Yazar "Guler, Onur" seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • Küçük Resim Yok
    Öğe
    Characterisation and energy storage performance of 3D printed-photocurable resin/microencapsulated phase change material composite
    (Elsevier, 2024) Er, Yusuf; Guler, Onur; Ustaoglu, Abid; Hekimoglu, Gokhan; Sari, Ahmet; Subasi, Serkan; Gencel, Osman
    The 3D fabrication of microencapsulated phase change material (MEPCM) doped resin polymer composites enables the creation of complex shapes and customized designs, opening doors for many applications in fields. This investigation fabricated a range of resin/MEPCM (20 %, 30 %, and 40 % by volume) composites using a mechanical mixing technique. This study investigates how the addition of MEPCM impacts resin matrix composite's mechanical strength, latent heat storage characteristics, and ability to regulate temperature effectively. With a 40 % MEPCM additive ratio, a pure resin porosity value of approximately 0.4 % increased to around 17 %. Thanks to the production of homogeneously dispersed MEPCM added resins with production with stereolithography (SLA), 40 % MEPCM additive enabled characteristic FTIR peaks of both MEPCM and resin to appear and, melting and solidification enthalpy values reached 87.15 j/g and 86.25 j/g, respectively. MEPCM addition enhanced the thermoregulatory properties of resin by absorbing or releasing heat during temperature fluctuations. On hotter days, 8 mm-thick composites create temperature differences exceeding 11 C, while this difference exceeds 6 C in the room center case. The produced 3D printed MEPCM/resin composite can be a potential material to effectively regulate the temperature of electronic devices, food packets, building materials, and electronic devices and automotive components.
  • Küçük Resim Yok
    Öğe
    Enhancing sustainability with waste hemp-shive and phase change material: Novel gypsum-based composites with advanced thermal energy storage properties
    (Elsevier Sci Ltd, 2024) Gencel, Osman; Guler, Onur; Ustaoglu, Abid; Erdogmus, Ertugrul; Sari, Ahmet; Hekimoglu, Gokhan; Boztoprak, Yalcin
    This study addresses the rising demand for sustainable construction by introducing composite materials from natural and renewable resources: gypsum, hemp, and phase change materials (PCMs). These materials cater to the growing preference for eco-friendly building solutions. Incorporating hemp enhances sustainability while integrating PCMs into the porous hemp structure ensures adequate thermal energy storage and release without leakage. Firstly, the agricultural waste hemp shives and lauryl alcohol (LA) PCM were mixed to create shapestabilized hemp/PCM composites. The highest PCM ratio was determined in shape-stabilized composites exhibiting non-leakage properties, which was 45 wt %. These composites were then incorporated into gypsum materials at loadings of 7.5 %, 15 %, 22.5 %, and 35 wt % to produce the final composites. Morphological, thermal, and chemical characteristics of shape-stabilized composites were examined using SEM, TGA, and DSC, while the solar thermoregulation tests assessed the gypsum matrix composites. The phase change temperature of PCM was determined as 20.24 degrees C with a melting enthalpy value of 224.4 J/g. The hemp/PCM shape-stabilized composites demonstrated an impressive melting enthalpy value of 100.2 J/g, with only a slight reduction to 99.5 J/g after 750 test cycles. When the ambient temperature exceeded 50 degrees C, the central temperature of the cabins containing PCM composites was found to be at least 4 degrees C cooler than those containing only gypsum. Conversely, when the ambient temperature dropped to around 20 degrees C, it was observed that the central temperature of the cabins with PCM composites was approximately 2 degrees C warmer than those with only gypsum. This study introduces a novel approach to creating environmentally friendly gypsum/hemp/PCM composites for thermal energy storage systems.
  • Küçük Resim Yok
    Öğe
    Production and assessment of UV-cured resin coated stearyl alcohol/ expanded graphite as novel shape-stable composite phase change material for thermal energy storage
    (Pergamon-Elsevier Science Ltd, 2024) Guler, Onur; Er, Yusuf; Hekimoglu, Gokhan; Ustaoglu, Abid; Sari, Ahmet; Subasi, Serkan; Marasli, Muhammed
    Expanded graphite -phase change materials (PCM) structures are reinforced to polymers with various methods to fabricate advanced thermal energy storage materials. However, these methods still suffer from processing time and product efficiency challenges. In this study, the UV-curing method was used to produce shape-stable EGPCM-reinforced resin composites with fast curing and low process temperature of the resin. The composite material, comprising UV -curable resin (30 %), stearyl alcohol (65 %), and Expanded graphite (5 %), was synthesized. This synthesis aimed to address the limitations of traditional PCMs, such as low thermal conductivity and leakage. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to characterize the materials ' phase change behavior and thermal stability. Scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) analyses were conducted to elucidate the microstructure and crystallinity of composite materials. The composites, exhibiting near-perfect impermeability with leakage as minimal as 0.89 %, not only enable the attainment of cooler environments by 2 - 3 degrees C under hot air conditions but also demonstrate exceptional thermal stability up to 207 degrees C, as evidenced by TGA results. Additionally, they offer a remarkable melting enthalpy value of 153.1 J/g. These composites, with their shape-retention ability during phase transitions and high thermal energy storage capacity, are a versatile and efficient option for sustainable energy management. This research contributes to the development of innovative materials for renewable energy integration and reducing carbon emissions.