energy storage (TES) since they can store and release energy in the form of latent heat during solid↔liquid transitions. Nevertheless, accurately simulating the thermal behavior of PCMs remains challenging due to the non-linearities concerning latent heat effects and enthalpy hysteresis. This work introduces a stable and robust procedure based on the finite element method (FEM) under a mixed enthalpy–temperature formulation to address such non-linearities, which enables the numerical solutions using derivative-based algorithms such as the Newton–Raphson (NR) method. The static hysteresis model (SHM) is implemented in the FEM-based formulation via a regularization of the liquid fraction function in response to the sign of the temperature rate. This novel approach ensures a continuous and smooth heating↔cooling transition while retaining the SHM energy-conservative features to properly solve its non-linearities. The method is validated through a one-dimensional benchmark problem, demonstrating high performance and physical fidelity for both complete and partial phase changes. It achieves second-order convergence rates, ensures numerical stability even for large time steps, and maintains accuracy under diverse thermal boundary conditions. Finally, the method is extended to two-dimensional problems, highlighting its robustness and scalability for practical applications in TES systems.
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    A shot in the dark : the current state of PCM hysteresis modelling in building energy simulation software
    (2025-02-16) Zhilyaev, Dmitry; Albanesi, Alejandro E.; Demarchi, María Cecilia; Fachinotti, Víctor D.; Bakker, Hans L. M.; Jonkers, Henk M.
    Phase change materials (PCM) are receiving an ever-growing attention as a promising construction material for improving building energy performance through thermal storage and peak load shifting. The analysis of PCM performance and decision-making related to PCM implementation in building envelope often rely on building energy simulation software such as EnergyPlus – a de-facto standard in the academic world and the industry. For a precise modelling of the dynamic PCM behaviour it is essential to correctly account for PCM hysteresis. This work provides an in-depth analysis of four publicly available EnergyPlus-based hysteresis models and identifies the existing limitations for each of them. Furthermore, it explores the effects of PCM model selection on decision-making using the example of novel PCM-embedded material development. The results of this study show that the current built-in hysteresis model in EnergyPlus is not implemented correctly, and none of the other analysed models is completely free of limitations. Moreover, this work draws attention to the existing contradictions between different PCM modelling approaches, highlighting the critical impact the selection of a PCM model has on PCM-related decision-making. We conclude that while the existing hysteresis models in EnergyPlus are operable – albeit with great caution – they are not yet at the stage where they could be used as a reliable decision-making support tool. Practical real-world integration of PCM in building envelopes is hardly possible without having dependable modelling tools to back it up, and the development of such tools requires far more attention than it is given at the moment.
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    Análisis del desempeño energético de la ventilación en galpones tipo granja avícola mediante simulación por computadora
    (JIT, 2022-11-03) Hernández Beltramino, Franco; Demarchi, María Cecilia; Albanesi, Alejandro E.
    La ventilación y renovación del aire juega un papel crucial en el control de la temperatura, humedad y la contaminación del aire dentro de las granjas avícolas. Este trabajo presenta los resultados preliminares de la valoración energética de granjas avícolas a través de la simulación computacional. El objetivo de esta valoración es minimizar el consumo energético de las granjas. El desempeño energético de los distintos escenarios de trabajo se mide a partir del consumo de energía necesaria para mantener la temperatura en el rango aceptable que demanda la producción, a partir de un modelo que simboliza las condiciones reales de operación del galpón.
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    Enhancing the accuracy of thermal model calibration: Integrating zone air and surface temperatures, convection coefficients, and solar and thermal absorptivity
    (Energy and Buildings, 2025-06-01) Demarchi, María Cecilia; Gervaz Canessa, Sofía; Pena Vergara, Gabriel; Albanesi, Alejandro E.; Favre, Federico
    Building energy simulation models are indispensable tools for predicting thermal and energy performance and evaluating building energy efficiency. However, in the calibration and sensitivity analysis of these models, most studies focus on air temperatures or energy consumption, typically not taking into account critical parameters such as surface temperatures, convective heat transfer coefficients, and thermal and solar absorptivities. In this context, this work complements prior studies by incorporating these critical parameters, including convection coefficients and thermal and solar absorptivity, enhancing both the reliability and completeness of building simulation models. Using a monitoring period, air and surface temperature data were collected under free-floating conditions and supplemented with meteorological records from an on-site station. Optimization was performed using the root mean square error (RMSE) metric to minimize discrepancies between measured and simulated values of zone air and surface temperatures. The results demonstrate that the detailed calibration strategy, which considers convective coefficients and material absorptivities as design variables and minimizes errors in both air and surface temperature predictions, significantly enhances model accuracy. This approach reduces the RMSE of air temperature predictions by 60 % and the RMSE of surface temperature predictions by 73 % (walls), 79 % (inner roof), 42 % (outer roof), and 82 % (floor). Further analysis of heat gains and losses emphasizes the critical role of these parameters in the accuracy in the modeling of building-environment interactions. This detailed and robust approach ensures a more precise and reliable simulation model, highlighting the critical role of advanced calibration techniques in optimizing building energy performance simulations.
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    Modelo inverso iterativo acoplado a algoritmo genético para la calibración de modelos de simulación térmica de edificios
    (XL MECOM, 2024-11-08) Demarchi, María Cecilia; Albanesi, Alejandro E.; Favre, Federico; Álvarez-Hostos, Juan C.
    En este estudio se implementa un modelo inverso iterativo basado en optimización con algoritmo genético para la calibración y validación de modelos de simulación computacional del rendimiento térmico de edificios. Este modelo ajusta dinámicamente las resistencias térmicas del aire, la absortancia térmica y solar de los materiales exteriores, la infiltración de aire y el coeficiente convectivo para minimizar las discrepancias entre las temperaturas de aire medidas y simuladas. Este meticuloso enfoque garantiza una calibración precisa y una evaluación efectiva del rendimiento térmico y energético del modelo, proporcionando información valiosa para la optimización de las estrategias de diseño energético de edificios. Se considera como caso de estudio los edificios construidos en Bulgaria, Sofia, en el marco del proyecto NRG STORAGE (Integrated porous cementiciuos Nanocomposites in non-Residential building envelopes for Green active/pasive energy STORAGE).
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    Simulación computacional del rendimiento energético de espumas cementicias con PCM microencapsulado incorporado como materiales aislantes de envolventes de edificios
    (JIT, 2023-10) García Girard, Ignacio; Berardo, Santiago; Demarchi, María Cecilia; Albanesi, Alejandro E.
    Este estudio aborda la importancia de mejorar la eficiencia energética en edificios debido al crecimiento de la población y su impacto en el consumo de energía y la contaminación. Se enfoca en el uso de materiales con cambio de fase (PCM) en las envolventes de los edificios como una solución prometedora. Los PCM pueden almacenar y liberar energía, reduciendo el consumo de energía y siendo respetuosos con el medio ambiente. El estudio analiza el comportamiento térmico de espumas cementicias con PCM en tres climas de Argentina y compara sus resultados con aislantes convencionales. Se utiliza el modelo ANSI/ASHRAE BESTEST 900 para medir el consumo de energía y se evalúan las ventajas y desventajas de estos compuestos en cada zona climática.