Gilani N.,University of Tehran |
Hendijani A.D.,University of Tehran |
Seyedin F.,Sharif Energy Research Institute
Journal of Energy Resources Technology, Transactions of the ASME | Year: 2017
this study, the applicability of functionalized carbon nanotubes (CNTs) as an additive to increase ethanol heating value has been examined. CNTs were grown within pores of anodic aluminum oxide (AAO), fabricated at the voltages of 40 V and 60 V. Accordingly, CNTs with tubular and Y-branched structures were obtained. Then, CNTs were carboxylated in 10 ppm solution of ethanol and its heating value was examined. Results indicated that Y-branched CNTs only lead to 0.1% increase in ethanol heating value. Tubular CNTs with 16 nm wall thickness raised heating value up to 0.38%. Therefore, Y-branched CNTs resulted in lower increase in ethanol heating value than tubular CNTs. In order to enhance the heating value of this sample, the amine groups including butylamine, dodecylamine, and octadecylamine were used to functionalize the related CNTs. The results showed that the heating values of 10 ppm solutions of functionalized CNTs are higher than pure ethanol about 0.65-2.4%. Moreover, the highest heating value belonged to the solution containing CNTs functionalized by Octadecylamine. Various concentrations of these functionalized CNTs showed that they were stable in 80 ppm ethanol solutions and their heating value and octane number increased by 6.4% and 7.8%, respectively. © 2017 by ASME.
Sima A.H.,Sharif Energy Research Institute |
Salari A.,Sharif University of Technology |
Shafii M.B.,Sharif University of Technology
Journal of Micro/ Nanolithography, MEMS, and MOEMS | Year: 2015
A reciprocating single-chamber micropump is designed and experimentally tested. The actuation technique of the pump is based on Lorentz force acting on an array of low-weight microwires placed on a flexible membrane surface. A square-wave electric current (5.6 and 7.8 A) with a low-frequency range (5.6 to 7.6 Hz) is applied through the microwires in the presence of a perpendicular magnetic field (0.08 to 0.09 T). The resultant oscillating Lorentz force causes the membrane to oscillate with the same frequency, and pushes the fluid to flow toward the outlet using a high-efficiency ball-valve. The micropump has exhibited a maximum efficiency of 2.03% with a flow rate as high as 490 μl/s and back pressure up to 1.5 kPa. Having a high self-pumping frequency of Fsp=32.71/min compared to other micropumps, our proposed pump is suitable for a wide range of applications specifically for biofluid transport. © 2015 Society of Photo-Optical Instrumentation Engineers (SPIE).
Tamsilian Y.,Sharif University of Technology |
Tamsilian Y.,Sharif Energy Research Institute |
Ebrahimi A.N.,Sharif University of Technology |
Ebrahimi A.N.,Research Institute of Oil and Gas Industry |
Ramazani S.A. A.,Sharif University of Technology
Journal of Dispersion Science and Technology | Year: 2013
This study presents economic and formation investigations on hydration effects by looking at natural gas hydrate (NGH) storage and transportation processes and formation conditions. The investigation includes experiments with methane. The obtained results show that the methane formation time increased linearly as the subcooling temperature decreased. Furthermore, the economic result indicates that the energy consumption parameter is appropriate for examining resource consumption for a system that, in turn, results in optimal capital investment through the storage and transportation process of NGH. The results also show that energy consumption increases logarithmically as the hydrate formation pressure increases. Finally, the study shows that the initial cost of the NGH transport chain is lower than the initial liquefied natural gas (LNG) transport cost. © 2013 Copyright Taylor and Francis Group, LLC.
Jafari Mosleh H.,Sharif University of Technology |
Mamouri S.J.,Sharif University of Technology |
Shafii M.B.,Sharif University of Technology |
Hakim Sima A.,Sharif Energy Research Institute
Energy Conversion and Management | Year: 2015
The solar collectors have been commonly used in desalination systems. Recent investigations show that the use of a linear parabolic through collector in solar stills can improve the efficiency of a desalination system. In this work, a combination of a heat pipe and a twin-glass evacuated tube collector is utilized with a parabolic through collector. Results show that the rate of production and efficiency can reach to 0.27 kg/(m2 h) and 22.1% when aluminum conducting foils are used in the space between the heat pipe and the twin-glass evacuated tube collector to transfer heat from the tube collector to the heat pipe. When oil is used as a medium for the transfer of heat, filling the space between heat pipe and twin-glass evacuated tube collector, the production and efficiency can increase to 0.933 kg/(m2 h) and 65.2%, respectively. © 2015 Elsevier Ltd. All rights reserved.
Rajabi-Ghahnavieh A.,Sharif Energy Research Institute |
Fotuhi-Firuzabad M.,Sharif University of Technology |
Othman M.,University Technology of MARA
IET Generation, Transmission and Distribution | Year: 2015
For a power transfer path, total transfer capability (TTC) represents maximum power that can be transferred over the transmission system. Unified power flow controller (UPFC) is a device that can be used to increase in TTC. This study presents a new method for optimal UPFC application to minimise power loss while enhancing TTC. Based on UPFC injection model, the solution region of UPFC parameters is first found using the proposed method to maximise TTC. It then searches the solution region to find optimal UPFC control mode and setting to minimise system power loss. The proposed method is applied to the IEEE-Reliability Test System and the UPFC application impact are evaluated. Comparative studies are conducted between the TTC results obtained by the proposed method with those obtained using the existing approaches. © The Institution of Engineering and Technology 2015.
Maroufmashat A.,Sharif University of Technology |
Seyyedyn F.,Sharif Energy Research Institute |
Roshandel R.,Sharif University of Technology |
Bouroshaki M.,Sharif University of Technology
ASME 2012 10th International Conference on Fuel Cell Science, Engineering and Technology Collocated with the ASME 2012 6th International Conference on Energy Sustainability, FUELCELL 2012 | Year: 2012
Hydrogen is a flexible energy carrier and storage medium and can be generated by electrolysis of water. In this research, hydrogen generation is maximized by optimizing the optimal sizing and operating condition of an electrolyzer directly connected to a PV module. The method presented here is based on Particle swarm optimization algorithm (PSO). The hydrogen, in this study, was produced using a proton exchange membrane (PEM) electrolyzer. The required power was supplied by a photovoltaic module rated at 80 watt. In order to optimize Hydrogen generation, the cell number of the electrolyser and its activity must be 9 and 3, respectively. As a result, it is possible to closely match the electrolyzer polarization curve to the curve connecting PV system's maximum power points at different irradiation levels. PSO is a novel method in optimization inspiring from observation of bird flocking and fish schooling. Comparing to other optimization method, not only PSO is more efficient and require lower functions of evaluations, but it leads to better results, as well. Copyright © 2012 by ASME.
Safarian S.,Sharif Energy Research Institute |
Khodaparast P.,Sharif University of Technology |
Kateb M.,University of Tehran
Journal of Solar Energy Engineering, Transactions of the ASME | Year: 2014
To attain an ongoing electricity economy, developing novel widespread electricity supply systems based on diverse energy resources are critically important. Several photovoltaic (PV) technologies exist, which cause various pathways to produce electricity from solar energy. This paper evaluates the competition between three influential solar technologies based on photovoltaic technique to find the optimal pathways for satisfying the electricity demand: (1) multicrystalline silicon; (2) copper, indium, gallium, and selenium (CIGS); and (3) multijunction. Besides the technical factors, there are other effective parameters such as cost, operability, feasibility, and capacity that should be considered when assessing the different pathways as optimal and viable long-term alternatives. To aid this decision-making process, a generic optimization-based model was developed for the long-range energy planning and design of future electricity supply system from solar energy. By applying dynamic programming techniques, the model is capable of identifying the optimal investment strategies and integrated supply system configurations from the many alternatives. The features and capabilities of the model were shown through application to Iran as a case study. Copyright © 2014 by ASME.