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Temperature is a significant factor to consider when evaluating the performance of the PVT system. Further-more, Phase Change Material (PCM) will be introduced in the Solar PVT model. Phase change materials contribute to the temperature adjustment function in several methods. In this paper, a comprehensive 3-dimensional model of photovoltaic thermal (PVT) system are developed to investigate the effects of PCM on the performance and efficiencies of the system. The findings highlighted to investigated on the surface temperature effect on various diameter of PVT-PCM. [ABSTRACT FROM AUTHOR]

Advances in nanotechnology today vary widely when viewed from the background of its application, the volume of nanoparticles has become the focus of researchers in the last decade. Hybrid nanoparticles are advances in the world of nanotechnology in which nanoscales of different sizes are added to each other using either the one-step method or the two-step method. This study intends to examine the hybrid titanium oxide-aluminium oxide (TiO2−Al2O3) nanoparticles by looking at the ratio of the volume to mass of different nanoparticles with different proportions of TiO2 (80%) and Al2O3 (20%) nanoparticles added with basic liquid with a fixed volume concentration of 0.1%. Ultrasonic testing and magnetic stirring ensure the stability of nanofluids as well as a way to synthesize nanofluids. Characterization of hybrid nanoparticles using x-ray diffraction (XRD), fourier transform infrared (FTIR) and scanning electron microscopy (SEM) analysis to determine the phase of the crystalline material and see the morphology of the microstructure. The incorporation of TiO2+Al2O3 nanoparticles when viewed from the thermal conductivity and viscosity testing efficiently shows that the thermal conductivity has increased compared to the decreased viscosity, therefore hybrid nanofluids have a potential influence on the heat transfer system for increasing thermal conductivity and low viscosity. [ABSTRACT FROM AUTHOR]

This study is about the comparison between the effect of mixing of surfactant sodium dodecyl sulfate (SDS) and without surfactant on the oxide, which consists of Al2O3, TiO2, and CuO. Obtained by synthesis using a mass fraction of 0.1% SDS and 1 gram of Al2O3/TiO2/CuO dissolved in 1000 ml of distilled water and then stirred using a magnetic stirrer for 1 hour at a speed of 650 rpm. Furthermore, without surfactant, using 1 gram of Al2O3/TiO2/CuO was dissolved in 1000 ml of distilled water and then stirred using a magnetic stirrer. Then the ultrasonic process was for 1 hour to get more homogeneous nanoparticles. The addition of surfactants to nanofluids can increase the stability and viscosity of the nanofluids. Obtained from the results of the Viscometer test with temperature variations from 20 °C-60 °C, the values of viscosity, shear rate, and shear stress. Then tested on Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Fourier Transform Infra-Red (FTIR), and the results of the analysis of Conductivity Thermal and Specific Heat tests. This study aims to determine whether the addition of surfactant to oxide affects the value of viscosity, shear rate, shear stress, and thermal conductivity. [ABSTRACT FROM AUTHOR]

SWCNTSs nanofluids have high mechanical strength, good electrical conductivity, and high tensile strength. This research focuses on analyzing the thermophysical properties, heat transfer characteristics, and pressure drop of Single-Wall Carbon Nano Tube (SWCNT). Volume fractions used in nanofluids are 0.1%, 0.3%, and 0.5% and PVP surfactant 0.02% with distilled water as a base fluid (Aquades). SWCNTs nanoparticle characterization process was carried out by means of thermal conductivity test, and specific heat, viscosity test, density test, mettler toledo, FTIR (Fourier Transform Infra Red) test, XRD (X-Ray Diffraction) test, and SEM (Scanning Electron Microscope) test. The results obtained in this study include thermophysical properties, namely for the highest thermal conductivity of 0.690 W/m.oK, density of 1736.95 kg/m3, viscosity of 0.00166 kg/m3, and for specific heat of 3097.08 J/kg.oC, then for the heat transfer characteristics, the result is that it has an increase in the value of the heat transfer coefficient of 4.17 W/m2.°C, and the pressure drop value gets a value of 1.1968 N/m2. [ABSTRACT FROM AUTHOR]

Research on nanofluids has developed rapidly in the application of its heat mechanism to a machine's performance. Heat mechanisms in nanofluids have emerged as promising fluid heat transfers, as for example in applications as a coolant in Thermal Photovoltaic. This study will discuss the effect of the Hybrid Copper Oxide/Titanium Dioxide (CuO/TiO2) Nanofluida on the rheological properties using based water. The purpose of this study was to determine the rheological properties and dynamic viscosity of the hybrid Copper Oxide/Titanium Dioxide (CuO/TiO2) nanofluids based-water performance on system. Hybrid nanoparticles were used to synthesize nanofluids using a volume ratio of 50:50 at 1L of water. Begin by mixing both of nanoparticles CuO and TiO2 with based-water using a magnetic stirrer at a speed of 650 rpm for 60 minutes, then followed by an ultrasonic stirrer for 1 hour so that the two nanoparticles become more homogeneous. The dynamic viscosity obtained using the NDJ-8S Viscometer uses variations in temperature of 20 °C, 30 °C, 40 °C, 50 °C, 60 °C with speeds of 6 rpm, 12 rpm, 18 rpm, 24 rpm, and 30 rpm. The results obtained in the form of viscosity, shear rate, and shear stress. [ABSTRACT FROM AUTHOR]

This research studied the effect of CTAB and PVP surfactants on the rheological properties of DWCNTs and MWCNTs nanomaterials in water-based nanofluids. Surfactants are used to bind between nanoparticles and fluid molecules, because some nanoparticles experience sedimentation on the nanofluid, so the addition of the surfactant is necessary. Mixing is carried out using a magnetic stirrer for 1 hour at a speed of 650 rpm, followed by sonication for 1 hour. This mixing uses a mass fraction ratio of 0.1% nanomaterial and 1:1 surfactant with nanomaterial. Nanofluids were tested by Scan Electron Microscopy (SEM), X-Ray Diffraction (XRD), and Fourier Transform Infra-Red (FTIR). The NDJ-8S viscometer is a tool for finding the viscosity value of nanofluids with temperature variations of 20 °C, 30 °C, 40 °C, 50 °C and 60 °C using speeds of 6, 12, 18, 24 and 30 rpm. The results of the research included the effect of surfactant and temperature in the nanofluid on the viscosity and shear stress of the DWCNTs and MWCNTs nanofluids. [ABSTRACT FROM AUTHOR]

The experimental process carried out in this paper is to determine the convection heat transfer coefficient, overall heat transfer coefficient, and nanofluid heat transfer rate based on DWCNT (double-wall carbon nanotube) nanotubes applied to a shell and tube heat exchanger. The advantage of using DWCNT nanoparticles is the high thermal conductivity value. The volume fractions of nanoparticles were 0.1%, 0.3%, and 0.5% with the addition of PVP surfactant. Experimental tests were conducted to determine the heat transfer performance applied to a shell and tube type heat exchanger with upright baffles. This study aims to improve the heat transfer performance by utilizing nanofluids based on DWCNTs nanoparticles. As a result, using DWCNT nanofluids instead of base fluids increases the convective heat transfer coefficient values and overall heat transfer. The increase in the volume fraction of DWCNTs nanoparticles is also accompanied by an increase in the heat generated. The highest thermal conductivity was obtained by adding 0.5% volume of DWCNTs nanoparticles, which was 0.640 W/m.K. The highest heat transfer rate was produced by adding 0.5% volume fraction and 0.02% PVP with a result value of 70.191 W. [ABSTRACT FROM AUTHOR]

In this journal, we present about the thermophysical and rheological properties of MWCNT (Multi-Walled Carbon Nanotubes) in Water-Based Nanofluid with various surfactants added. Cetyl Trimethyl Ammonium Bromide (CTAB), Sodium Dodecyl Sulfate (SDS), and Poly Vinyl Pyrrolidone (PVP) are used as a surfactant to be mixed nanofluids. The synthesis was carried out using magnetic stirring and sonicated at 650 rpm for 1 hour with a mass fraction ratio of 0.1%. Then tested on KD 2 Pro Thermal, Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR), and X-Ray Diffraction (XRD). Viscosity was searched using NDJ-8S Viscometer with temperature variations of 20 ℃, 30 ℃, 40 ℃, 50 ℃, and 60 ℃ with rotations of 6, 12, 18, 24, and 30 rpm. So that the results obtained the value of thermal conductivity, specific heat, analysis of the surface's topography and composition, phase identification of a crystalline material, functional group, viscosity, shear rate, and shear stress. The result of our research is to be able to choose the best surfactant for MWCNT nanofluids as needed. It is hoped that the selection of appropriate surfactants for nanofluids can be further studied to improve the stability and dispersion of nanofluids for industrial production and long-term use. [ABSTRACT FROM AUTHOR]

The most used instrument for solar energy harvesting is flat plate solar collector (FPSC). To improve the performance FPSC to get the optimal energy multi-walled carbon nanotubes (MWCNT) used on flat plate solar collector. This study describes the effect of synthesis of MWCNT-water based with concentrate ratio variations 0,1%, 0,3%, 0,5% and light intensity variations 415 W/m2, 515 W/m2 and 615 W/m2 with radiation from the sun simulator of 750 W/m2. Every light intensity was tested with different MWCNT-water nanofluids with concentrate variations 0,1%, 0,3%, 0,5%. The test was carried out 52 times for the collection of experimental data to provide valid test result. This study provides significant results on the use of nanofluids as a substitute for 0.5% multi-wall carbon nanotubes-water as a heat transfer fluid in improving the thermophysical properties that are superior to the base fluid. Increased light intensity and volume of nanoparticles also provide significant results on the performance of FPSC. In this paper, the greatest efficiency was found in the use of nanofluids and radiation intensity of 615 W/m2 with a volume of 0.5% nanoparticles with an efficiency of 90.45%. Increasing the fraction of nanoparticles into nanofluids provides the greatest efficiency-enhancing effect on the performance of FPSC. [ABSTRACT FROM AUTHOR]

The current use of energy has begun to lead to the use of renewable energy from nature, one of which is wind energy. A gust of wind can be extracted into new energy using the help of wind power plants. VAWT (Vertical Axis Wind Turbine) is a type of wind turbine whose main axis is arranged transversely to the direction of the wind and its main components are located at the base of the turbine. This study aims to determine the magnitude of the effect of variations in wind velocity and the number of blade levels of Hybrid turbines on turbine performance and aims to determine which variation is the most effective in extracting wind energy. This study uses a quasi-experimental method on the object of research in the form of vertical axis wind turbines of the Darrieus, Savonius and Hybrid types with variations in wind velocity of 3, 5 and 7 m/s and variations in the number of levels of one and two levels of Hybrid blades. The research data was obtained through simulation with the help of ANSYS 17.0 software using the CFD method (Computational fluid dynamics). The output of this research is the value of power, torque, tangential speed and efficiency generated by the wind turbine. The results showed that the wind velocity and the number of blade levels greatly affect the performance of the wind turbine. In this study, it was found that from the results of simulation testing using the CFD method, the best efficiency value was found in the one-stage Hybrid Darrieus-Savonius turbine at a wind velocity variation of 7 m/s of 3,31256% and Hybrid Darrieus-Savonius. Savonius two levels at 5 m/s wind velocity variation of 4,53786%. [ABSTRACT FROM AUTHOR]