Preparation and thermal reliabilities of microencapsulated phase change materials with binary cores and acrylate-based polymer shells

Summary For passive building applications, phase change materials (PCMs) are microencapsulated to avoid leakage of PCM from concrete structure. The primary challenge of using microencapsulated PCM (MPCM) is its weak shell structure. New MPCMs with different shell compositions to prevent breakage during mixing in fresh concrete are needed. In this study, free radical polymerization method to microencapsulate capric acid–myristic acid mixture as PCM with two different methyl methacrylate co‐polymers is proposed to produce robust MPCMs for building applications. Two new microcapsules (MPCM‐1 and MPCM‐2) having latent heats of 91.9 and 97.3 J/g were synthesized. SEM analyses showed the size of microcapsules being in the range of 400–850 nm for MPCM‐1 and 250–475 nm for MPCM‐2. Analyses also reveal that the shells of MPCMs were not harmed, as they were added into concrete mixes. The microsphere's geometry was preserved, and distribution was homogeneous. The MPCMs were also studied under thermal tests of 1000 heating/cooling cycles. No significant changes in thermal properties were observed after thermal cycling tests. Copyright © 2016 John Wiley & Sons, Ltd.

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“…• suspension-like polymerization [22]; • interfacial polymerization [23]; and • emulsion polymerization [18].…”

Section: Introductionmentioning

confidence: 99%

Robust microencapsulated phase change materials in concrete mixes for sustainable buildings

Beyhan

Cellat

Konuklu

et al. 2016

Int. J. Energy Res.

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“…In microencapsulation, the core material is defined as the specific material to be coated and can be in liquid or solid state depending on the temperature. The composition of the solid core can be a single solid substance or a mixture of active constituents, stabilizers, diluents, excipients and release-rate retardants or accelerators [41,42]. There are three type of PCM: organic, inorganic and eutectic PCM.…”

Section: Types Of Phase Change Materials (Pcm)mentioning

confidence: 99%

Types, methods, techniques, and applications for microencapsulated phase change materials (MPCM): A review

Giró-Paloma

Martínez

Cabeza

et al. 2016

Renewable and Sustainable Energy Reviews

450

151

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Phase Change Materials (PCM) can be employed in many fields because of their capacity to absorb and release energy when it is necessary. Nowadays, the number of studies about these materials is increasing because of their benefits in energy systems. This paper reviews the previous researches and developments on microencapsulated phase change materials (MPCM) in thermal energy storage (TES) systems, focusing on the different methods of encapsulations and also the different applications of these materials. This review aims to be a useful guide for the researchers in this area, because it explains the different types of phase change core materials, the different shells, the methods to microencapsulate these PCM, the most used techniques to characterize these microencapsulated phase change materials, and a revision of the main applications.Storage these type of materials to store energy, and release it when the systems needed, for example, the chilly bins studied by Oró et al. [15] to enhance the thermal performance. Also, it is possible to use phase change materials in cold storage needs, as Oró et al. [16] evaluate, studying the compatibility of PCM with metallic materials, but a common problem in PCM cooling applications is the subcooling, which happens when a material is cooled and the crystallization does not start below the freezing temperature [17].Another very significant application of PCM is the one in the building sector [18], in passive applications like floors [19], walls [20-23] (for example conventional and alveolar brick [24]), and ceiling studies. There is another case, which is in active systems in domestic applications as heating [25] and hot water [26][27][28][29].Since PCM undergo the solid-liquid states, they need to be encapsulated for their inclusion in the final system. Due to the leakage in the liquid state when mixing the PCM with other materials, such as building construction materials [30], and because of the corrosion and the thermal reliability, the possibility to make a polymeric container for PCM, in small vessels, using the encapsulation technology and producing capsules calling them encapsulated Phase Change Material for energy storage [31] has been investigated. Encapsulation techniques vary from macroencapsulation in slabs, panels, etc. to microencapsulation [32,33]. When the sizes of these capsules are micrometers, these are called Microencapsulated Phase Change Material (MPCM), which consisted on a polymeric shell and a core made of the storage material. The microencapsulation is a process of enclosing micron-sized particles of solids or droplets of liquids or gases in an inert shell, which in turn isolates and protects them from the external environment. The captivity of waxes into the microcapsules allows to increase the heat transfer[3] and to control de volume changes when the phase change is happening. Microencapsulation methodology for PCM still needs to be improved because the microcapsules can break easily when they collide with other microcapsules when they are used in...

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“…It is noteworthy that the bowl-like shell is uncommon in the crystal forms of CaCO 3 . This is because the phase separation occurred when CaCl 2 reacted with Na 2 CO 3 [37]. The phenomena indicated that binary cores weight ratio and reaction temperature were the key factors of the formation of CaCO 3 crystal forms, and also led to various crystalline structures of CaCO 3 and different morphologies of the micro-PCMs.…”

Section: Synthesis and Microstructurementioning

confidence: 99%

Microencapsulation of phase change materials with binary cores and calcium carbonate shell for thermal energy storage

et al. 2016

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Preparation and thermal reliabilities of microencapsulated phase change materials with binary cores and acrylate-based polymer shells

Cited by 47 publications

References 42 publications

Robust microencapsulated phase change materials in concrete mixes for sustainable buildings

Robust microencapsulated phase change materials in concrete mixes for sustainable buildings

Types, methods, techniques, and applications for microencapsulated phase change materials (MPCM): A review

Microencapsulation of phase change materials with binary cores and calcium carbonate shell for thermal energy storage

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