Research Article
Renewable Energy Resources and Technologies
Mohammed Ibrahim Shaba; Aliyu Mohammed; Dauda Solomon Musa; Balami Ayuba Audu; Yunusa Baba Katamba
Abstract
Internationally exploited lubricants are derived from coal and petroleum. Due to their high consumption and effects of their long-term pollution on the environment, it is imperative to use renewable and cheap feedstock for the synthesis of bio-based lubricants. This study presents the synthesis and optimization ...
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Internationally exploited lubricants are derived from coal and petroleum. Due to their high consumption and effects of their long-term pollution on the environment, it is imperative to use renewable and cheap feedstock for the synthesis of bio-based lubricants. This study presents the synthesis and optimization process of Ethylene Glycol (EG) based bio-lubricant from palm kernel oil. Palm Kernel Methyl Ester (PKME) was synthesized at a reaction time of 60 min, a molar ratio of oil: methanol 1:6, a temperature of 60 oC, and catalyst of 1 % wt/wt (in-situ transesterification) via reactive extraction. Box–Behnken design (BBD) in response surface methodology (RSM) was applied to this experimental layout. The effects of molar ratio, reaction time, and temperature on the synthesis of palm kernel biolubricant (PKBL) were evaluated. The PKBL structure was characterized by Fourier Transform Infra-Red (FT-IR) and Gas Chromatography-Mass Spectrophotometer (GC-MS) analysis, showing favorable lubricating properties. The PKME yielded 94.53 wt% based on the weight of the oil, while transesterification of the in situ derived PKME with EG yielded 93.08 wt% of the EG ester (Biolubricant). The maximum biolubricant recovery was 81.48 wt% obtained at a molar ratio of 3:1, time of 2.48 h, and temperature of 135 oC. The temperature and mole ratio were established to be the most significant terms. PKBL characteristics conformed to ISO VG criteria and had high potential for biolubricant feedstock.
Research Article
Advanced Energy Technologies
Tuhid Pashaee Golmarz; Sajad Rezazadeh; Narmin Bagherzadeh
Abstract
In this paper, a three-dimensional, single-phase proton-exchange membrane fuel cell (PEMFC) is studied numerically. Finite volume method was used for solving the governing equations and, consequently, the numerical results were validated by comparing them with experimental data, which showed good agreement. ...
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In this paper, a three-dimensional, single-phase proton-exchange membrane fuel cell (PEMFC) is studied numerically. Finite volume method was used for solving the governing equations and, consequently, the numerical results were validated by comparing them with experimental data, which showed good agreement. The main objective of this work is to investigate the effect of a novel gas channel shape– by applying sinusoidal gas channel- on the cell performance and mass transport phenomena. Some parameters such as oxygen consumption, water production, protonic conductivity, and temperature distribution for two cell voltages were studied, and the results were compared with respect to conventional and new models. The results indicated that the new novel model showed better performance than the conventional model, especially at low cell voltages, causing an increase in oxygen consumption and water production. Therefore, based on a number of investigated relations, a higher rate of current density was obtained, thus enhancing the fuel cell performance. This is because the incoming species path to the gas channels in the new model becomes longer. Therefore, the diffusion of the species toward the electrochemical reaction area increased.
Research Article
Renewable Energy Resources and Technologies
Mojtaba Moravej; Fatemeh Namdarnia
Abstract
Solar water heaters are good tools for saving fuel. The main component of these water heaters is collectors, which are responsible for absorbing solar energy and transferring it to the working fluid with the least heat dissipation. The present study is an experimental study of the performance of the ...
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Solar water heaters are good tools for saving fuel. The main component of these water heaters is collectors, which are responsible for absorbing solar energy and transferring it to the working fluid with the least heat dissipation. The present study is an experimental study of the performance of the solar semispherical collector with 1 m2 of absorber area at different volumetric flow rates. Water was used as the working fluid with the volumetric flow rate between 0.005-0.0166 kg/s, and the experiment was conducted in the ASHRAE 93 standard conditions. The results showed that the efficiency of semispherical solar collector increased as the flow rate of the working fluid increased, such that the highest efficiency, which is 67%, belonged to mass flow rate 0.0166 kg/s. In addition, the difference between outlet and inlet temperatures decreased due to the system being closed during the test. In addition, according to the experiments, the reduction of radiation and wind speed did not have any significant effect on the efficiency and outlet temperature of the collector. Finally, parameters such as inlet and outlet temperature of collector, ambient temperature, ambient radiation intensity and their effect have been investigated empirically on the collector efficiency graph.
Research Article
Renewable Energy Resources and Technologies
Mohammad Ahmadzadehtalatapeh; Shahrokh Khaki
Abstract
The application of phase change material (PCM) for energy conservation purposes in the residential buildings was investigated in the present study. Two types of building in terms of materials as the lightweight building (LWB) and heavyweight building (HWB) located in a high cooling load demanding region ...
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The application of phase change material (PCM) for energy conservation purposes in the residential buildings was investigated in the present study. Two types of building in terms of materials as the lightweight building (LWB) and heavyweight building (HWB) located in a high cooling load demanding region of Iran were considered for the study. Different types of PCM from organic and inorganic categories were examined to determine the most appropriate type of the buildings in terms of indoor air conditions and yearly required cooling load. The buildings in the existing form and with an added layer of PCM were simulated hourly, and indoor air conditions and yearly cooling loads were determined. EnergyPlus software was used for this purpose. The study revealed that the LWB with the added layer of calcium chloride hex hydrate (CCH) had the minimum yearly required cooling load with about 39.8 GJ, and 25.7% reduction in the yearly cooling load was observed and the HWB had the best performance in terms of yearly required cooling load with the added n-eicosone (N.EIC) layer with about 28.8 GJ, which is a 47.1% reduction in the yearly cooling load. After determining the proper PCM for the buildings, the recommended PCM was planned to be positioned in the external layer, mid-layer, and internal layer to examine the position effect on the yearly required cooling load
Research Article
Advanced Energy Technologies
Tamer Nabil; Mohamed Khairat Dawood; Tamer Mansour
Abstract
Since the renewable resources of energy have become extremely important, especially wind energy, scientists have begun to modify the design of the wind turbine components, mainly rotor blades. Aerodynamic design considered a major research field related to power production of a small horizontal wind ...
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Since the renewable resources of energy have become extremely important, especially wind energy, scientists have begun to modify the design of the wind turbine components, mainly rotor blades. Aerodynamic design considered a major research field related to power production of a small horizontal wind turbine, especially in low wind speed locations. This study displays an approach to the selection of airfoil and blade design utilized in small horizontal wind turbines with low cut-in speed and with no gear box. Modeling of the flow depends on Computational Fluid Dynamics (CFD) and theory of Blade Element Momentum (BEM) methodologies. QBlade used (BEM) for wind turbine simulation and integrated with XFOIL for airfoils design to ensure the requested characteristics for wind turbine performance. MATLAB is used to calculate the final design parameters to be modeled in SOLIDWORK. The flow dynamics are explored with the aid of ANSYS Fluent 16. The application of specially designed blades grants start up at lower wind speeds. The designed blade is fabricated from polyurethane foam. Experimental study confirmed that, at low average wind velocity (4m/s), the fabricated small-scale horizontal wind turbines are considered to be a positive way to supply electricity with an average power rate of 9watt and efficiency of 8%.
Research Article
Renewable Energy Resources and Technologies
Seyed Amir Hossein Zamzamian; Mohsen Mansouri
Abstract
The enhancement of the thermal performance of Vacuum Tube Solar Collectors (VTSC) was studied by using alumina nanofluid as working fluid. VTSC is a simple and commonly utilized type of collector. This study established the heat transfer experimental model of all glass VTSCs used in a forced-circulation ...
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The enhancement of the thermal performance of Vacuum Tube Solar Collectors (VTSC) was studied by using alumina nanofluid as working fluid. VTSC is a simple and commonly utilized type of collector. This study established the heat transfer experimental model of all glass VTSCs used in a forced-circulation solar water heating system using alumina nanofluid as base fluid. Al2O3 (with an average particle size of 15 nm) nanoparticles were provided and utilized to prepare nanofluids at a low mass concentration (0.5–1 wt.%). The thermal performances of VTSC were 15.3%, 25.7%, and 27.2% for the deionized water and Al2O3/water nanofluids with 0.5 and 1.0 wt. % as the working fluid, respectively. Generally, for Al2O3/water nanofluids with mass concentrations of 0.5 and 1.0 wt. %, the thermal performance increased by 67.9% and 77.7%, respectively, superior to that of vacuum tube using deionized water as the working fluid. Experimental results also showed that, for all three experimental tests, the thermal efficiency of the VTSC would increase by enhancing the average solar radiation.
