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

Thermal energy storage in phase change materials for greenhouse applications.

TEZ8056Tez (Yüksek Lisans) -- Çukurova Üniversitesi, Adana, 2010.Kaynakça (s. 73-76) var.xi, 77 s. : res. (bzs. rnk.), çizelge ; 29 cm.Root zone heating with thermal energy storage in phase change materials (PCM) to keep plant temperature at the optimum levels has been investigated for soilless agriculture greenhouses without heating system. With this objective, a system for night time heating of the substrate at Çukurova University Horticulture Department research greenhouse, where soilless agriculture is carried out, was developed. The candidate PCMs appropriate for night development temperatures of the plants to be grown were determined as %40 oleic acid-%60 decanoic acid mixture and ?-oleic acid. Measurements at two different periods of November and March-April were carried out with the system developed. In the November period, when zucchinis were grown, %40 oleic acid-%60 decanoic acid mixture was used as the PCM and temperature increase in the PCM channel with respect to control was observed 1,9°C - 1,2°C. Between 6 March - 8 April, when pepper was grown, both PCMs were tested and the mixture has been more effective then the oleic acid and the maximum temperature differences attained with respect to the control were 2,4°C and 2,1°C. Energy calculations revealed that even though the mass of the mixture was about half of the oleic acid, the storage efficiency of the mixture was higher due to the fact that phase change temperature was more suitable for the night time temperature during the measurement periods.Bu çalışmada herhangi bir ısıtma sisteminin kullanılmadığı seralarda bitkilerin gelişim sıcaklıklarını korumak için faz değiştiren maddede(FDM) termal enerji depolamayla topraksız tarım uygulamalarında kök bölgesinin ısıtılması araştırılmıştır. Bu amaçla Çukurova Üniversitesi Bahçe Bitkileri bölümünün topraksız tarımın yapıldığı araştırma serasında gece kültür ortamının ısıtılması için bir sistem geliştirilmiştir. Yetiştirilecek bitkilerin gece gelişim sıcaklıklarına uygun aralıkta FDM'lere aday olarak %40 oleik asit-%60 dekanoik asit karışımı ve ?-oleik asit belirlenmiştir. Geliştirilen sistem ile Kasım ve Mart-Nisan aylarında iki ayrı periyotta ölçümler alınmıştır. Kabak üretiminin yapıldığı Kasım ayında alınan ölçümlerde sadece %40 oleik asit-%60 dekanoik asit karışımı kullanılmış, kontrole göre FDM'li kanalette 1,9°C ile 1,2°C arasında değişen sıcaklık artışları elde edilmiştir. Biber üretiminin yapıldığı 6 Mart-8 Nisan tarihleri arasında her iki FDM kullanılmış ve karışımın oleik asitten daha etkili olduğu, kontrole gore 2,4°C ve 2,1°C'lik farklar elde edildiği görülmüştür. Enerji hesaplamalarının sonuçlarına göre FDM olarak kullanılan karışımın miktarı, oleik asitin yaklaşık yarısı olmasına rağmen faz değiştirme sıcaklığının ölçüm yapılan peryotta gece hava sıcaklıklarına daha uygun olması nedeniyle depolamanın etkinliğinin daha yüksek olduğu belirlenmiştir.Bu çalışma Ç.Ü. Bilimsel Araştırma Projeleri Birimi tarafından desteklenmiştir. Proje No: FEF2009YL52

Robust microencapsulated phase change materials in concrete mixes for sustainable buildings

WOS: 000394784600009For 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 (C) 2016 John Wiley & Sons, Ltd.TUBITAK [111M557]; Cukurova University under BAP project [FDK-2015-3277, FDK-2015-3278]; Kambeton CompanyThe authors would like to acknowledge the support provided by TUBITAK under the project no. 111M557, Cukurova University under BAP project nos. FDK-2015-3277 and FDK-2015-3278, and Kambeton Company

Thermal enhancement of concrete by adding bio-based fatty acids as phase change materials

WOS: 000363346100015An effective way to enhance the thermal storage capacity of buildings is to incorporate phase change materials (PCM) into building materials. Fatty acids are derivatives of materials readily found in nature and labeled as bio-based. In this study, we tested binary mixtures of capric acid (CA), myristic acid (MA), lauric acid (LA), and palmitic acid (PA) as candidate materials for building applications. The melting points of such fatty acid mixtures may further be adjusted, to agree with human comfort zone temperatures by regulating their compositions. We developed two binary mixtures of CA-LA and CA-MA as candidate PCMs for building applications. Thermal storage capacities were measured to be 109.0-155.4 J/g with a differential scanning calorimeter. Thermal cycle tests showed that both PCMs are thermally and chemically stable. Durabilities of PCM mixtures determined by the thermal gravimetric analysis indicated that degradation started at 120 degrees C. The compressive strengths of 1 wt.% PCM added to concrete mixtures were reduced by 12%, yet stayed within the desired limits for C35/45 concretes. However, when PCM contents were increased to 2 wt.%, compression strengths were reduced further, to be within the limits of C30/37 concretes. Both PCMs were suitable for self-compacting concrete mixtures used in buildings. (C) 2015 Elsevier B.V. All rights reserved.TUBITAK [111M557]; COST Action [TU0802]; Cukurova University BAP [FDK-2015-3278]; Kambeton Co.The authors would like to acknowledge the support provided by TUBITAK under the Project No. 111M557, COST Action TU0802, Cukurova University BAP Project No. FDK-2015-3278 and Kambeton Co

Unilateral Cerebellar Hypoplasia with Different Clinical Features

Unilateral cerebellar hypoplasia (UCH) is a rare pathological condition characterized by the loss of volume in cerebellar hemispheres ranging from mild asymptomatic to severe symptomatic cases. As the designation of UCH remains problematic, the underlying etiopathogenesis also lacks explanation. We investigated the patients admitted to Departments of Child Neurology, Neurology, and Genetics between the years 1992 and 2010 and detected 12 patients with unilateral cerebellar volume loss, with the exclusion of all other cerebellar pathologies. The ages of patients ranged between 6 months to 55 years. Five patients had a delay in developmental milestones, and one of these was diagnosed with neurofibromatosis type 1. Two patients had epileptic seizures, one patient had peripheral facial paralysis as a component of Moebius syndrome, and four patients were incidentally diagnosed during etiological work-up for headache. The clinical outcomes of patients varied from healthy subjects to marked developmental impairment. Radiologically, five patients had severe disproportionate UCH, six had moderate disproportionate, and one had mild proportionate UCH. Cerebellar peduncles were affected in all, and vermis was partly hypoplastic in eight patients. Brainstem was involved in four patients, and seven patients showed involvement of white matter and/or corpus callosum. Imaging features supported that patients with severe disproportionate UCH also displayed additional cerebral and commissural changes, which were related to ischemic or vascular injuries, implying a prenatally acquired disruption. In the presence of such a wide spectrum of clinical and radiological features, a prenatally acquired lesion and, thus, a disruption seem to be more explanatory rather than a primary developmental process or malformation in the etiopathogenesis of unilateral cerebellar hypoplasia