Whale ‘blubber’ as bio-inspired phase change material

In nature, all living things have various features to survive. For example, marine mammals have an adipose tissue system that protects them from harsh conditions in their environment. This tissue also known as “blubber” provides various features to marine mammals. Buoyancy, insulation, protection and energy storage are among the tasks of this tissue. Thermal energy storage systems are regarded as key to sustainable use of renewables to meet increasing global energy demand. Phase Change Materials (PCM) with thermal energy storage properties are commonly used in a wide variety of applications based on melting-freezing principle. PCMs can be inorganic or organics. Fatty acids are examples of organic PCMs. Please download the PDF file for the full content

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

CO2 mitigation accounting for Thermal Energy Storage (TES) case studies

According to the IPCC, societies can respond to climate changes by adapting to its impacts and by mitigation, that is, by reducing GHG emissions. No single technology can provide all of the mitigation potential in any sector, but many technologies have been acknowledged in being able to contribute to such potential. Among the technologies that can contribute in such potential, Thermal Energy Storage (TES) is not included explicitly, but implicitly as part of technologies such as energy supply, buildings, and industry. To enable a more detailed assessment of the CO2 mitigation potential of TES across many sectors, the group Annex 25 ''Surplus heat management using advanced TES for CO2 mitigation'' of the Energy Conservation through Energy Storage Implementing Agreement (ECES IA) of the International Energy Agency (AEI) present in this article the CO2 mitigation potential of different case studies with integrated TES. This potential is shown using operational and embodied CO2 parameters. Results are difficult to compare since TES is always designed in relation to its application, and each technology impacts the energy system as a whole to different extents. The applications analyzed for operational CO2 are refrigeration, solar power plants, mobile heat storage in industrial waste heat recovery, passive systems in buildings, ATES for a supermarket, greenhouse applications, and dishwasher with zeolite in Germany. The paper shows that the reason for mitigation is different in each application, from energy savings to larger solar share or lowering energy consumption from appliances. The mitigation potential dues to integrated TES is quantified in kg/MW h energy produced or heat delivered. Embodied CO2 in two TES case studies is presented, buildings and solar power plants

Unconventional experimental technologies used for phase change materials (PCM) characterization: part2 morphological and structural characterization, physico-chemical stability and mechanical properties

Due to the high interest of appropriate characterization of PCM and hybrid PCM composites, different research centres and universities are using several material characterization techniques not commonly used with PCM, to study the structure and morphology of these materials. Likewise, physico-chemical stability is a crucial parameter for the performance of latent storage materials during time and its evaluation has been done by using molecular spectroscopy, chemiluminiscence or calorimetric tests. Atomic force microscopy and nanoindentation are also reported to characterize hybrid PCM composites

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

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

Nanoencapsulation of n-alkanes with poly(styrene-co-ethylacrylate) shells for thermal energy storage

WOS: 000356122500030In this work, we synthesized a series of four nanocapsules containing n-alkanes (CnH2n+2), namely tetradecane, pentadecane, hexadecane, and heptadecane, in poly(styrene-co-ethylacrylate) using an emulsion copolymerization method. The nanocapsules were characterized according to their geometric profiles, phase transition temperatures, phase transition heats, mean particle sizes, and chemical stabilities by means of scanning electron microscopy, differential scanning calorimetry, thermal gravimetric analysis and Fourier transform infrared spectroscopy. Furthermore, we also focused on the effect of the core/shell mass ratio on the phase change properties of the nanocapsules. We found that microcapsules were synthesized successfully and that the best core/shell mass ratio was 3:1 for this study. These results indicate that encapsulated n-alkanes with poly(styrene-co-ethylacrylate) have an excellent potential for energy storage. (C) 2014 Elsevier Ltd. All rights reserved.Scientic & Technical Research Council of Turkey (TUBITAK) [TUBITAK 111M614]We would like to thank The Scientic & Technical Research Council of Turkey (TUBITAK) (The Project Code: TUBITAK 111M614) for their financial support for this study. And also we would like to thank Mr. Suleyman Konuklu for his technical support for this study. Finally, we 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

Microencapsulation of caprylic acid with different wall materials as phase change material for thermal energy storage

WOS: 000329595800012In this study, caprylic acid (octanoic acid) suitable for thermal energy storage applications was microencapsulated with different wall materials, including urea-formaldehyde resin, melamine-formaldehyde resin, urea+melamine-formaldehyde resin. Microcapsules were prepared using coacervation method. Hardening process of microencapsulated phase change material (PCM) was done with formaldehyde. The morphology and particle sizes of microencapsulated PCM were analyzed by scanning electron microscopy, (SEM). The latent heat storage capacities of caprylic acid and microencapsulated caprylic acid were determined with differential scanning calorimetry (DSC). The chemical characterization of microcapsules was determined by Fourier transformed infrared (FTIR) spectroscopy. It is concluded that urea-formaldehyde resin was the best capsule wall material for caprylic acid. Based on all results, it can be considered that the microcapsules were synthesized successfully and that, the phase change enthalpies of melting and freezing were about 93.9 J/g and 106.1 J/g, respectively, the particle diameter was 200 nm-1.5 mu m. (C) 2013 Elsevier B.V. All rights reserved.Scientific & Technical Research Council of Turkey (TUBITAK) [TUBITAK 111M614]; Research Projects Unit of Nigde University [FEB2011118]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: FEB2011118) for their financial support for this study. And also we would like to thank Mr. Suleyman Konuklu for his technical support for this study

Review on sensible thermal energy storage for industrial solar applications and sustainability aspects

Industry is one of the leading energy consumers with a global share of 37%. Fossil fuels are used to meet more then 80% of this demand. The sun's heat can be exploited in most industrial processes to replace fossil fuels. Integration of a thermal energy storage system is a requisite for sustainability in solar heat for industries. Currently there are only 741 solar heat industrial plants operating with an overall collector area of 662,648 m2 (567 MWth) that cover very small share of total global capacity. This is only the tip of the iceberg- there is a huge potential that is eager to be exploited. The challenges of increasing cost-effective solar heat applications are development of thermal energy storage systems and materials that can deliver this energy at feasible economic value. Sensible thermal energy storage, which is the oldest and most developed, has recently gained interest due to demand for increased sustainability in energy use. This paper attempts to review these latest trends in sensible thermal energy storage systems and materials that are used in solar industrial applications with a special focus on sustainability. The aim is to provide information for further research and development that shall make solar heat a cost-effective method to meet the increasing energy demand of the industrial sector