Low temperature energy storage by bio-originated calcium alginate-octyl laurate microcapsules (original) (raw)

Journal of Thermal Analysis and Calorimetry

Octyl laurate phase change material (PCM) was microencapsulated by calcium alginate for eco-friendly low temperature energy storage. The PCM microcapsules were prepared by repeated interfacial coacervation followed by crosslinking method. In order to enhance the antibacterial properties of the as prepared capsules, the calcium alginate shell was functionalized by Ag nanoparticles. Calcium alginate-octyl laurate microcapsules possessed high latent heat of fusion values (130.8 and 128.6 J g−1 on melting and cooling, respectively) which did not significantly change when Ag nanoparticles were entrapped in the shell (127.5 and 125.2 J g−1 for melting and freezing enthalpy changes). Based on these values 71.0 and 69.0% maximal PCM content in the microcapsules were determined by the differential scanning calorimetry method. Both of the Ag-loaded and unloaded calcium alginate-octyl laurate PCM capsules maintained the high heat storing capacity after 250 warming and cooling cycles, which pro...

Preparation of calcium alginate microcapsules containing n-nonadecane by a melt coaxial electrospray method

Journal of Electrostatics, 2015

PCM microcapsule is prepared using a melt coaxial electrospray method.The microcapsules containing 56 wt% n-nonadecane and the diameter lower than 100 μm.Capsule diameter increased with alginate concentration and spinning distance.The shell and the core solution flow rates should be controlled during electrospray.A novel method called melt coaxial electrospray was used to produce phase change material (PCM) microcapsules with sodium alginate as the shell and n-nonadecane as the core. The effect of production parameters on microcapsule size and structure was studied. The microcapsules were characterized using optical microscopy and Fourier transform infrared (FTIR) spectroscopy. The thermal behavior of PCM microcapsules was measured by differential scanning calorimetry (DSC). The results of FTIR and DSC confirmed the successful melt coaxial electrospraying of PCMs. Careful control of production parameters yielded spherical PCM microcapsules with diameter lower than 100 μm and 56 ± 5% encapsulation ratio.

Green chemistry solutions for sol–gel micro-encapsulation of phase change materials for high-temperature thermal energy storage

Manufacturing Review, 2018

NaNO3 has been selected as phase change material (PCM) due to its convenient melting and crystallization temperatures for thermal energy storage (TES) in solar plants or recovering of waste heat in industrial processes. However, incorporation of PCMs and NaNO3 in particular requires its protection (i.e. encapsulation) into containers or support materials to avoid incompatibility or chemical reaction with the media where incorporated (i.e. corrosion in metal storage tanks). As a novelty, in this study, microencapsulation of an inorganic salt has been carried out also using an inorganic compound (SiO2) instead of the conventional polymeric shells used for organic microencapsulations and not suitable for high temperature applications (i.e. 300–500 °C). Thus, NaNO3 has been microencapsulated by sol–gel technology using SiO2 as shell material. Feasibility of the microparticles synthetized has been demonstrated by different experimental techniques in terms of TES capacity and thermal stab...

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