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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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    Biocomposite foams consisting of microencapsulated phase change materials for enhanced climatic regulation with reduced carbon dioxide emissions in buildings
    (Elsevier Sci Ltd, 2024) Gencel, Osman; Aydogmus, Ercan; Guler, Onur; Ustaoglu, Abid; Sari, Ahmet; Hekimoglu, Gokhan; Subasi, Serkan
    Using polyurethane foam (PUF) matrix-based phase change material-enhanced composites is crucial for improving energy efficiency, enhancing thermal regulation, and reducing environmental impact in buildings. Integrating bio-components into PUF production and using these bio-composite foams (BPUFs) as the matrix offers environmentally friendly and structurally advanced solutions. Microencapsulated phase change material (MPCM) further enhances these foams, creating innovative, high-performance, eco-friendly composites for building applications. In this context, the biocomponent castor oil (CO) to be used in BPUF production has been modified with epoxy. BPUF-MPCM biocomposites with different compositions were produced using MPCM in the range of 0-90 wt% and modified castor oil (MCO) in the range of 0.75-7.50 wt% in BPUF production. The addition of 90 wt% MPCM content in BPUF-MPCM biocomposites has facilitated the attainment of a melting enthalpy value of 176.8 J/g (at 25.4 C-degrees) while providing a solidification enthalpy value of 175.7 J/g (at 20.8 C-degrees). The advancements in the microstructure of BPUF-MPCM composites contribute to physical improvements, such as a more homogeneous cell structure and enhancements in thermal transformation properties, thereby contributing to their thermoregulatory characteristics. BPUF-MPCM 90 wt% composites have achieved 100 % energy savings and zero CO2 emission values by varying material thicknesses across all climate conditions.
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    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.
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    Characteristics of cement-based thermo-concretes containing capric acid impregnated hemp for thermal energy storage and sound isolation in buildings
    (Pergamon-Elsevier Science Ltd, 2025) Gencel, Osman; Guler, Onur; Ustaoglu, Abid; Erdogmus, Ertugrul; Sari, Ahmet; Hekimoglu, Gokhan; Boztoprak, Yalcin
    Enhancing the lightweight structure, insulation, and thermal storage capacity of concrete is critical for energy efficiency and environmental impact reduction. The innovative application of using waste hemp shives as a phase change material (PCM) carrier in cementitious composites was performed in this study to enhance sustainable construction practices. Although previous studies have incorporated lightweight aggregates and PCMs, challenges such as PCM leakage and the reliance on synthetic materials have limited their effectiveness. This study utilized waste hemp shives as a natural porous support for capric acid (CA) PCM in diatomite-based lightweight concrete, offering an eco-friendly and leakage-resistant solution with improved thermal and acoustic performance. No leakage was observed in shape-stabilized hemp/CA composites with 45 wt% CA. The melting and solidification temperatures were determined as 30.6 degrees C and 28.7 degrees C, with corresponding enthalpy values of 80.9 and 80.8 J/g, respectively. Concrete composites containing hemp/PCM reduced indoor temperatures by up to 4 degrees C compared to control samples. Moreover, composites with 30 % hemp/PCM content achieved sound absorption coefficients up to 0.6 and transmission loss values exceeding 24 dB, demonstrating their dual functionality for thermal energy conservation and acoustic comfort in building applications.
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    Developing Wallpaper/Dodecyl alcohol composite phase change materials as new kind of wall covering elements for building interior thermoregulation
    (Elsevier, 2023) Gencel, Osman; Ustaoglu, Abid; Sari, Ahmet; Hekimoglu, Gokhan; Sutcu, Mucahit; Tozluoglu, Ayhan; Tutus, Ahmet
    This study introduces a novel wall-covering element consisting of wallpapers (WP) impregnated with Phase Change Material (PCM), with the aim of enhancing thermal properties and providing effective thermal regulation performance in interior spaces. The study conducts practical investigations into the thermal attributes of wall-papers (WPs) impregnated with Dodecyl alcohol (DDA) as the chosen PCM, culminating in a leakage-free WP/ DDA wall covering element. The process of impregnating involved applying liquid DDA to the back side of the WP using a manual coating apparatus. Four distinct DDA ratios, ranging from 0% to 20% by mass of WP, were applied. The chemical compatibility of the developed WP/DDA composite was explored using Fourier Infrared Spectroscopy (FTIR). The thermal energy storage (TES) properties were assessed through Differential Scanning Calorimeter (DSC) analysis, and the thermo-regulative performance of the WP/DDA composite was evaluated in laboratory-scale test rooms under real weather conditions. The DSCoutcomesexposed that melting temperature and latent heat capacity of WP/DDA were 21.78 degrees C and 26.9 J/g, respectively.The thermoregulation tests showed that the prepared WP/DDAsignificantly reduce interior room temperature fluctuation and can maintain indoor temperature longer in comfortable temperature ranges. The largest difference between the reference room and test room was observed to be about 2celcius. The room temperature was cooler for about 9 h 53 min during day times for the DDA case.The results designated that the developed WP/DDA composite could be evaluated as a promising new kind of building wall covering element for reducing the cooling load of room.
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    Effects of microencapsulated phase change material on physico-mechanical and thermoregulation performance of lightweight geopolymer concrete with zeolite and perlite
    (Elsevier, 2025) Oren, Osman Hulusi; Mandev, Emre; Kaya, Mehmet; Sari, Ahmet; Hekimoglu, Gokhan; Cikman, Ismail Umit; Subasi, Serkan
    This study examines impact of microencapsulated phase change material (MPCM) additives on physical and mechanical characteristics of geopolymers produced using natural zeolite and slaked lime. The binder composition consists of 90 % zeolite and 10 % slaked lime, activated with NaOH at a Na/binder ratio of 14 % by weight. Basalt-based sand and perlite were used as aggregates with a water/binder ratio of 0.60. MPCM was added in varying proportions of 8 %, 16 %, and 24 % relative to the binder weight. Samples were molded in dimensions of 50 x 50 x 50 mm and 200 x 200 x 20 mm, then cured at 95 degrees C for 24 h. Differential Scanning Calorimetry (DSC) outcomes presented that geopolymer composite with MPCM has a melting degree of 26.45 degrees C and a melting enthalpy of 17.8 J/g. Fourier Transform Infrared Spectroscopy (FTIR) results confirmed physical integration of MPCM into geopolymer structure. The study also evaluated compressive strength, ultrasound pulse velocity (UPV), dry unit weight, and microstructural properties using Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). Thermoregulation performance experiments demonstrated that the MPCMenhanced samples effectively moderated temperature fluctuations, maintaining lower temperatures for controlled heating and higher temperatures for natural cooling phases compared to the control sample. Thermal regulation capabilities of MPCM-infused geopolymers were evidenced by their property of absorbing and releasing heat, which is critical for energy-efficient building materials. Additionally, the durability and stability of the geopolymer matrix were enhanced by the uniform dispersion of MPCMs, which also improved the composite's mechanical performance. The successful integration of MPCMs highlights their potential in developing sustainable construction materials that contribute to energy savings and environmental conservation.
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    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.
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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.
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    Microencapsulated phase change material/wood fiber-starch composite as novel bio-based energy storage material for buildings
    (Elsevier, 2024) Ozturk, Guliz; Temiz, Ali; Hekimoglu, Gokhan; Aslan, Mustafa; Demirel, Gaye Kose; Erdeyer, Ozge Nur; Sari, Ahmet
    This work is aimed to produce a novel energy effective-composite material was prepared for building thermal energy storage (TES) purposes by incorporating microencapsulated phase material (MicroPCM) into a wood fiber-starch (WFC). Characterization studies on the MicroPCM/WFC material included the assessments of microstructures via scanning electron microscope (SEM) and chemical structures using Fourier transform infrared spectrometer (FT-IR). The TES characteristics and thermal stability were determined through differential scanning calorimeter (DSC) and thermo-gravimetric analysis (TGA) techniques, respectively. The thermal conductivity and internal bonding strength properties of fabricated MicroPCM/WFC(50 wt%) composite was also evaluated as well as investigating its thermoregulation performance in lab-scale. SEM analysis confirmed a uniform structure with intact MicroPCM particles in the composite. DSC findings exposed the suitability of the composite for building TES practices. Thermal cycling examination revealed that the composite still wellpreserved its TES features after 600 heating and cooling cycles. Additionally, the composite showed a thermal conductivity of 0.1041 W/mK and an internal bonding strength of 0.04 N/mm2. Furthermore, thermoregulation performance test indicated that the introduction of MicroPCM in the WFC effectively reduced room temperature fluctuations compared to WFC without MicroPCM. The results suggest that the developed MicroPCM/WFC composite serves as a potential green solution for enhanced energy savings in building applications.
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    Physico-mechanical properties and thermal monitoring performance of thermal enhanced cement slurry-coated LWAs containing microencapsulated phase change material
    (Elsevier, 2024) Emiroglu, Mehmet; Ozguler, Alper Tunga; Nas, Memduh; Subasi, Serkan; Sari, Ahmet; Hekimoglu, Gokhan; Ustaoglu, Abid
    Over the past decade, phase change materials (PCMs) have emerged as promising solutions for thermal energy storage (TES) systems, aimed at minimizing heating and cooling energy requirements in buildings. Nevertheless, despite their potential, there are some significant challenges in effectively integrating PCMs into building components. As part of this study, lightweight aggregates (LWA) were coated with a cement slurry containing microencapsulated phase change material (MPCM) to produce lightweight concrete (LWC) with the aim of investigating its mechanical and thermal properties. The LWAs were coated with MPCM at proportions of 2.5%, 5%, and 7.5% of their weight, and an LWC-MPCM was produced using these coated aggregates. The LWC-MPCM exhibited a decrease in dry unit weight up to 1248 kg/m 3 and a reduction in thermal conductivity up to 0.60 W/ mK with negligible loss of strength. SEM examinations revealed that the cement slurry coating provided strong adhesion to the aggregates, resulting in a robust concrete-aggregate interface. The room with the LWC-MPCM experienced a decrease of approximately 0.23 degrees C in center temperature compared to the reference room during the daytime. Additionally, after sunset, the LWC-MPCM showed an increase of approximately 1 degrees C in room center temperature. These advantageous physico-mechanical and thermal properties establish LWC-MPCMs as promising and energy-efficient components for producing thermo-regulative building materials.
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    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.
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    Thermal energy storage and mechanical enhancement of cement composites containing PCM-impregnated and cement-slurry coated pumice aggregates
    (Elsevier, 2025) Gencel, Osman; Ozguler, Alper Tunga; Guler, Onur; Ustaoglu, Abid; Hekimoglu, Gokhan; Sari, Ahmet; Emiroglu, Mehmet
    In the field of thermal energy management and building materials, PCM has been impregnated into aggregates and added to cement to produce composite concretes. However, challenges such as PCM leakage and poor interfacial bonding have limited their widespread application. To address these issues, this study utilized pumice aggregates with exceptional porosity, impregnated with PCM and coated with cement slurry, to develop enhanced composite concretes. The produced composites were characterized through compressive strength tests, thermal conductivity measurements, ultrasonic pulse velocity analysis, and detailed thermal regulation experiments under dynamic solar radiation. Thermal regulation experiments were conducted using thermal imaging under real-time heating and cooling processes. Results demonstrated that PCM-impregnated aggregates enhanced the thermal stability of concrete, with surface temperatures on PCM-based composites (MAL-2) being approximately 5 degrees C lower during heating compared to control samples (MAL-K). During the cooling process, MAL-2 exhibited delayed temperature reduction, stabilizing surface temperatures around 1 degrees C higher than MAL-K due to PCM's latent heat release. Experimental outcomes further presented that an increasing proportion of PCM-impregnated aggregates significantly reduced porosity from 13.55 % to 7.87 % and improved compressive strength from 12.7 MPa to 16.81 MPa. Thermal conductivity increased from 0.5706 to 0.7058 W/mK, while water absorption decreased from 13.94 % to 7.13 %. Ultrasonic pulse velocity values increased from 2.49 km/s to 2.58 km/s, indicating enhanced matrix integrity. This design, offering superior thermal regulation and mechanical performance, holds great promise for applications in energy-efficient building materials and sustainable construction practices.