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"Experimentation on and implementation of phase-change materials for thermal storage is attracting increasing attention by those seeking a potential resolution to energy issues. This study investigates beeswax as a high thermal-capacity phase-change material with the objective of analyzing the thermal properties and behaviors of beeswax/CuO nano-PCM. The study uses differential scanning calorimetry apparatus to measure the melting temperature and thermal capacity of nano-PCMs. The study found nano-PCM melting temperatures of 63.62°C, 63.59°C, 63.66°C, 63.19°C, and 62.45°C at 0.05, 0.1, 0.15, 0.2, and 0.25 wt%, respectively. FTIR testing found no chemical reaction between CuO and beeswax. The existence of CuO nanoparticles enhanced thermal conductivity of beeswax but reduced its heat capacity. However, the change in latent heat caused no significant effects in the performance of beeswax/CuO. Thus, the results showed that heat transfer of composite beeswax/CuO melts faster than base phase-change material"

"The enhancement of heat transfer performance in heat exchanger is achieved by reducing the size of the hydraulic diameter or by using a working fluid that has a better thermal conductivity compared to conventional working fluids. The application of a small hydraulic diameter can be found in the microchannel heat exchanger (MCHE). The design and the testing of the MCHE were done in this research. The MCHE was tested with several working fluids, such as the distilled water, the Al2O3-water nanofluids at 1%, 3% and 5% volume concentration, and the SnO2-water nanofluids at 1% volume concentration. The temperature of inlet and outlet were set at 50o C and 25o C, respectively. The variations of flow rate at the inlet were applied from 100 ml/min up to 300 ml/min. The addition of nanoparticle in the base fluid was proven to improve the heat transfer of the MCHE, the 5% Al2O3-water and 1% SnO2-water nanofluids are able to absorb the heat 9% and 12% higher than the base fluid. The overall heat transfer coefficient of MCHE with 5% Al2O3-water and 1% SnO2-water nanofluids were 13% and 14% higher than the base fluid."

"Peningkatan konsumsi energi pada aplikasi bangunan merupakn isu global dunia. Penelitian ini berkaitan dengan pemanfaatan Phase Change Material PCM untuk penyimpanan termal. Konsep ini mendapat perhatian besar sebagai solusi untuk mengurangi konsumsi energi pada aplikasi bangunan. PCM Lilin memiliki kapasitas termal yang tinggi dipelajari dalam penelitian ini. Tujuan dari penelitian in adalah untuk mengukur dan menganalisis sifat termal lilin lebah/graphene sebagai PCM. Titik leleh, kapasitas kalor dan kalor laten diukur menggunakan Differential Scanning Calorimetry DSC , dan konduktivitas termal diukur menggunakan alat ukur konduktivitas meter. Untuk mengetahui perubahan morphologi PCM akibat pengaruh nanopartikel dan viskositasnya juga diteliti. Berdasarkan hasil DSC, kalor laten lilin lebah/graphene meningkat sebesar 22,5 pada 0,3 wt . Konduktivitas termal lilin lebah/graphene adalah 2,8 W/m.K pada 0,3 wt . Dengan penambahan nanographene meningkatkan kalor laten dan konduktivitas termal nano PCM lilin lebah/graphene. Oleh karena itu, berdasarkan hasil penelitian ini, lilin lebah/graphene disimpulkan memiliki potensi untuk digunakan pada aplikasi bangunan dengan harapan dapat mengurangi konsumsi energi.

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Increased energy consumption in buildings is a worldwide issue. This research is concerned with the implementation of a phase change material for thermal storage. This concept has gained great attention as a solution to reduce energy consumption in buildings. Beeswax, which is a phase change material with a high thermal capacity, is investigated in this research. This paper is intended to measure and analyze the thermal properties of beeswax graphene as a phase change material. The melting temperature, thermal capacity and latent heat were determined using differential scanning calorimetry DSC , and the thermal conductivity was investigated using a thermal conductivity measurement apparatus. To discover the change in the physical properties due to the effect of nanoparticles, the viscosity of the material was investigated as well. Based on the result from the DSC, the latent heat of 0.3 wt beeswax graphene increased by 22.5 . The thermal conductivity of 0.3 wt beeswax graphene was 2.8 W m.K. The existence of graphene nanoplatelets enhanced both the latent heat and thermal conductivity of the beeswax. Therefore, based on this result, beeswax graphene is concluded to have the potential to reduce energy consumption in buildings."

"ABSTRAKPemanfaatan Thermal Energy Storage atau TES menjadi salah satu teknologi yang dikembangkan untuk mengatasi krisis energi. Sistem yang digunakan TES meliputi pemanfaatan kalor sensibel, laten, dan thermo-chemical, namun sistem TES dengan kalor laten dianggap paling efektif karena kemampuannya untuk menyimpan dan memancarkan energi dalam jumlah besar namun volume yang dipakai relatif kecil. Material yang digunakan pada TES laten disebut dengan phase change materials (PCM). Pada penelitian ini, PCM minyak kelapa ditambahkan dengan nanopartikel graphene untuk meningkatkan sifat termal dari PCM sebanyak 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, dan 0.5 wt%, sehingga terbentuk menjadi komposit bio-based PCM. Kalor laten, titik leleh, titik beku, dan kalor jenis dari komposit PCM diuji dengan Differential Scanning Calorimetry (DSC). Konduktivitas termal diukur dengan KD2 Pro Thermal Analyzer dan kestabilan termal PCM diuji dengan Thermogravimetric Analysis (TGA). Selain itu, pengujian struktur dilakukan dengan Transmission Electron Microscopy (TEM) untuk melihat mikrostruktur dan morfologi komposit PCM, dan Fourier Transfer Infrafred (FTIR) untuk melihat stabilitas kimiawi komposit PCM. Didapatkan bahwa penambahan graphene pada PCM minyak kelapa dapat mempengaruhi konduktivitas termal, kalor laten, kalor jenis, dan kestabilan termal.

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ABSTRACTThe utilization of Thermal Energy Storage or TES become one of the developed technologies to overcome energy crisis. Systems that are used in TES include sensible heat, latent heat, and thermochemical, but TES with latent heat system is considered as the most effective due to its ability to store and release heat in large amount with relatively low volume used. Material used in latent TES is called phase change materials (PCM). In this research, coconut oil as PCM was being added with graphene to improve its thermal conductivity with mass fraction of 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, dan 0.5 wt%. Latent heat, melting temperature, freezing temperature, and specific heat were tested with Differential Scanning Calorimetry (DSC). Thermal conductivity was measured with KD2 Pro Thermal Analyzer and thermal stability is tested with Thermogravimetric Analysis (TGA). Other than that, the structure of bio based PCM was tested with Transmission Electron Microscopy (TEM) to observe its morphology and Fourier Transfer Infrafred (FTIR) to see its chemical stability. It was obtained that graphene addition does affect thermal conductivity, latent heat, specific heat, and thermal stability of coconut oil as bio based PCM."

"The objective of the present study is to investigate numerically the problem of melting phase change material (PCM) containing paraffin where one of the area interfaces moves with time and wherein the result of the fusion between the coupling in the solid phase conduction and convection in the liquid phase, then processes the effect of integration of the material in the walls of the building in order to increase its thermal inertia to validate the result ,we will study the numerically transient and performance of a fixed bed filled with uniform spheres, randomly arranged and each containing a (PCM). So we use a two-dimensional theoretical model applied in two separate phases; it was used to predict the temperature distribution of the fluid and the fusible material along the bed in the energy storage method."

"Stearic acid/besi oksida (Sa/Fe3O4) dan stearic acid/besi oksida/titanium dioksida (Sa/Fe3O4/TiO2) sebagai material berubah fasa telah disintesis dengan mencampurkan Fe3O4 dan Fe3O4/TiO2 ke dalam stearic acid melalui teknik dispersi. Karakterisasi kemudian dilakukan dengan pengukuran X-ray Diffraction (XRD), Energy Dispersive X-Ray (EDX), Fourier-Transform Infrared Spectroscopy (FTIR) dan Field Emission Scanning Microscopy (FESEM) untuk investigasi struktur, unsur, mode vibrasi dan morfologi dari sampel. Sifat termal dari sampel juga dikarakterisasi untuk mengetahui kemampuan sampel sebagai media penyimpanan kalor melalui pengukuran Differential Scanning Calorimetry (DSC) dan Thermogravimetric Analysis (TGA). Hasil yang didapat menunjukkan bahwa Sa/Fe3O4 dan Sa/Fe3O4/TiO2 memiliki nilai kalor laten, kapasitas panas, dan stabilitas termal yang lebih baik daripada stearic acid.

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Stearic acid/iron oxide (Sa/Fe3O4) and stearic acid/iron oxide/titanium dioxide (Sa/Fe3O4/TiO2) as a phase change material were synthesized by mixing the Fe3O4 and Fe3O4/TiO2 into the stearic acid. All of the samples were characterized by X-ray Diffraction (XRD), Energy Dispersive X-Ray (EDX), Fourier-Transform infrared spectroscopy (FTIR) and Field Emission Scanning Microscopy (FESEM) for structural properties, elemental investigation, morphologies and vibrational modes of the samples. The thermal properties of the sample were also characterized to investigate the thermal storage ability by Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). The results show that the Sa/Fe3O4 and Sa/Fe3O4/TiO2 have better latent heat, specific heat, and thermal stability than the stearic acid itself.

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"Penelitian ini memiliki tujuan untuk menghasilkan Phase Change Material (PCM) organik berbasis natural wax dan aplikasinya pada manajemen termal bangunan. Selain itu untuk mengetahui pengaruh nanopartikel, yaitu grafena dan MAXene dalam komposit PCM yang dihasilkan melalui metode impregnasi basah. Natural wax yang digunakan adalah soy wax, paraffin wax dan palm wax. Nanopartikel grafena dan MAXene (Ti3AlC2) ditambahkan sebesar 0,1 – 1 wt.% ke dalam PCM untuk meningkatkan konduktivitas termal dan stabilitas termal komposit nano-PCM. Uji siklus termal (500 – 5000 siklus) dan aplikasi manajemen termal hanya dilakukan pada PCM soy wax murni yang memiliki performa terbaik berbanding natural wax yang lain. Alat uji siklus termal berbasis termoelektrik, penambahan 4 modul, desain sederhana, sistem kerja otomatis dan simultan juga dirancang untuk meningkatkan efisiensi waktu pengujian. Nano-PCM dikarakterisasi menggunakan Scanning Electron Microscope- Energy Dispersive X – Ray Spectroscopy (SEM-EDS), Differential Scanning Calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR) dan konduktivitas termal. Hasil konduktivitas termal komposit nano-PCM soy wax-grafena dan soy wax-MAXene masing-masing adalah 0,88 W/mK dan 0,85 W/mK pada 1 wt%. Konduktivitas termal pure soy wax (0,18 W/mK) meningkat sebesar 6,01% untuk soy wax+grafena dan 5,71% untuk soy wax+MAXene. Hasil DSC menunjukkan soy wax dengan penambahan masing-masing grafena dan MXene 0,1 wt% memiliki kenaikan titik leleh sebesar 15% dan 16% serta penurunan titik beku sebesar 14% dan 13%. Hasil uji siklus termal menggunakan pure soy wax dengan alat thermal cycle yang didesign menghasilkan 13 siklus dalam waktu sangat efisien hanya 1 jam pengujian dan setelah 5000 siklus mengalami penurunan ΔH sebesar 60%. Uji performa PCM pada prototipe model dinding bangunan ukuran 101 x 50 x 80 cm untuk skala 1:5 mengunakan polywood dilakukan dengan mengenkapsulasi pure soy wax dalam kantong aluminium foil sebesar 250 g dan ketebalan 1 cm dan pengujian dilakukan selama 24 jam. Aplikasi manajemen termal menunjukkan pure soy wax pack menghasilkan penyerapan panas sebesar 10% dari 41oC menjadi 37oC dibandingkan dengan prototipe bangunan tanpa lapisan soy wax pack. Material maju PCM berbasis pure soy wax memiliki potensi sebagai material manajemen termal pada aplikasi bangunan dan mengoptimalkan penggunaan energi untuk sistem pendinginan pada bangunan.

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This study aims to produce an organic Phase Change Material (PCM) based on natural wax and its application to the thermal management of buildings. In addition, graphene and MAXene in PCM composites were produced through the wet impregnation method to determine the effect of nanoparticles. Natural wax used is soy wax, paraffin wax, and palm wax. Graphene and MAXene (Ti3AlC2) nanoparticles were added at 0.1-1 wt.% to the PCM to increase the thermal conductivity and thermal stability of the nano-PCM composite. Thermal cycle tests (500-5000 cycles) and thermal management applications are only carried out on pure PCM soy wax which has the best performance compared to other natural waxes. Thermoelectric-based thermal cycle test equipment, the addition of 4 modules, a simple design, and an automatic and simultaneous working system are also designed to increase the efficiency of testing time. Nano-PCM was characterized using Scanning Electron Microscope- Energy Dispersive X-Ray Spectroscopy (SEM-EDS), Differential Scanning Calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), and thermal conductivity. The thermal conductivity of soy wax-graphene and soy wax-MAXene nano-PCM composites were 0.88 W/mK and 0.85 W/mK at 1 wt%, respectively. The thermal conductivity of pure soy wax (0.18 W/mK) increased by 6.01% for soy wax+graphene and 5.71% for soy wax+MAXene. DSC results showed that soy wax with the addition of graphene and MXene 0.1 wt%, respectively, had a melting point increase of 15% and 16% and a freezing point depression of 14% and 13%, respectively. The results of the thermal cycle test using pure soy wax with a thermal cycle tool designed to produce 13 cycles in a very efficient time of only 1 hour of testing and after 5000 cycles the H decreased by 60%. PCM performance test on a prototype building wall model measuring 101 x 50 x 80 cm for a scale of 1:5 using polywood was carried out by encapsulating pure soy wax in an aluminum foil bag of 250 g and a thickness of 1 cm and the test was carried out for 24 hours. Thermal management application shows that pure soy wax pack produces 10% heat absorption from 41oC to 37oC compared to building prototype without soy wax pack coating. Advanced PCM materials based on pure soy wax have potential as thermal management materials in building applications and optimize energy use for cooling systems in buildings."