Browsing by Keyword "phase change materials"
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Item Cement Based Materials with PCM and Reduced Graphene Oxide for Thermal Insulation for Buildings(Springer Science and Business Media B.V., 2023) Erkizia, Edurne; Strunz, Christina; Dauvergne, Jean Luc; Goracci, Guido; Peralta, Ignacio; Serrano, Ángel; Ortega, Amaya; Alonso, Beatriz; Zanoni, Francesca; Düngfelder, Michael; Dolado, Jorge S.; Gaitero, Juan Jose; Mankel, Christoph; Koenders, Eduardus; ECOEFICIENCIA DE PRODUCTOS DE CONSTRUCCIÓN; Tecnalia Research & InnovationEnergy demand for heating and cooling represents a large part of building´s (residential and non-residential) energy consumption around the world. Development of thermal insulating construction elements with thermal energy storage and release capacity could be one way of reducing this consumption while maintaining thermal comfort inside the buildings. Using phase change materials (PCMs) as thermal storage/release materials for “porous” cement-based construction elements is a possible solution. However, the relatively low thermal conductivity of the cement matrix could impair the efficient transfer of the heat to the PCM reducing its effectivity. Addition of thermal and electrically conductive nanoparticles such as graphene-based particles could improve enough the thermal and electrical conductivity but maintain a good energy storage capacity. In this study the production of cement pastes with different dosage of PCMs (20% and 40% in volume) and reduced graphene oxide will be described. Furthermore, the characterization of their thermal and electrical conductivity, latent heat and thermal diffusivity will also be shown and discussed.Item Feasibility of Storing Latent Heat with Liquid Crystals. Proof of Concept at Lab Scale(2016-05) Bayon, Rocio; Coco, Silverio; Barcenilla, Maria; Espinet, Pablo; Imbuluzqueta, Gorka; Hidalgo, Jokin; Rojas, Esther; SISTEMAS FOTOVOLTAICOS; VALORIZACIÓN DE RESIDUOSIn this work, the first experimental results of thermotropic liquid crystals used as phase change materials for thermal storage are presented. For that purpose, the n = 10 derivative from the family of 4-n-alkoxybiphenyl-4-carboxylic acids has been prepared. Different techniques like polarized-light microscopy, differential scanning calorimetry, thermogravimetric analysis and rheological measurements have been applied for its characterization. Having a mesophase/isotropic transition temperature around 251 degrees C, a clearing enthalpy of 55 kJ/kg, a thermal heat capacity of around 2.4 kJ/kg and a dynamic viscosity lower than 0.6 Pas, this compound fulfills the main requirements for being considered as latent heat storage material. Although further studies on thermal stability are necessary, the results already obtained are both promising and encouraging since they demonstrate de viability of this new application of liquid crystals as thermal storage media.Item Thermal storage nanocapsules by miniemulsion polymerization(2013-03-15) De Cortazar, Maider García; Rodríguez, Raquel; CIRMETAL; POLIMEROSParaffin wax was nanoencapsulated by miniemulsion polymerization. Low solid content batch polymerizations were carried out and the influence of paraffin wax/methyl methacrylate ratio on polymeriztion kinetics, phase change properties, and thermal stability were investigated. Paraffin concentration controls the nucleation mechanism and nanocapsules particle size. The latent heat capacity increases as the content of encapsulated paraffin wax increases. The maximum amount of encapsulated paraffin wax achieved under the experimental conditions was 60 wt %, presenting a latent heat capacity of 140.3 J/g. Moreover, the encapsulated systems present in all cases better thermal stability than pure paraffin wax. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013