Browsing by Author "Peralta, Ignacio"

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    Computational design of a massive solar-thermal collector enhanced with phase change materials
    (Energy and Buildings, 2022-11-01) Peralta, Ignacio; Fachinotti, Víctor D.; Koenders, Eduardus A. B.; Caggiano, Antonio
    A cement-based device that can meet, partially or completely, the heating loads of a building by absorbing the solar radiation and converting it into thermal energy can be defined as a Massive Solar-Thermal Collector. The absorbing material for the incoming radiation is made of a cementitious composite, generally concrete, and flowing water inside tubes acts as a heat transfer medium. For an optimized performance, during periods of solar radiation, the device has to efficiently conduct the heat flow from the absorbing surface of the collector and transfer this heat energy to the water. Then, when the radiation is reduced or became null, the device should retain as much as possible the heat energy, reducing the heat that is escaping the collector and consequently the losses to the surrounding environment. In this work, by performing a parametric analysis, different absorbing materials are tested with the objective of finding the best configuration that maximizes the energy efficiency of the collector. Cementitious materials, in combination with Phase Change Materials with distinct melting (and solidification) temperatures, are selected as candidate absorbing materials. The weather variables of an entire year and for two different locations are considered to evaluate the behavior of these devices in opposite climates. After numerical simulations, in where an enthalpy-based finite element formulation is used to solve the physical problem, the obtained results allow to conclude that the inclusion of Phase Change Materials within the absorber material of the collectors, if it is done in a correct way, can improve the energy performance of these devices. In this study, 34 ºC and 53 ºC are chosen as the most appropriated melting temperatures, which conduct to considerable improvements in the achieved performances, and in both warm and cold climates.
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    Computational design of building envelopes as thermal metamaterials
    (SynerCrete 2023, 2023-06-11) Fachinotti, Víctor D.; Álvarez-Hostos, Juan C.; Peralta, Ignacio; Caggiano, Antonio
    A metamaterial is a composite with unprecedented properties, either in nature or in the market. Specifically designed, a metamaterial exhibits either extraordinary or “à la carte” macroscopic physical properties, or allows the device made of it (the “metadevice”) to have an optimal response. In the context of the thermal performance of a building, let the metadevice be the whole building envelope, say the “metaenvelope”. Then, the metamaterial in the metaenvelope is determined in order to maximize the building energy efficiency. To this end, we apply the optimization-based metamaterial design approach, which consists in solving a nonlinear constrained optimization problem where the objective function is the energy consumption for cooling and heating, and the design variables define the metamaterial in the envelope. Particular emphasis is given to the use of NRG-foams, which are foamed concretes with embedded microencapsulated phase change materials developed within the framework of the EU H2020 project NRG-STORAGE. Finally, metaenvelopes having NRG-foams as insulation materials will be compared with a standard envelope in terms of the energy consumed by the enclosed building to keep the indoor thermal comfort.