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Two strategies for multi-objective optimisation of solid oxide fuel cell stacks
, Article International Journal of Sustainable Energy ; Vol. 33, issue. 4 , 2014 , p. 854-868 ; Behzadi Forough, A ; Sharif University of Technology
2014
Abstract
This paper focuses on multi-objective optimisation (MOO) to optimise the planar solid oxide fuel cell (SOFC) stacks performance using a genetic algorithm. MOO problem does not have a single solution, but a complete Pareto curve, which involves the optional representation of possible compromise solutions. Here, two pairs of different objectives are considered as distinguished strategies. Optimisation of the first strategy predicts a maximum power output of 108.33 kW at a breakeven per-unit energy cost of 0.51 $/kWh and minimum breakeven per-unit energy cost of 0.30 $/kWh at a power of 42.18 kW. In the second strategy, maximum efficiency of 63.93%at a breakeven per-unit energy cost of 0.42...
Multi objective optimization of solid oxide fuel cell stacks considering parameter effects: Fuel utilization and hydrogen cost
, Article Journal of Renewable and Sustainable Energy ; Volume 5, Issue 5 , 2013 ; 19417012 (ISSN) ; Roshandel, R ; Sharif University of Technology
2013
Abstract
In the context of stationary power generation, fuel cell based systems are being predicted as a valuable option to tabernacle the thermodynamic cycle based power plants. In this paper, multi objective optimization approach is used to optimize the planer solid oxide fuel cell (SOFC) stacks performance using genetic algorithm technique. Multi objective optimization generates the most attractive operating conditions of a SOFC system. This allows performing the optimization of the system regarding to two different objectives. Two pairs of different objectives are considered in this paper as distinguished strategies. In the first strategy, minimization of the breakeven per-unit energy cost...
Design and operation optimization of an internal reforming solid oxide fuel cell integrated system based on multi objective approach
, Article Applied Thermal Engineering ; Volume 114 , 2017 , Pages 561-572 ; 13594311 (ISSN) ; Roshandel, R ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
The interaction between design parameters and operation variables is a complex problem that affects system techno-economic performance. The aim of this paper is to optimize the design and operation of an SOFC/MGT integrated system. The problem consists of design and operation optimization of an integrated SOFC/MGT system. Decision variables including design parameters (number of SOFC cells) as well as the operation parameters (air pressure ratio, methane and air flow rates). The multi objective approach using genetic algorithm is applied considering two pairs of proposed objectives: (1) maximization of output power and minimization of the electricity cost and (2) maximization of system...
Multi objective receding horizon optimization for optimal scheduling of hybrid renewable energy system
, Article Energy and Buildings ; Volume 150 , 2017 , Pages 583-597 ; 03787788 (ISSN) ; Roshandel, R ; Sharif University of Technology
2017
Abstract
In this paper, a methodology for energy management system (EMS) based on the multi-objective receding horizon optimization (MO-RHO) is presented to find the optimal scheduling of hybrid renewable energy system (HRES). The proposed HRES which is experimentally installed in educational building comprising the PV panels, wind turbine, battery bank and diesel generator as the backup system. The data acquisition system provides input profiles for receding horizon optimizer. A mixed-integer convex programing technique is used to achieve the optimal operation regarding to two conflicting operation objectives including diesel fuel cost and battery wear cost. The Pareto frontiers are presented to...
Lifetime optimization framework for a hybrid renewable energy system based on receding horizon optimization
, Article Energy ; Volume 150 , 1 May , 2018 , Pages 617-630 ; 03605442 (ISSN) ; Roshandel, R ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
In this work, a novel convex sequence framework for real-time receding horizon operation optimization of a hybrid renewable energy system integrated with optimal sizing is presented to increase the penetration rate of renewable energy in supplying the demand. The proposed framework optimizes the entire lifetime cost of a system consisting of two main steps which are 1) design & installation and 2) operation as two sequence modules. This framework is applied to a hybrid renewable energy system which includes PV, wind turbine, batteries and a diesel generator. In the operation optimization, receding horizon strategy is used to optimize the operation schedule. Mixed integer convex programming...
Multi Objective Optimization of a Solid Oxide Fuel Cell/Micro Gas Turbine Integrated System
, M.Sc. Thesis Sharif University of Technology ; Roshandel, Ramin (Supervisor)
Abstract
In this project, multi objective optimization (MOO) approach is used to optimize the SOFC/MGT integrated system performance in two strategies. In order to improve the performance and increase of Micro Gas Turbine (MGT) efficiency, it can be combined with Solid Oxide Fuel Cell (SOFC) which it has high operating temperature.The multi-objective optimisation method used allows to generate Pareto curves that represent the trade-off between conflicting thermo-economic objectives of SOFC/MGT integrated system, like, electrical efficiency, output power and electricity cost. The results of the thermo-economic optimization offer a basis for decision making and engineering improvement. SOFC capacity...
A Framework for Lifetime Management and Optimization of Hybrid Renewable Energy System Based on Integrated Methodology of Design and Energy Management System (Operation). Case study: Integrated Photovoltaic/wind Turbine System
, Ph.D. Dissertation Sharif University of Technology ; Roshandel, Ramin (Supervisor)
Abstract
In this project, a comprehensive methodology is developed to present the lifetime management and optimization framework for hybrid renewable energy systems. The main purpose of this work is to minimize the lifetime cost and improve the system reliability based on the interaction between different optimization levels related to different steps in the system lifetime. The proposed methodology is generally presented by providing a connection between the three specified optimization levels: 1) Planning: including design and long-term optimization models which is performed before system operation, 2) Real-time operation: By employing the receding horizon optimization which is applied from the...
Single event upset immune latch circuit design using C-element
, Article Proceedings of International Conference on ASIC, 25 October 2011 through 28 October 2011, Xiamen ; 2011 , Pages 252-255 ; 21627541 (ISSN) ; 9781612841908 (ISBN) ; Tabandeh, M ; Sharif University of Technology
2011
Abstract
Downscaling trend in CMOS technology on the one hand and reducing supply voltage of the circuits on the other hand, make devices more susceptive to soft errors such as SEU. Latch circuits are prone to be affected by SEUs. In this article, we propose a new circuit design of latch using redundancy with the aim of immunity against SEUs. According to simulation results, our design not only guaranties full immunity, but also has the advantage of occupying less area and consuming much less power and performance penalty in comparison with other SEU immune latches. The simulation results show that our solution has 65.76% reduction in power and about 50.65% reduction in propagation delay in...
Azote Removal in Submerged Fixed Bed Reactor by Modified Ludzack-Ettinger (MLE)Process
, M.Sc. Thesis Sharif University of Technology ; Borgheei, Mahdi (Supervisor)
Abstract
Nitrogen compounds are becoming increasingly important in wastewater management, because of the many effects that nitrogenous material can have on the environment that need nitrogen removal. In this study, the performance of a submerged fixed bed reactor in nitrogen removal, constructed two anoxic and aerobic sections under Modified Ludzack-Ettinger process was investigated. Laboratory experiments were conducted at a constant COD concentration of 350 mg/lit, hydraulic retention times of 8, 12 and 18 hours and influent ammonia loading rate between 0.128 and 0.955 g NH3/m2.day. Nitrogen removal efficiency was obtained between 80.4 and 97.3%, and COD removal efficiency was achieved between 88.9...
Soft error rate estimation for combinational logic in presence of single event multiple transients
, Article Journal of Circuits, Systems and Computers ; Vol. 23, issue. 6 , 2014 ; Tabandeh, M ; Fazeli, M ; Sharif University of Technology
2014
Abstract
Fast and accurate estimation of soft error rate in VLSI circuits is an essential step in a soft error tolerant ASIC design. In order to have a cost effective protection against radiation effects in combinational logics, an accurate and fast method for identification of most susceptive gates and paths is needed. In this paper, an efficient, fast and accurate method for soft error propagation probability (SEPP) estimation is presented and its performance is evaluated. This method takes into account all three masking factors in multi cycles. It also considers multiple event transients as a new challenge in soft error tolerant VLSI circuit design. Compared with Monte Carlo (MC) simulation-based...
Low cost soft error hardened latch designs for nano-scale CMOS technology in presence of process variation
, Article Microelectronics Reliability ; Volume 53, Issue 6 , June , 2013 , Pages 912-924 ; 00262714 (ISSN) ; Tabandeh, M ; Fazeli, M ; Sharif University of Technology
2013
Abstract
In this paper, two Low cost and Soft Error Hardened latches (referred to as LSEH1 and LSEH2) are proposed and evaluated. The proposed latches are fully SEU immune, i.e. they are capable of tolerating all particle strikes to any of their nodes. Moreover, they can mask Single Event Transients (SETs) occurring in combinational logics and reaching the input of the latches. We have compared our SEU/SET-tolerant latches with some well-known previously proposed soft error tolerant latches. To evaluate the proposed latches, we have done a set of SPICE simulations. The simulation results trough comparisons with other hardened latches reveal that the proposed latches not only have more robustness but...
Single Event Multiple Upset (SEMU) tolerant latch designs in presence of process and temperature variations
, Article Journal of Circuits, Systems and Computers ; Volume 24, Issue 1 , January , 2015 ; 02181266 (ISSN) ; Tabandeh, M ; Fazeli, M ; Sharif University of Technology
World Scientific Publishing Co. Pte Ltd
2015
Abstract
In this paper, we propose two novel soft error tolerant latch circuits namely HRPU and HRUT. The proposed latches are both capable of fully tolerating single event upsets (SEUs). Also, they have the ability of enduring single event multiple upsets (SEMUs). Our simulation results show that, both of our HRPU and HRUT latches have higher robustness against SEMUs as compared with other recently proposed radiation hardened latches. We have also explored the effects of process and temperature variations on different design parameters such as delay and power consumption of our proposed latches and other leading SEU tolerant latches. Our simulation results also show that, compared with the reference...
Quantum discrepancy: A non-commutative version of combinatorial discrepancy
, Article Electronic Journal of Combinatorics ; Volume 27, Issue 2 , 2020 , Pages 1-29 ; Rajaee, M ; Rajaei, A ; Sharif University of Technology
Australian National University
2020
Abstract
In this paper, we introduce a notion of quantum discrepancy, a non-commutative version of combinatorial discrepancy which is defined for projection systems, i.e. finite sets of orthogonal projections, as non-commutative counterparts of set systems. We show that besides its natural algebraic formulation, quantum discrepancy, when restricted to set systems, has a probabilistic interpretation in terms of determinantal processes. Determinantal processes are a family of point processes with a rich algebraic structure. A common feature of this family is the local repulsive behavior of points. Alishahi and Zamani (2015) exploit this repelling property to construct low-discrepancy point...
Sliding-mode control of z-source inverter
, Article 34th Annual Conference of the IEEE Industrial Electronics Society, IECON 2008, Orlando, FL, 10 November 2008 through 13 November 2008 ; 2008 , Pages 947-952 ; 9781424417667 (ISBN) ; Kaboli, S ; Emadi, A ; Sharif University of Technology
IEEE Computer Society
2008
Abstract
In this paper, sliding-mode control (SMC) is applied to a z-source converter to control output dc voltage of impedance network. The converter is assumed working in continuous conduction mode (CCM). First a comprehensive review of the literature for z-source inverter (ZSI) and use of sliding mode control in switched converters are performed. The procedure of SMC design used in ZSI is presented. The simulations for the application of SMC in z-source inverter are made and the results are illustrated. The results verify the effectiveness and robustness of the controller. © 2008 IEEE
A new approach of optimal appliance scheduling for peak load reduction of an off-grid residential building
, Article Journal of Building Performance Simulation ; Volume 16, Issue 2 , 2023 , Pages 131-143 ; 19401493 (ISSN) ; Haddadi, M ; Nord, N ; Sharif University of Technology
Taylor and Francis Ltd
2023
Abstract
Demand for electricity, due to the fast growth in urbanization and industrialization, is on the rapid rise. Load shift is a basic method for demand side management (DSM) that can be used by the central controller in buildings and can lead to the maximum use of renewable energy sources, maximum economic benefits, and reduction of peak demand. This paper proposes an algorithm for shifting the flexible loads of four selected appliances with respect to boundary limits for each appliance. A standalone four-story building with different number of occupants is considered to evaluate this algorithm. The algorithm was trained on Richardson model to minimize two objectives including aggregated demand,...
Analysis of Circular Slot Antenna on a Ferrite Substrate
, M.Sc. Thesis Sharif University of Technology ; Rajaei, Behzad (Supervisor)
Abstract
Circular polarization (CP) is one of the common polarization types used in wireless systems for frequency identification (RFID), global positioning (GPS) and wireless local area networks (WLAN), since it can provide greater flexibility in orientation angle between transmitter and receiver, and better mobility and weather penetration than the linearly polarized antennas. Magnetic permeability in ferrites can be tuned by external magnetic field ; So ferrites can be good candidates for new reconfigurable CP antenna technology. In this project, we will consider circularly polarized slot antenna with a wide axial ratio beamwidth that consists of a normally magnetized ferrite substrate mounted...
Separating and Bi-separating Maps and Their Relation to Banach-Stone Theorem
, M.Sc. Thesis Sharif University of Technology ; Ranjbar Motlagh, Alireza (Supervisor)
Abstract
Let C(S) and C(T) denote the sup-normed Banach spaces of real or complex-valued continuous functions on the compact Hausdorff spaces S and T, respectively. A linear map H:C(T)→C(S) is called separating if, for x,y∈C(T), xy≡0 implies HxHy≡0. In the second chapter of this thesis, we will show that any continuous separating map is a continuous multiple of a composition map. Moreover, it will be proved that any linear separating isomorphism of C(T) onto C(S) is continuous. We will also define separating and biseparating maps on the rings of continuous functions equipped with the compact-open topology. In addition, vector-valued separating maps will be investigated. For example, assume that C(T)...
Solving Congestion Pricing and Network Design Problem Simultaneously for Conventional and Automated Vehicles
, M.Sc. Thesis Sharif University of Technology ; Zokaei Aashtiani, Hedayat (Supervisor)
Abstract
In this dissertation, transportation networks with two classes of vehicles, including conventional vehicles and autonomous vehicles, have been studied. Four problems, including traffic assignment problem with two classes, congestion pricing problem for conventional vehicles, network design problem for autonomous vehicles, and simultaneous congestion pricing and network design problem, have been modeled and algorithms to solve them are presented. In this study, a dynamic penalty function algorithm is used to solve the congestion pricing problem, and a heuristic algorithm is used to solve the network design problem. Besides, the two-class traffic assignment problem is solved using the...
Simulation and Optimization of Downhole Pumps with Focus on IOR Application in Iranian Fields
, M.Sc. Thesis Sharif University of Technology ; Shad, Saeed (Supervisor)
Abstract
Three-dimensional (3D) computational fluid dynamics (CFD) was used in this study to investigate single and multi phase flow behavior related to three stages of ESP pump. Compared to experimental measurements, the numerical prediction for single phase flow of water is matched very well. Furthermore, the effects of viscosity and pump rotational speed for oil were investigated and the results show that by increasing oil viscosity and decreasing rotational speed, the pump head and efficiency reduced. ESP performance under two phase oil-methane flow and the effect of oil viscosity, rotational speed, intake pressure, gas bubble diameter, oil rate and gas volume fraction were studied. ESP boosting...
Developing a New Mechanism for Managing Technical Issues of Energy Transactions in Transactive Energy Market
, M.Sc. Thesis Sharif University of Technology ; Fotuhi Firuzabad, Mahmud (Supervisor)
Abstract
Distribution power systems are undergoing a fundamental transition with the introduction of microgrids (MGs) and proliferation of renewable energy sources inspired mainly by privacy and environmental concerns. In this regard, energy management methods employed by utilities should take into account the intermittent nature of RESs power production while coping with the independent operation of MGs. Transactive energy (TE) is an emerging concept which utilizes economic-based mechanisms to facilitate the dynamic and decentralized management of active agents of the system. However, the energy transactions between transactive agents could have adverse impacts on the technical aspect of the system...