Designing microcapsules to save energy in buildings

Buildings consume the major portıon of the world’s energy. Improvements in building elements have been proven to significantly reduce this consumption. Integrating phase change materials (PCM) into a building’s parts is an effective solution to reduce energy consumption. PCMs help to maintain thermal comfort, reduce heating, cooling loads as well as improve passive storage of solar energy in buildings. Previous studies have concentrated on impregnating PCMs into materials like concrete mixes, gypsum wall boards, plasters, textured finishes, as well as PCM trombe walls, PCM shutters, PCM building blocks, air-based heating systems, floor heating systems, suspended ceiling boards, etc.[1]. The current challenge is to find a suitable PCM that can be safe, thermally effective and at the same time not adversely effect the durability of a building. PCMs may be in microcapsulated form to meet these challenges. The most common PCM studied previously is paraffin, be it in bulk or microencapsulated. Leakage of paraffin from porous structures, the breaking of microcapsules and the low thermal capacities of microencapsulated PCMs are the main problems that have been observed [2]. The current challenge is to find a suitable PCM that can be safe, thermally effective and at the same time not adversely effect the durability of a building. PCMs may be in microcapsulated form to meet these challenges. The most common PCM studied previously is paraffin, be it in bulk or microencapsulated. Leakage of paraffin from porous structures, the breaking of microcapsules and the low thermal capacities of microencapsulated PCMs are the main problems that have been observed [2. Paraffin is a fossil fuel derivative; thus, it is unsustainable. This study focuses on bio-based fatty acid mixtures as PCMs. We developed microcapsules of fatty acid mixtures that were tried in concrete mixes. Our design approach involved the following steps: determining and characterizing PCMs with suitable thermal properties; developing a method to synthesize microencapsulated PCMs; and finally incorporate these materials in buildings for improving thermal comfort and energy conservation. Please click Additional Files below to see the full abstract

Preparation and exhaustive characterization of paraffin or palmitic acid microcapsules as novel phase change material

In this study, two different types of Phase Change Materials (PCM) suitable for Thermal Energy Storage (TES) applications were used as a core material in a microencapsulation process. The wall material for these microencapsulated PCM (MPCM) was Poly(styrene-co-ethylacrylate) (PScEA). Microcapsules were prepared using an emulsion co-polymerization technique. The prepared MPCM were characterized as follows: morphology, shape and size were analyzed by Scanning Electron Microscopy (SEM) and Particle Size Distribution (PSD). Besides, Fourier Transformed Infrared spectroscopy (FT-IR) was used to perform the chemical characterization of the shell microcapsules. Moreover, thermophysical properties were analyzed by Differential Scanning Calorimetry (DSC) for the two PCM in usage (paraffin 42-44 and palmitic acid) meanwhile the thermal stability was evaluated by Thermogravimetrical Analysis (TGA). Mechanical characterization of the prepared microcapsules was performed by using the Atomic Force Microscopy (AFM) as indentor. Experiments were performed at two different temperatures 25 °C and 70 °C, and two parameters were evaluated: the Young's modulus on a punctual area and the vertical force required to plastically deform the MPCM. At the light of the results, it can be considered that these synthesized MPCM were successfully prepared being able to be used in a TES system

Microencapsulation of phase change material with poly (ethylacrylate) shell for thermal energy storage

WOS: 000344789100011Microcapsules containing caprylic acid and polyethylacrylate shells were prepared using an emulsion polymerization technique for thermal energy storage applications. Ethylene glycol dimethacrylate was used as a crosslinking agent. The influence of the crosslinking agent concentration on the phase change properties of microcapsules was examined. The caprylic acid microcapsules (MicroPCMs) were analyzed by Fourier transform infrared spectroscopy, thermal gravimetric analysis, scanning electron microscopy, and differential scanning calorimetry. The results showed that microcapsules were synthesized successfully and that the best shell material:crosslinking agent concentration ratio was 1:0.2. The melting and freezing temperatures were measured through differential scanning calorimetry analysis and found to be 13.3 and 7.1 degrees C, respectively. The melting and crystallization heats were determined to be 77.3 and -77.0kJ/kg, and the mean particle diameter was 0.64m. The thermal cycling tests of the microcapsules were performed for 400 heating/cooling cycles, and the results indicate that the synthesized microcapsules have good thermal reliabilities. Air stability test proved that the thermal properties and physical form of microcapsules were not affected by air. We recommend the prepared thermal, air, and chemically stable caprylic acid microcapsules for thermal energy storage applications as novel microPCM with latent heat storage capacities and properties. Copyright (c) 2014 John Wiley & Sons, Ltd.Scientific & Technical Research Council of Turkey (TUBITAK) [TUBITAK 111M614]The author would like to thank The Scientific & Technical Research Council of Turkey (TUBITAK) (The Project Code: TUBITAK 111M614) for their financial support for this study. The author would also like to thank Murat Unal and Suleyman Konuklu for their technical help and support for this study. Finally, the author would like to extend special thanks to the editor and the anonymous reviewers for their constructive comments and suggestions in improving the quality of this paper

Mikrokapsüllenmiş faz değiştiren maddelerde termal enerji depolama ile binalarda enerji tasarrufu

TEZ6673Tez (Doktora) -- Çukurova Üniversitesi, Adana, 2008.Kaynakça (s.156-160) var.xvi, 172 s. : rnk.res. ; 29 cm.Dependence on foreign energy resources for energy production and consumption and adverse environmental effects have made energy efficiency and conservation more important than ever. Many heating and cooling applications benefit from using thermal energy storage in phase change materials (PCM). Isothermal nature and high volumetric capacity of PCM's make them favourable. Challenge in PCM utilization is finding the optimum combination of appropriate melting point, thermal properties and encapsulation technique. For PCM microencapsulation the ultimate aim is not only to make PCM easier and safer to handle but also improve its thermal properties. In this study, thermal energy storage in microencapsulated PCMs was used to decrease heating and cooling load of a test building in Adana, Turkey...Enerji üretimi ve kullanımında yabancı kaynaklara bagımlılık ve çevre üzerindeki olumsuz etkiler enerji verimliligi ve tasarrufu konularını öne çıkarmıstır. Isıtma ve sogutma uygulamalarının verimliliginin arttırılmasında faz degistiren maddelerde (Phase changing materials-PCM) termal enerji depolamadan yararlanılmaktadır. PCM'lerin yüksek hacimsel depolama ve izotermal davranısları tercih edilmelerindeki en önemli nedenlerdir. PCM kullanımında en uygun erime noktası, termal özellik ve kapsülleme yöntemi bilesimini bulmak gerekmektedir. PCM mikrokapsüllenmesindeki esas hedef, maddenin kapsül içinde hapsolarak faz degisiminin kapsül içinde gerçeklesmesidir. Böylece, PCM'in kullanımı kolaylasırken ısı transferi açısından daha elverisli bir ortam olusmaktadır. Bu çalısmada mikrokapsüllenmis faz degistiren maddeler, Adana ilindeki bir test odasının ısıtma sogutma yükünü azaltmak amacı ile kullanılmıstır.Bu çalışma Ç.Ü. Bilimsel Araştırma Projeleri Birimi Tarafından Desteklenmiştir. Proje No:FEF2005D17 - 2005K120320

Preparation and characterization of sepiolite-based phase change material nanocomposites for thermal energy storage

WOS: 000382794900058This paper is one of the first study about the preparation and characterization of sepiolite-based phase change material nanocomposites for thermal energy storage applications. Sepiolite is an important natural fibrous raw material. Nanoscale fibrous tubular structure of sepiolite becomes important in nanocomposite preparation. In this study, sepiolite/paraffin and sepiolite/decanoic acid nanocomposites were manufactured by the direct impregnation method. By the preparation of nanocomposites, PCM move in tubular channels of sepiolite, phase changing occurs in these tubes and surface area increases like as in microencapsulation. The structure and properties of nanocomposites PCMs (CPCM) have been characterized via scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). The SEM results prove the successful preparation of phase change material/sepiolite nanocomposites and point out that the fibers of sepiolite is modified with phase change materials in the nanocomposite. The phase change enthalpies of melting and freezing were about 62.08 J/g and 62.05 J/g for sepiolite/paraffin nanocomposites and 35.69 J/g and -34.55 J/g for sepiolite/decanoic acid nanocomposites, respectively. The results show that PCM/sepiolite nanocomposites were prepared successfully and their properties are very suitable for thermal energy storage applications. (C) 2016 Elsevier Ltd. All rights reserved.Scientific & Technical Research Council of Turkey (TUBITAK) [TUBITAK 115M525]We would like to thank The Scientific & Technical Research Council of Turkey (TUBITAK) (The Project Code: TUBITAK 115M525) for financial support for this study

The Preparation and Characterization of Chitosan-Gelatin Microcapsules and Microcomposites with Fatty Acids as Thermal Energy Storage Materials

WOS: 000354740300007After cellulose, chitosan is the second-most-abundant natural resource and can be used as shell material during microencapsulation. In this study, chitosan-gelatin (CG) microcapsules and microcomposites containing either caprylic or decanoic acid were prepared according to the complex coacervation method and cross-linked by glutaraldehyde. To study the influence of the glutaraldehyde mass ratio upon encapsulation, as well as both the physical and thermal properties of the resulting microcapsules, the properties of microencapsulated phase-change materials (microPCMs) were analyzed by using scanning electron microscopy, differential scanning calorimetry, and Fourier transform infrared spectroscopy. Results show the successful synthesis of microPCMs and melting temperatures of approximately 11.5 and 24.2 degrees C with latent heat storage capacities of 79 and 73Jg(-1) for microPCMs containing caprylic acid and those containing decanoic acid, respectively.Scientific and Technological Research Council of Turkey (TUBITAK) [111M614]The authors thank the Scientific and Technological Research Council of Turkey (TUBITAK) (project code: 111M614) for its financial support of this study

Microencapsulation of a fatty acid with Poly (melamine-urea-formaldehyde)

WOS: 000334897700039The main purpose of this study is to obtain leakage-free, thermally stable decanoic acid microcapsules (microPCMs) for thermal energy storage applications. Decanoic acid (capric acid) is an environmentally friendly fatty acid since it is obtained from vegetable and animal oils. MicroPCMs were prepared with different capsule wall materials via a one-step in situ polymerization technique. The properties of microencapsulated PCMs have been analyzed by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermal gravimetric analyzer (TGA), Fourier transform infrared (FTIR) spectra analysis and particle size analyzer. The microPCMs prepared using Poly(urea-formaldehyde) (PUF) exhibit higher heat capacities and the microPCMs prepared using Poly(melamine-formaldehyde) (PMF) exhibit higher thermal stabilities. In order to obtain microPCMs with better properties such as suitable latent heat and better heat resistance at high temperatures, we microencapsulated decanoic acid with Poly (melamine-urea-formaldehyde) (PMUF). Furthermore, the effects of surfactants on microPCMs with PMUF were investigated by SEM, a particle size analyzer, DSC, and TGA. The results show that the binary surfactant system was a suitable emulsifier for this process. We determined that the melting temperature was close to 33 degrees C, the latent heat storage capacity was about 88 J/g, and the mean particle diameter was 0.28 mu m for microPCMs with PMUF. We recommend decanoic acid microencapsulated with PMUF for thermally stable and leakage-free applications above 95 degrees C. (C) 2014 Elsevier Ltd. All rights reserved.Scientific & Technical Research Council of Turkey (TUBITAK) [TUBITAK 111M614]; Research Projects Unit of Nigde University [FEB2011/18]We would like to thank The Scientific & Technical Research Council of Turkey (TUBITAK) (The Project Code: TUBITAK 111M614) and Research Projects Unit of Nigde University (The Project Code: FEB2011/18) for their financial support for this study. We also would like to thank the editorial board and the anonymous reviewers for their helpful and constructive comments and suggestions thatgreatly contributed to improve the quality of the paper

Synthesis and properties of microencapsulated phase change materials for thermal energy storage materials

15th International Scientific Conference on Renewable Energy and Innovative Technologies -- JUN 10-11, 2016 -- Tech Coll Smolyan, Smolyan, BULGARIAWOS: 000392370100029This work presents and discusses the microencapsulation of pentadecane in polystyrene shell as thermal energy storage materials. The emulsion polymerisation method was used for the microencapsulation process. Styrene (S) was used as monomer to obtain polystyrene (PS) and ethylene glycol dimethacrylate was used as crosslinking agents. The influence of the core: shell mass ratio on the encapsulation process and the physical properties of the resulting microcapsules have been studied. The surface morphologies of the microencapsulated phase change materials (microPCMs) were studied by scanning electron microscopy (SEM) and the thermal properties of the MicroPCMs were investigated by differential scanning calorimetry (DSC). SEM photographs showed that these microPCMs have relatively spherical profiles with diameter ranging from 10 to 80 mu m. It was determined that, the phase change enthalpies of melting and freezing were about 83.2 J/g and 81.8 J/g, respectively. The results show that pentadecane was microencapsulated successfully and its properties very suitable for thermal energy storage applicationsScientific & Technical Research Council of Turkey (TUBITAK) [TUBITAK 111M614]The authors would like to thank The Scientific & Technical Research Council of Turkey (TUBITAK) (The Project Code: TUBITAK 111M614) for their financial support for this study

Easy and industrially applicable impregnation process for preparation of diatomite-based phase change material nanocomposites for thermal energy storage

WOS: 000365053200076The high porosity, high oil and water absorption capacity and low density of diatomite make it ideal for industrial applications. The porous structure of diatomite protects phase change materials (PCMs) from environmental factors as a supporting matrix and phase changes occur in nanopores of diatomite. Previous research on diatomite/PCMs composites aimed optimal composite preparation but many methods were feasible only in laboratory scale. In large scale industrial fabrication, easy, continuous and steady state methods are need to be performed. The main purpose of this study was to prepare leakagefree, thermally stable nanocomposite PCMs (nanoCPCMs) by an easy, continuous and steady state method for high temperature thermal energy storage applications. A series of nanoCPCMs with different paraffin:diatomite mass ratios were prepared. The properties of nanoCPCMs have been characterized via scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (MR). The leak (exudation) test was performed on prepared composites at higher temperatures (95 degrees C) in comparison with literature. As the optimum composite for thermal energy storage applications, thermal reliability of nanoCPCM was evaluated after 400 cycles of melting and freezing. NanoCPCM melted at 36.55 degrees C with latent heat of 53.1 J/g. (C) 2015 Elsevier Ltd. All rights reserved.Scientific & Technical Research Council of Turkey (TUBITAK) [TUBITAK 115M525]We would like to thank The Scientific & Technical Research Council of Turkey (TUBITAK) (The Project Code: TUBITAK 115M525) for partly financial support for this study. The authors would like to extend special thanks to the editor and the anonymous reviewers for their constructive comments and suggestions in improving the quality of this paper