Search for: energy-conservation
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    Building energy modeling with OpenStudio : a practical guide for students

    , Book Brackney, Larry ; Parker, Andrew ; Macumber, Daniel
    Springer International Publishing AG  2018

    An innovative design and cost optimization of a trigeneration (combined cooling, heating and power) system

    , Article International Journal of Environmental Research ; Volume 8, Issue 4 , 2014 , Pages 971-978 ; ISSN: 17356865 Abbaspour, M ; Saraei, A. R ; Sharif University of Technology
    Load management and cost optimization are among the important factors in trigeneration systems and combined cooling, heating and power (CCHP) systems. In this study, an innovative CCHP system uses a gas turbine as the prime mover and has a heat recovery steam generator (HRSG) in addition to an auxiliary boiler, electric and absorption chillers. The system is tied with the bulk electric grid; to export and sell excess power or import power when necessary. This study analyzes load management and cost optimization of CCHP systems. A heuristic strategy to optimize the total energy cost is then presented. The optimal size of CCHP is determined from the study results. This paper proposes a model... 

    Transient and stability analysis in single-phase natural circulation

    , Article Annals of Nuclear Energy ; Volume 31, Issue 10 , 2004 , Pages 1177-1198 ; 03064549 (ISSN) Mousavian, S. K ; Misale, M ; D'Auria, F ; Salehi, M. A ; Sharif University of Technology
    This paper presents the mathematical modeling of single-phase natural circulation of the University of Genoa's rectangular loop (LOOP#1) by a computer program and using RELAP5 system code. The mass, momentum and energy conservation equations in transient form were solved numerically using the finite difference method. One-dimensional linear stability analysis was performed for the single-phase natural circulation loop and the numerical perturbation technique was used in this analysis. The Nyquist criterion was employed to find the stability map of the LOOP#1. The obtained transient results using the first order upwind scheme of the fluid temperatures in various sectors of the LOOP#1 are... 

    Finite volume discretization of flow in porous media by the MATLAB system

    , Article Scientia Iranica ; Volume 11, Issue 1-2 , 2004 , Pages 146-152 ; 10263098 (ISSN) Shamsai, A ; Vosoughifar, H. R ; Sharif University of Technology
    Sharif University of Technology  2004
    In this paper, a finite volume scheme is used to discretize flow in porous media. A numerical method for treating advection-dominated contaminant transport for flow of groundwater is described. This system combines the advantages of numerical discretization and the finite volume method (like local mass conservation). The equations are dicretized using a finite volume approach. The resulting nonlinear differential system is integrated in time using a solver. The conservation of energy (convection-diffusion) equation is solved using a special method for reducing the oscillation induced by the standard finite volume method. Consequently, a mathematical model for multi-component flow transport... 

    Energy Savings in the Urban Electrified Railway using Onboard Storage Systems Energy Savings in the Urban Electrified Railway Using Onboard Storage Systems

    , M.Sc. Thesis Sharif University of Technology Hanifi, Mahmood (Author) ; Zolghadri, Mohammad Reza (Supervisor)
    Given the high rate of energy dissipation in electric urban rail lines, methods of saving energy in these systems have become a topic of interest. The use of energy saving equipment to save the energy wasted in braking (Because of the diode rectifier, thermal energy is usually wasted and is not reversible) can play an important role in reducing the energy loss. The role of energy storage equipment, from other aspects such as voltage regulation and increasing the system reliability is also remarkable. In this thesis, the various possible methods for saving energy in the Metro system are expressed.
    The various types of storage devices with increased reuse of braking energy which is the... 

    Numerical Investigation of Various Parameters Influence in Atrium Efficiency Improvements for Building’s Natural Ventilation

    , M.Sc. Thesis Sharif University of Technology Farzan, Shahin (Author) ; Moosavi, Ali (Supervisor)
    In order to improve the efficiency of atriums, effective parameters in ventilation and acceleration of airflow are numerous. Nevertheless, parameters such as shape and height of atrium, geometry of the inlet and outlets, opening areas and the presence of heat sources in each store play a vital role. In structures higher than one floor, there is no significant airflow in the upper floors and the ventilation of atrium is unpleasant for residents. Air movement in the building is done by buoyancy-driven force and hot air upward movement due to pressure differences.This study attempts to improve the natural ventilation performance with changing mentioned parameters. So for this purpose, 3D... 

    Energy Conserving in WSNs Using Network Coding

    , M.Sc. Thesis Sharif University of Technology Shahmohamadi, Rahele (Author) ; Manzuri Shalmani, Mohammad Taghi (Supervisor)
    Nowadays Wireless Sensor Networks are used in different situations such as greenhouse, agriculture, military applications and etc. The problem of Wireless Sensor Network is that the sensor nodes have limited the energy source. Besides, the power source of sensor nodes is not rechargeable or replaceable. So, one of the main challenges in Wireless Sensor Networks is saving energy. Whereas, most power is consumed due to transmissions, recently a lot of activities have been accomplished in order to reduce transmission times. In this thesis we have focused on a network coding method which is called Sensecode. Sensecode is a technique for reducing communications between nodes. Actually network... 

    Neighbor Discovery in Smartphone-Based Opportunistic Networks

    , M.Sc. Thesis Sharif University of Technology Hosseini, Mohammad Reza (Author) ; Hemmatyar, Ali Mohammad Afshin (Supervisor)
    In opportunistic networks, the nodes have ad-hoc communications that are formed directly between them, without any infrastructure, and not by any using any other intermediate node. In case that the destination node is not in the same region as the source during the sending of a message, the source will send the message to one or a few of its neighbors so that they can store and carry out the message to the original destination in cooperation known as Store-Carry-Forward Mechanism. Remarkably, in most cases, the devices involving in this type of network, e.g., smartphones, have limited source of energy or they use a battery, there is a need to minimize the energy consumption in the nodes.... 

    Efficient energy-aware routing with redundancy elimination

    , Article IEEE Journal on Selected Areas in Communications ; Volume 33, Issue 12 , 2015 , Pages 2815-2825 ; 07338716 (ISSN) Omidvar, N ; Tsang, D. H. K ; Pakravan, M. R ; Lau, V. K. N ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2015
    Energy-Aware routing is a promising technique for reducing energy consumption in future networks. Under this scheme, traffic loads are aggregated over a subset of the network links, allowing other links to be turned off to save energy. Since the capacity of links is the main limiting constraint in this problem, to further improve energy saving, the idea of using redundancy elimination (RE) in energy-Aware routing has been proposed. As performing RE in routers consumes some energy, it should be specified, which routers should perform RE and which links should be deactivated so that the total energy consumption of the network is minimized. As a result, the problem of energy-Aware routing with... 

    Effect of hydrogen combustion reaction on the dehydrogenation of ethane in a fixed-bed catalytic membrane reactor

    , Article Chinese Journal of Chemical Engineering ; Volume 23, Issue 8 , August , 2015 , Pages 1316-1325 ; 10049541 (ISSN) Hasany, M ; Malakootikhah, M ; Rahmanian, V ; Yaghmaei, S ; Sharif University of Technology
    Chemical Industry Press  2015
    A two-dimensional non-isothermal mathematical model has been developed for the ethane dehydrogenation reaction in a fixed-bed catalytic membrane reactor. Since ethane dehydrogenation is an equilibrium reaction, removal of produced hydrogen by the membrane shifts the thermodynamic equilibrium to ethylene production. For further displacement of the dehydrogenation reaction, oxidative dehydrogenation method has been used. Since ethane dehydrogenation is an endothermic reaction, the energy produced by the oxidative dehydrogenation method is consumed by the dehydrogenation reaction. The results show that the oxidative dehydrogenation method generated a substantial improvement in the reactor... 

    Mean-square performance analysis of the family of selective partial update and selective regressor affine projection algorithms

    , Article Signal Processing ; Volume 90, Issue 1 , 2010 , Pages 197-206 ; 01651684 (ISSN) Esfand Abadi, M. S ; Palangi, H ; Sharif University of Technology
    In this paper we present a general formalism for the establishment and mean-square performance analysis of the family of selective partial update affine projection (SPU-AP), selective regressor affine projection (SR-AP), and selective partial update subband adaptive filter (SPU-SAF) algorithms. This analysis is based on energy conservation arguments and does not need to assume a Gaussian or white distribution for the regressors. We demonstrate through simulations that the results are useful in predicting the performance of these adaptive filter algorithms  

    Motion of a hexagonal pencil on an inclined plane

    , Article American Journal of Physics ; Volume 77, Issue 5 , 2009 , Pages 401-406 ; 00029505 (ISSN) Rezaeezadeh, A ; Sharif University of Technology
    This article discusses a hexagonal prism rolling down an inclined plane, which is easy to realize experimentally and yields results that are consistent with a simple theory. This investigation would make an excellent undergraduate project. © 2009 American Association of Physics Teachers  

    A new sufficient condition for 1-coverage to imply connectivity

    , Article 3rd International Conference on Digital Information Management, ICDIM 2008, London, 13 November 2008 through 16 November 2008 ; January , 2008 , Pages 495-499 ; 9781424429172 (ISBN) Khasteh, H ; Bagheri Shouraki, S ; Kiaei, A. A ; Sharif University of Technology
    An effective approach for energy conservation in wireless sensor networks is scheduling sleep intervals for extraneous nodes while the remaining nodes stay active to provide continuous service. For the sensor network to operate successfully the active nodes must maintain both sensing coverage and network connectivity, It proved before if the communication range of nodes is at least twice the sensing range, complete coverage of a convex area implies connectivity among the working set of nodes. In this paper we consider a rectangular region A =a *b , such that Rs ≤ a, Rs ≤ b where Rs is the sensing range of nodes. and put a constraint on minimum allowed distance between nodes( Rs ). according... 

    Model for optimizing energy efficiency through controlling speed and gear ratio

    , Article Energy Efficiency ; Volume 1, Issue 1 , 2008 , Pages 65-76 ; 1570646X (ISSN) Saboohi, Y ; Farzaneh, H ; Sharif University of Technology
    Specific fuel consumption of vehicles has been improved through technical changes in the last three decades. There has been little study of the impact of behavioral aspects on the specific fuel consumption of vehicles. Analytical tools developed recently have included options for quantifying the specific fuel consumption in certain predefined driving cycles. Empirical studies have shown that real driving cycles are different from predefined ones. It has also been observed that optimal coordination of both speed of vehicle and gear ratio are detrimental to the improved performance of a vehicle. Previous studies have only considered the vehicle speed as the explanatory parameter, and gear... 

    Development of energy management system for A parallel hybrid electric vehicle using fuzzy logic

    , Article 8th Biennial ASME Conference on Engineering Systems Design and Analysis, ESDA2006, Torino, 4 July 2006 through 7 July 2006 ; Volume 2006 , 2006 ; 0791837793 (ISBN); 9780791837795 (ISBN) Fazeli, A. M ; Nabi, A ; Salmasi, F. R ; Amiri, M ; Sharif University of Technology
    In this paper a fuzzy power controller for a parallel hybrid passenger car is developed in order to minimize its fuel consumption and optimize its components efficiencies. This is done by controlling the engine operating points in its optimal region and maintaining the SoC of batteries and electric motor operating point at the highest possible efficiency. Of course the designed control strategy must be able to obey the driver's commands and achieve the PNGV regulations. The controller implemented in this paper is a Mamdani fuzzy logic controller which takes the batteries SoC, electric motor's speed, ICE speed and the total demanded torque as its input variables and gives the ICE torque as... 

    An updated review of the performance of nanofluid-based photovoltaic thermal systems from energy, exergy, economic, and environmental (4E) approaches

    , Article Journal of Cleaner Production ; Volume 282 , 2021 ; 09596526 (ISSN) Salari, A ; Taheri, A ; Farzanehnia, A ; Passandideh fard, M ; Sardarabadi, M ; Sharif University of Technology
    Elsevier Ltd  2021
    One of the most prominent hybrid solar devices is the photovoltaic thermal system (PVTS), which is able to provide simultaneous electricity and thermal energy. The thermal energy is the heat absorbed by the photovoltaic (PV) module and transferred to the attached thermal collector and finally to the heat transfer fluid. Utilizing a proper heat transfer fluid is an effective means to increase in obtained thermal and electrical powers and enhance PV thermal management. Over the past decade, employing nanofluids thanks to their superior thermophysical properties became a proved strategy to improve the efficiency of the PVTS. This paper covers cutting-edge researches on nanofluid-based PVTS via... 

    Non-linear behavior of mass concrete in three-dimensional problems using a smeared crack approach

    , Article Earthquake Engineering and Structural Dynamics ; Volume 34, Issue 3 , 2005 , Pages 247-269 ; 00988847 (ISSN) Mirzabozorg, H ; Ghaemian, M ; Sharif University of Technology
    John Wiley and Sons Ltd  2005
    A smeared crack approach has been proposed to model the static and dynamic behavior of mass concrete in three-dimensional space. The proposed model simulates the tensile fracture on the mass concrete and contains pre-softening behavior, softening initiation, fracture energy conservation and strain rate effects under dynamic loads. The validity of the proposed model has been checked using the available experimental results under static and dynamic loads. The direct and indirect displacement control algorithms have been employed under incremental increasing static loads. It was found that the proposed model gives excellent results and crack profiles when compared with the available data under... 

    Optimal distributed generation allocation in distribution network using Hereford Ranch algorithm

    , Article ICEMS 2005: 8th International Conference on Electrical Machines and Systems, Nanjing, 27 September 2005 through 29 September 2005 ; Volume 2 , 2005 , Pages 916-918 ; 7506274078 (ISBN); 9787506274074 (ISBN) Gandomkar, M ; Vakilian, M ; Ehsan, M ; Sharif University of Technology
    IEEE Computer Society  2005
    The necessity for flexible electric systems, energy saving, loss reducing and environmental impact are providing Impetus to the development of Distributed Generation (DG). DG Includes the application of small generators, scattered throughout a power system, to provide the electric power needed by electrical customer. Such locally distributed generation, has several merits from the viewpoint of environmental restriction and location limitations, as well as transient and voltage stability In the power system. The exact solution of the DG allocation can be obtained by a complete enumeration of all feasible combinations of sites and sizes of DGs In the network. The number of alternatives could... 

    Evaluation of energy recovery and potential of hydrogen production in Iranian natural gas transmission network

    , Article Energy Policy ; Volume 61 , 2013 , Pages 65-77 ; 03014215 (ISSN) Safarian, S ; Saboohi, Y ; Kateb, M ; Sharif University of Technology
    In the natural gas transmission network, from supply points to demand nods there are various technological options that include processing, transportation, conversion and gas distribution. Comprehensive analysis of natural gas network requires evaluation of different chains of gas flow through various levels based on economical and environmental criteria subject to technical and operational constraints such as feasibility, operability and reliability of different alternatives. To aid decision-making process in the sector of natural gas, a generic optimization-based model has been developed for assessing long term energy issues related to planning and design of natural gas supply systems. The... 

    Porous media approach in thermohydraulic analysis of high temperature reactors in pressurized/depressurized cooldown: An improvement

    , Article Progress in Nuclear Energy ; Volume 80 , 2015 , Pages 119-127 ; 01491970 (ISSN) Nouri Borujerdi, A ; Tabatabai Ghomsheh, S. I ; Sharif University of Technology
    Elsevier Ltd  2015
    The current study aims at introducing a 2D and fast-running code for the issues pertinent to design, analysis and safety in modular high temperature reactors. While the porous media approach is only applied to pebble bed type, the analysis in this paper covers both pebble bed and prismatic reactor. A time-dependent mass equation along with energy conservation equation for the cooling gas and a time-dependent energy conservation equation for the solid was solved. Appropriate series of constitutive equations (e.g. heat transfer coefficient, effective heat conductivity of solid, heat transfer coefficient, pressure drop etc.) has been recruited as well. In addition a finite-volume method is...