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moltames--rahim
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Techno-economic analysis of a modified concentrating photovoltaic/organic Rankine cycle system
, Article International Journal of Ambient Energy ; 17 February , 2020 ; Roshandel, R ; Sharif University of Technology
Taylor and Francis Ltd
2020
Abstract
The combination of concentrating photovoltaic (CPV) and organic Rankine cycle (ORC) systems not only leads to a reduction of photovoltaic (PV) operating temperature, but also leads to an additional electric power production. Increase in the temperature of the PV decreases its operating efficiency, while increases the ORC efficiency. Therefore, there is an optimum temperature in which the total electricity produced by the combined system will be maximum. In this study, a modified CPV/ORC system is simulated and the optimum operating temperature of the PV panel is determined for different PV efficiencies. The most striking result is that increase in the PV nominal efficiency will result in the...
Techno-economic analysis of a modified concentrating photovoltaic/organic Rankine cycle system
, Article International Journal of Ambient Energy ; Volume 43, Issue 1 , 2022 , Pages 2026-2038 ; 01430750 (ISSN) ; Roshandel, R ; Sharif University of Technology
Taylor and Francis Ltd
2022
Abstract
The combination of concentrating photovoltaic (CPV) and organic Rankine cycle (ORC) systems not only leads to a reduction of photovoltaic (PV) operating temperature, but also leads to an additional electric power production. Increase in the temperature of the PV decreases its operating efficiency, while increases the ORC efficiency. Therefore, there is an optimum temperature in which the total electricity produced by the combined system will be maximum. In this study, a modified CPV/ORC system is simulated and the optimum operating temperature of the PV panel is determined for different PV efficiencies. The most striking result is that increase in the PV nominal efficiency will result in the...
Simulation and Techno–Economical Analysis of an Improved Integrated Concentrated Photovoltaic/Organic Rankine Cycle System
, M.Sc. Thesis Sharif University of Technology ; Roshandel, Ramin (Supervisor)
Abstract
The combination of photovoltaic technology and Organic Rankine Cycle reduces the temperature of the solar panel and, on the other hand, generates separate electricity from excess heat. The reason for the use of the Organic Rankine Cycle is the low temperature of the heat source. It is not economical to use other cycles like steam Rankine cycle in low-temperature heat sources. To maximize the plant factor of the Organic Rankine cycle system, especially when there is not enough solar radiation, it is possible to utilize the flue gas heat recovery in office buildings and reduce the cost of electricity generation. In this project, the simulation of this system is carried out for the Energy...
Thermoeconomic analysis and optimization of a solar micro CCHP by using TLBO algorithm for domestic application
, Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Volume 42, Issue 14 , 2020 , Pages 1747-1761 ; Assareh, E ; Moltames, R ; Sharif University of Technology
Taylor and Francis Inc
2020
Abstract
In the present study, a micro solar Combined Cooling, Heating and Power (CCHP) system based on Organic Rankine Cycle (ORC) is thermodynamically and exergoeconomically investigated. Adding a storage tank will lead to the sustainable supply of energy for summer and winter seasons. The model of conservation of energy, conservation of mass, and conservation of linear momentum are applied in order to energy analysis, while a model based on the first and the second laws of thermodynamics are used to exergy analysis. Determining the effective parameters of the system efficiency, including turbine input pressure, turbine inlet temperature, turbine output pressure, and evaporator temperature leads to...
Exergy analysis and thermodynamic optimisation of a steam power plant-based Rankine cycle system using intelligent optimisation algorithms
, Article Australian Journal of Mechanical Engineering ; 2019 ; 14484846 (ISSN) ; Assareh, E ; Moltames, R ; Sharif University of Technology
Taylor and Francis Ltd
2019
Abstract
In this paper, exergy analysis of a steam power plant located in southern Iran named Zarand power plant has been studied. In order to optimize the performance of the Rankine cycle and achieve higher exergy efficiency, several parameters have been considered as decision variables. Knowing that there is the ability to change some of the parameters in the specific range in the process of electricity production in power plant, temperature and output pressure of the boiler and output pressure of four steps of extraction turbine have been selected as six decision variables. Also, exergy efficiency has been considered as the objective function. For this purpose, the exergy efficiency of the system...
Thermo-economic analysis and multi-objective optimization of a solar dish Stirling engine
, Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; 2020 ; Assareh, E ; Moltames, R ; Jafarinejad, T ; Sharif University of Technology
Bellwether Publishing, Ltd
2020
Abstract
Stirling engines operate in a variety of temperatures and the electric power production via dish Stirling systems could be considered as an appropriate alternative for high-temperature solar concentrator energy harvesting systems. To this end, by performing various studies and analyses on the engine, Stirling cycle, and heat exchangers while utilizing the solar energy as the input thermal energy of the Stirling engine, parameters with the highest effect on the output power and engine stability are detected and considered as optimization variables. In this case, output power, thermal efficiency, and economic evaluation are taken to be the three suitable objective functions for multi-objective...
Thermo-economic analysis and multi-objective optimization of a solar dish Stirling engine
, Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Volume 43, Issue 22 , 2021 , Pages 2861-2877 ; 15567036 (ISSN) ; Assareh, E ; Moltames, R ; Jafarinejad, T ; Sharif University of Technology
Taylor and Francis Ltd
2021
Abstract
Stirling engines operate in a variety of temperatures and the electric power production via dish Stirling systems could be considered as an appropriate alternative for high-temperature solar concentrator energy harvesting systems. To this end, by performing various studies and analyses on the engine, Stirling cycle, and heat exchangers while utilizing the solar energy as the input thermal energy of the Stirling engine, parameters with the highest effect on the output power and engine stability are detected and considered as optimization variables. In this case, output power, thermal efficiency, and economic evaluation are taken to be the three suitable objective functions for multi-objective...
Investigation of Impurities and Structural Defects in Graphene
, M.Sc. Thesis Sharif University of Technology ; Faez, Rahim (Supervisor)
Abstract
In this thesis the effects of impurities and different defects on electrical and magnetic properties of monolayer and bilayer graphene is investigated. Calculations are performed using density function theory. Alloying monolayer graphene with boron and nitrogen the energy gaps of 0.7 and 0.6 eV are obtained, respectively. Moreover, we show that BN is a good candidate for opening the band gap in graphene. Alloying monolayer graphene with BN the energy gap of 1.2 eV is obtained. Another way of opening band gap is to somehow break the symmetry between layers of the bilayer graphene. By alloying one layers of bilayer graphene with B, N or B-N, although the symmetry of layers is broken, each...
Simulation of Graphene Nanoribbon based Photodetector
, M.Sc. Thesis Sharif University of Technology ; Faez, Rahim (Supervisor)
Abstract
In this work, we have simulated graphene nanoribbon based photodetector and impact of changing the width, and Boron-Nitride doping and Stone-Wales defects on the optical properties of GNR has study. The energy band structure of GNR with nearest-neighbor approximation in a tight binding model calculated. To correspond with experiment and accuracy, we need to consider the impact of third nearest neighbors and edge bond relaxation. By Using the band structure, we calculated joint density of state and optical matrix elements and obtain inter band selection rule for A-GNR and Z-GNR. Then, using the Fermi’s golden rule, we investigate optical properties of GNR such as optical conductivity and...
A Simulation Study of Graphene Nanoribbon Field Effect Transistor
, M.Sc. Thesis Sharif University of Technology ; Faez, Rahim (Supervisor)
Abstract
In this thesis, a field effect transistor (FET) using armchair graphene nanoribbon as the channel is simulated, and the effects of changing nanoribbon width and length, as well as adding defects, are also studied. To obtain the Hamiltonian matrix and the energy band structure of graphene nanoribbon, tight binding method is used in which the first and third neighbor approximation is considered. Also, to maximize accuracy, we also considered the edge bond reconstruction. To obtain the transport characteristics of the transistor, such as the transmission coefficient and the density of states (DOS), Poisson and Schrodinger equations are solved self-consistently. We used the nonequilibrium...
Design of Graphene Spintronic Devices
, M.Sc. Thesis Sharif University of Technology ; Faez, Rahim (Supervisor)
Abstract
Magnetization have an important role in spintronic devices based on graphene. In this study the effect of stone-wales and vacancy defect on electrical and magnetic properties of zigzag and armchair graphene nanoribbons were investigated. Calculations are performed using tight-binding and hubard model combining with Green's function techniques. When the balance between A and B sub-lattices gets disturbed, magnetization will be appeared. In stone-wales defect we have local magnetization because of changing the position of sub-lattices and the total magnetization is zero. In addition the stone-wales defect can change and modify the band structures and band gaps. Vacancy of carbon atom in...
Simulation of Organic Solar Cells
, M.Sc. Thesis Sharif University of Technology ; Faez، Rahim (Supervisor)
Abstract
Solar cells are one of the most promising clean and readily available energy sources. Organic solar cells as a new generation of solar cells, have attracted strong attention in recent years, due to the advantages of flexibility, thinness, and simple manufacturing process. This work focuses on the electrical processes in organic solar cells and approaches for enhancing the efficiency of solar cell by employing two-dimensional drift-diffusion model. At the first step. We investigate the role of different parameters such as mobility (considering different recombination mechanisms), active layer thickness, light intensity, barrier injections and energetic disorder on the performance of single...
Design and Simulation of Panchromatic Organic Photodetector
, M.Sc. Thesis Sharif University of Technology ; Faez, Rahim (Supervisor)
Abstract
Organic photodetectrors(OPD) are new generation of photodetectors that use of organic materials to convert optical signal to electrical current. Organic photodetectors in recent decade have witnessed significant improvements and many recent research allocated to this photodetectors. This OPD’s have important application so that the inorganic photodetectors have some problems in that application , for example: wide area imagination , biomedical sensors , flexible application and . . . .This work focus on the design and simulation of a panchromatic photodetector that use of new material and have high bandwidth and low dark current. One of application of this OPD is to use in optical...
Simulation and Comparative Study of Tunneling FETs Based on Graphene Nanoribbon and Phosphorene Monolayer
, M.Sc. Thesis Sharif University of Technology ; Faez, Rahim (Supervisor)
Abstract
In this thesis, we simulate and investigate two transistors which both have tunneling FET (TFET) structure but the channel in the first one is graphene nanoribbon (GNR) and in the second one is a monolayer of phosphorene (PML). To describe the quantum systems of the transistors, we use the tight binding method and its models for the channel materials. In case of the PML TFET, based on the behavior of the phosphorene nanoribbon in different widths, we obtain a proper amount for the width to model the infinite-width channel. To extract the channel quantum transport, the Schrodinger-Poisson equations are self-consistently solved. In the next step, we simulate the GNR TFET and present the...
Modeling and Simulation of a High Power Photoconductive Semiconductor Switch (PCSS)
, M.Sc. Thesis Sharif University of Technology ; Faez, Rahim (Supervisor)
Abstract
There are a wide variety of light-triggered switches. Photoconductive semiconductor switches (PCSSs) have been investigated intensively for many applications owing to their unique advantages over other switches. The advantages of PCSSs make them a perfect choice for many important applications where high switching accuracy and high-power capability are required. Photoconductive switches are fabricated from a variety of semiconductors, including silicon carbide (SiC), gallium arsenide (GaAs) and gallium nitride (GaN). In Photoconductive semiconductor switches (PCSSs) the switching mechanism is initiated by optical illumination and laser source controls the flow of current. In the off or...
Simulation and Analysis Graphene Based Bio-chemical Sensor Using Localized Surface Plasmon Resonance
, M.Sc. Thesis Sharif University of Technology ; Faez, Rahim (Supervisor)
Abstract
One of the different sensing techniques for biosensors is based on surface plasmon resonance which provides high reliability and efficiency. In this project working operating principles of biosensors based on surface plasmon resonance will be examined. For investigation of sensing meachanism we assume that there an array consisting of alternating graphen ribbons which by applying light leads to an effective magnetic field coupling to the localized surface plasmon. The numerical calculations are based on the exact solution of Maxwell's equation using Fuorier Model Method and Matlab coding. In these calculations, the coefficients of transmission, reflection and absorption of light versus...
Ferromagnetic Single Electron Transistor
, M.Sc. Thesis Sharif University of Technology ; Faez, Rahim (Supervisor)
Abstract
This thesis completely introduses ferromagnetic single electron transistor while that identifies the application and types of the transistor.Master equation is used for simulationing of the transistor. This simulation is divided to two general sections.In the first section proposed thermal equilibrium the normal island and The two spin subsystems , however, are in thermal equilibrium and quantized nature of energy spectrum of a small central electrode and fluctuations in the spin accumulation were ignored , however, we simplify the problem and assume that the charging energy are independent of the electron distribution, and number of electrons in the normal island. ،hat tunnel rates can be...
Quantum Dot Infrared Photodetector
, M.Sc. Thesis Sharif University of Technology ; Faez, Rahim (Supervisor)
Abstract
Conventionally all objects radiate most of its energy in the from of infrared waves, therefore, infrared photodetectors for detecting objects is important and more study is done on improve the detecting parameters. The proposed structures are developed from bulk to quantum well and quantum dots in recently years. In this work at reason insensitivity to incident light polarization, flexible operation wavelength, high operation temperature, inherent photovoltaic effect, low capture probability we study the structure of quantum dot infrared photodetectors and then for improve the detecting parameters structure of two layers quantum dot separated with a layer thin barrier (bilayer). And then a...
Intelligent based trajectory planning in Terrain Following flight
, Article 25th Congress of the International Council of the Aeronautical Sciences 2006, Hamburg, 3 September 2006 through 8 September 2006 ; Volume 5 , 2006 , Pages 3169-3175 ; Malaek, S. M ; Sharif University of Technology
Curran Associates Inc
2006
Abstract
A novel approach in Terrain Following/Terrain Avoidance (TF/TA) flight is proposed that facilitates flying over unknown terrains. Intelligency is implemented using fuzzy decision making tools. This method can be used in offline design in trajectory planning which has wide applications in TF/TA. A relationship b etween slope of terrain and aircraft height with speed of aircraft is constructed by fuzzy approach
Quantum Well Solar Cell
, M.Sc. Thesis Sharif University of Technology ; Faez, Rahim (Supervisor)
Abstract
In this thesis, the goal is to improve the efficiency of quantum and solar cell. The effect of quantum wells was simulated by Silvaco. Initially, the quantum well has been adjusted to a cell junction GaAs. Then, using quantum wells in cell junction towing and three, improving short-circuit, the returns will be 53.79% and 54.33%. This efficiency is about 10% more than the triple-junction solar cells. To improve the efficiency effects of layer thicknesses, parameters, and the number of quantum wells were studied.Tandem cell is 〖In〗_0.51 〖Ga〗_0.49 P/GaAs, and triple is 〖In〗_0.51 〖Ga〗_0.49 P/GaAs/〖In〗_0.28 〖Ga〗_0.72 As. By adjusting the quantum well and sandwiching the well layers staggered by...