Browsing by Keyword "thermal energy storage"
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Item Characterization of Fatty Acids as Biobased Organic Materials for Latent Heat Storage(2021-08-20) Duquesne, Marie; Mailhé, Clément; Doppiu, Stefania; Dauvergne, Jean-Luc; Santos-Moreno, Sergio; Godin, Alexandre; Fleury, Guillaume; Rouault, Fabien; Palomo del Barrio, Elena; Tecnalia Research & Innovation; BIOECONOMÍA Y CO2This work aims to characterize phase change materials (PCM) for thermal energy storage in buildings (thermal comfort). Fatty acids, biobased organic PCM, are attractive candidates for integration into active or passive storage systems for targeted application. Three pure fatty acids (capric, myristic and palmitic acids) and two eutectic mixtures (capric-myristic and capric-palmitic acids) are studied in this paper. Although the main storage properties of pure fatty acids have already been investigated and reported in the literature, the information available on the eutectic mixtures is very limited (only melting temperature and enthalpy). This paper presents a complete experimental characterization of these pure and mixed fatty acids, including measurements of their main thermophysical properties (melting temperature and enthalpy, specific heats and densities in solid and liquid states, thermal conductivity, thermal diffusivity as well as viscosity) and the properties of interest regarding the system integrating the PCM (energy density, volume expansion). The storage performances of the studied mixtures are also compared to those of most commonly used PCM (salt hydrates and paraffins).Item The influence of mixing water on the thermophysical properties of nanofluids based on solar salt and silica nanoparticles(AMER INST PHYSICS, 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA, 2016-05-31) Muñoz-Sánchez, Belen; Nieto-Maestre, Javier; Iparraguirre-Torres, Iñigo; Sanchez-Garcia, Jose Angel; Julia, Jose Enrique; García-Romero, Ana; Rajpaul, Vikesh; Richter, Christoph; Tecnalia Research & Innovation; VALORIZACIÓN DE RESIDUOSThe use of nanofluids (NFs) based on Solar Salt (SS) and nanoparticles (NPs), either as Thermal Energy Storage (TES) material or as Heat Transfer Fluid (HTF), is attracting great interest in recent years. Many authors [1,3] have reported important improvements on the thermophysical properties (specific heat capacity cp,thermal conductivity k) of NFs based on SS and ceramic NPs. These improvements would lead to important savings and better performance of TES facilities on new Concentrated Solar Power (CSP) plants due to lower quantities of material required and smaller storage tanks. To achieve these advantageous features in the final NFs, it is essential to avoid NP agglomeration during their preparation. Different synthesis procedures have been reported: mixing of solid NPs within a SS solution by means of ultrasounds [1-3], direct mixing of solid NPs and molten salt [4]. In this work, NFs based on SS and 1% by wt. of silica NPs were synthetized from a SS-water solution and a commercial water-silica NF called Ludox HS 30% (Sigma-Aldrich). The influence of the mixing water volume (MW) on the cp of NFs was evaluated. With this aim, the cp of these samples was measured by Differential Scanning Calorimetry (DSC) both in the solid and the liquid state. In addition, the distribution of sizes was measured during the whole preparation process by Dynamic Light Scattering (DLS). Further information about sizes and uniformity of the final NFs was obtained from Scanning Electron Microscopy (SEM) images. X-ray Diffraction (XRD) patterns of the SS and final NF were performed.Item Preparation of nanofluids based on solar salt and boehmite nanoparticles: Characterization of starting materials: Characterization of starting materials(AMER INST PHYSICS, 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA, 2016-05-31) Muñoz-Sánchez, Belen; Nieto-Maestre, Javier; Iparraguirre-Torres, Iñigo; Sanchez-Garcia, Jose Angel; Julia, Jose Enrique; García-Romero, Ana; Rajpaul, Vikesh; Richter, Christoph; Tecnalia Research & Innovation; VALORIZACIÓN DE RESIDUOSA nanofluid composed of Solar Salt (SS) and boehmite nanoparticles (A) in a concentration of 1% by weight, is proposed as thermal storage medium for Concentrated Solar Power (CSP) plants. A wide characterization of the raw materials has been done, focused on their thermal stability and the nanoparticle primary size and shape among other properties such as its specific heat and crystalline structure. Some features of the final nanofluids have been also investigated: thermal stability, nanoparticle sizes and their distribution and specific heat. The showed results confirm that these materials are thermally stable in the working temperature range both individually and combined. In addition, the synthesis procedure implemented is effective to keep the nanoparticle sizes in the nanometric range (<100 nm). These findings mean the first step to carry on research and characterization of this nanofluid.Item Sustainable lignin-based polyols as promising thermal energy storage materials(2021-12-10) Perez-Arce, Jonatan; Serrano, Angel; Dauvergne, Jean Luc; Centeno-Pedrazo, Ander; Prieto-Fernandez, Soraya; Palomo Del Barrio, Elena; Garcia-Suarez, Eduardo J.; Perez‐Arce, Jonatan; Centeno‐Pedrazo, Ander; Prieto‐Fernandez, Soraya; Garcia‐Suarez, Eduardo J.; Tecnalia Research & Innovation; GENERALSix lignin-based polyols (LBPs) have been prepared by cationic ring opening polymerization of an oxirane in the presence of an organosolv lignin in tetrahydrofuran (THF) as reaction media and co-monomer. The prepared LBPs have been characterized and tested for the first time as phase change materials (PCMs) for thermal energy storage (TES) at low temperature. It was found a strong influence of the LBPs composition on their performance to storage thermal energy. Thus, LBPs with higher THF wt% content and lower oxirane/THF mass ratio exhibit the highest latent heats. Furthermore, a clear inversely proportional trend between the oxirane/THF mass ratio and the melting temperatures of the prepared LBPs was noticed. Among the prepared LBPs, the highest obtained latent heat was 53.7 J/g demonstrating the potential application of lignin as feedstock for PCMs preparation. To the best of our knowledge, this is the first time that a biomass derived PCM based on lignin has been studied and considered for TES applications at low temperature. LBPs show energetic solid–liquid transitions that point out their promising potential as bio-PCMs. This work paves the way to introduce new bio-based PCMs from lignin in TES systems, for example, in a more sustainable construction sector.