Yazar "Bayram, Muhammed" seçeneğine göre listele

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    3D-printed polylactic acid-microencapsulated phase change material composites for building thermal management
    (Pergamon-Elsevier Science Ltd, 2024) Bayram, Muhammed; Ustaoglu, Abid; Kursuncu, Bilal; Hekimoglu, Gokhan; Sari, Ahmet; Ugur, Latif Onur; Subasi, Serkan
    The integration of phase change materials (PCM) into architectural elements is an emerging strategy to enhance thermal energy storage in modern buildings. This research examines 3D-printed polylactic acid structures incorporated with microencapsulated PCM, targeting a more efficient thermoregulation in foundational architectural sections such as walls, floors, and ceilings. Through rigorous evaluations, the polylactic acid-PCM composite revealed promising thermoregulatory properties. Notably, latent heat values stood at 198.4 J/g for melting and 197.9 J/g for freezing. Real-world experiments demonstrated a distinct advantage, maintaining temperatures 3.2 degrees C-3.3 degrees C higher than standard polylactic acid at night and exhibiting a cooler range of 10.4 degrees C-13.3 degrees C during daylight. Within specific geographical contexts, like the Mediterranean and Aegean Seas coastline, 0.026 m thick polylactic acid-PCM panels stood out, registering 100 % energy savings. The findings consistently showed that an increase in panel thickness correlated with a decrease in building heating needs. Further analysis explored the carbon emissions landscape. Coal, when utilized with 0.05 m-thick polylactic acidPCM panels, was identified as particularly effective, yielding a reduction of 34 kg/m2 in annual CO2 emissions. Collectively, the findings underscore the transformative potential of polylactic acid-PCM composites, positioning them as pivotal tools for advancing architectural energy efficiency and fostering sustainable building innovations.
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    Effect of carbon nanotube and microencapsulated phase change material utilization on the thermal energy storage performance in UV cured (photoinitiated) unsaturated polyester composites
    (Elsevier, 2023) Subaşı, Azime; Subaşı, Serkan; Bayram, Muhammed; Sarı, Ahmet; Hekimoğlu, Gökhan; Ustaoğlu, Abid; Gencel, Osman
    The utilization of phase change materials in the synthesis of polyester is an economically viable approach for the production of polymer composites with remarkable thermal and mechanical characteristics, thereby facilitating thermal energy savings. This study manufactured a series of unsaturated polyester resin (UPR)/carbon nanotubes (CNT)/MPCM composites via mechanical mixing and ultrasonication processes and the produced composites were cured with ultraviolet (UV) curing technology. The unsaturated polyester resin was utilized as a support matrix, and to improve the thermal conductivity of MPCM-UPR composites, CNT were introduced into the matrix. This paper discusses the effect of CNT and MPCM on the mechanical, thermal, and thermal regulative performance of polyester composites. A 10 wt% incorporation of MPCM led to an almost 77 % and 15 % drop at Charpy impact strength and Shore D hardness values of reference UPR, respectively. Similarly, the introduction of substitution of 0.005 wt% of CNT reduced the impact strength of the specimen with 10 % MPCM by 31 %, while it increased the Shore D hardness by almost 5 %. Although the thermal conductivity of reference resin was reduced by 15 % with a 10 % addition of MPCM, CNT content increased the thermal conductivity values by almost 20 % regardless of MPCM concentration. The onset melting and freezing temperatures of MPCM were found to be 21.71 and 22.74 degrees C, respectively; while for the composites with and without CNT, this value ranged between 20.70 and 22.39 degrees C and 22.45-22.90 degrees C, respectively. Thermoregulation test results indicate that MPCM improved the thermal energy storage capacity of composites. The results of this research will be of great sig-nificance in order to gain a more comprehensive understanding of the thermal properties of polyesters with MPCM/CNT, thus allowing for the utilization of this material as a latent heat thermal energy storage system for energy conservation.
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    Light transmitting glass fiber reinforced cementitious composite containing microencapsulated phase change material for thermal energy saving
    (Elsevier Sci Ltd, 2022) Gencel, Osman; Sarı, Ahmet; Subaşı, Serkan; Bayram, Muhammed; Danish, Aamar; Maraşlı, Muhammed; Hekimoğlu, Gökhan
    The energy utilization for artificial lighting, cooling, heating, and air conditioning in buildings results in the release of greenhouse gases and causes climate crises. In this regard, a novel light-transmitting cementitious composite (LTCC) was developed by substituting microencapsulated phase change material (MPCM) to reduce the building energy utilization via transmitted light through the composite and improve the solar thermal energy efficiency. The cementitious matrix is produced with cement, kaolin, silica sand, water, superplasticizer, adhe-sive polymer, glass fiber, different ratios of MPCM, and plastic optical grids to let inward sunlight transmittance. The current study thoroughly investigates the characteristics of light-transmitting composite, including MPCMs, via physico-mechanical, chemical, microstructural, thermal, light transmittance and solar thermoregulation tests. The thermal conductivity of the composite with 0 wt% MPCM decreased from 1.09 W/mK to 0.96 W/mK with 15 wt% MPCM addition. Incorporating 10 wt% of MPCM reduced the 28 days-compressive strength of specimens by almost 28 % due to the lower strength and density of microcapsules, as well as the voids formed by damaged MPCMs. On the other hand, the incorporation of MPCM did not dramatically affect the flexural strength of the cementitious composite. DSC analysis results revealed that the composite containing 15 wt% MPCM shows a latent heat of fusion of 14.6 J/g with a melting point of 17.65 degrees C. FTIR analysis disclosed that MPCM maintains its chemical structure in the composite. Composite slabs exhibited up to 12.4 % artificial light transmittance, which would translate to a considerable increase in the lighting efficiency of commercial and residential buildings. Thermoregulation performance test under ambient conditions indicates that the specimen containing 15 wt% MPCM can provide a cooler room temperature for 6.5 h when the room or surface temperatures increase above 21-23 degrees C, and a warmer room when the temperature decreases below these temperatures. The findings of the current study can be applied to enhance thermal energy saving and artificial lighting efficiency in buildings that inspire the design of environment-friendly constructions.
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    Microencapsulated phase change material incorporated light transmitting gypsum composite for thermal energy saving in buildings
    (Elsevier, 2023) Gencel, Osman; Bayram, Muhammed; Subasi, Serkan; Hekimoglu, Gokhan; Sari, Ahmet; Ustaoglu, Abid; Marasli, Muhammed
    The increased energy consumption for specific applications, including heating, cooling, air conditioning and lighting of residential and commercial buildings accelerate the research efforts concentrated on developing thermal energy storage capacity of buildings materials in recent years. Likewise, the development of light-transmitting building elements is a novel energy-saving technique that enhances lighting efficiency in build-ings. In light of these, the current study seeks to design an untried microencapsulated phase change material (MPCM) integrated glass fiber reinforced gypsum composite with sufficient light-transmitting properties and thermal energy storage capacity. In this research, a multi-scale investigation of light-transmitting gypsum composite was conducted experimentally with physical, mechanical, chemical, microstructural, thermal, light transmittance and solar thermoregulation tests. The gypsum composite is formed from alpha-gypsum, water, polymer admixture, alkali-resistant glass fiber (AR-GF), several concentrations of MPCM, and plastic optical grids to allow light to transmit through the board. Although higher fractions of MPCM yielded an apparent decrease in me-chanical strength test results, 5 wt% introduction of MPCM to the reference matrix reduced the compressive and flexural strength of specimens by 1 and 8 %, respectively. The results verified a reduction trend in thermal conductivity of composites with MPCM loading. DSC investigations revealed that the melting temperature and the regarding latent heat storage capacity of gypsum composite with 15 wt% of MCPM are 17.76 degrees C and 19.2 J/g, respectively. Light-transmitting gypsum composites showed up to similar to 10 % light transmittance, that can greatly increase the efficiency of lighting in buildings. The produced gypsum composites with MPCM kept the test room cooler during the highest temperature, while it provided a warmer room during the nighttime for an extended time. The study's findings are applicable to increase thermal comfort by reducing the significant temperature variations in buildings and improving artificial lighting efficiency, encouraging the design of sustainable building applications.