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    Optimization of MHD generator based combined cycle efficiency

    , Article 2005 ASME Power Conference, Chicago, IL, 5 April 2005 through 7 April 2005 ; Volume PART B , 2005 , Pages 1209-1214 ; 0791841820 (ISBN); 9780791841822 (ISBN) Saidi, M. H ; Rezaei, H. D ; Mozafari, A. A ; Dehkordy, A. J ; ASME Power Division ; Sharif University of Technology
    American Society of Mechanical Engineers  2005
    Abstract
    Energy crisis has directed scientific efforts to increase the efficiency of power generation systems. Thermodynamic optimization of MHD (Magneto Hydrodynamic) generator based combined cycles due to their high operating temperatures may seriously reduce exergy destruction and improve the second law efficiency. In this research a combined cycle, comprising of MHD cycle as topping and gas turbine cycle as bottoming cycle has been simulated and analyzed and its pros and cons have been exposed. The first and second law efficiencies have been estimated from the operating pressures and temperatures of the system. To calculate the second law efficiency, the entropy generation of all components of... 

    Using of Exhaust Gas from Gas Turbine for Conservation of Energy Consumption

    , M.Sc. Thesis Sharif University of Technology Ghanbari, Mahdi (Author) ; Nouri, Ali (Supervisor)
    Abstract
    Nowadays, the use of gas turbines with low capacity have acceptance in large quantity. This type of gas turbines with a capacity of approximately 5-200kW are known as microturbines. This type of turbines due to the existence of limitations on increasing of turbine inlet temperature and compressor pressure ratio has low efficiency compared to the turbine with high capacity. Therefore the use of a recuperator in the cycle is necessary. Optimum design of heat recuperator has important effect on improving of gas turbine cycle efficiency. In this project for optimum design of heat recuperator, the effect of recuperator on gas turbine cycle efficiency is studied. By determining geometric... 

    Investigation of effective parameters on the performance of the helium liquefaction cycle

    , Article International Journal of Heat and Technology ; Volume 37, Issue 4 , 2019 , Pages 1009-1018 ; 03928764 (ISSN) Larijani, M. A ; Eslami, M ; Afshin, H ; Sharif University of Technology
    International Information and Engineering Technology Association  2019
    Abstract
    Due to its unique properties, helium has wide application in different industries and scientific fields, which has turned it into a strategic material. Helium liquefaction plants include wide temperature range from 300 k to 4.2 k, so these plants have high energy consumption. A lot of studies have done to optimize the operation of these cycles. In this research, an exergy analysis is performed for a liquid helium production plant. The optimal performance of 3 and 4 stage cycles is extracted using parametric study and the results are compared with those of Collins dual-expander cycle. The results show that by increasing the number of cooling stages, not only the compressor optimum discharge... 

    Investigation of effective parameters on the performance of the helium liquefaction cycle

    , Article International Journal of Heat and Technology ; Volume 37, Issue 4 , 2019 , Pages 1009-1018 ; 03928764 (ISSN) Larijani, M. A ; Eslami, M ; Afshin, H ; Sharif University of Technology
    International Information and Engineering Technology Association  2019
    Abstract
    Due to its unique properties, helium has wide application in different industries and scientific fields, which has turned it into a strategic material. Helium liquefaction plants include wide temperature range from 300 k to 4.2 k, so these plants have high energy consumption. A lot of studies have done to optimize the operation of these cycles. In this research, an exergy analysis is performed for a liquid helium production plant. The optimal performance of 3 and 4 stage cycles is extracted using parametric study and the results are compared with those of Collins dual-expander cycle. The results show that by increasing the number of cooling stages, not only the compressor optimum discharge... 

    Optimization of a regenerative gas turbine engine with isothermal heat addition with the genetic algorithm

    , Article Proceedings of the ASME Turbo Expo, 8 June 2009 through 12 June 2009, Orlando, FL ; Volume 4 , 2009 , Pages 265-274 ; 9780791848852 (ISBN) Haghighi, E ; Borzou, B ; Ghahremani, A. R ; Shafii, M. B ; Sharif University of Technology
    Abstract
    The use of advanced cycles to take advantage of the gas turbine's thermodynamic characteristics has received increasing attention in recent years. These cycles have been developed for large scale power generation. Due to the powerful abilities of bio-inspired computing techniques such as Genetic Algorithm in locating the optimal (or near optimal) solutions to a given optimization problem, they are widely utilized for determining the parameters of different engineering systems in order to meet the specified performance objectives for a given problem. In order to illustrate the performance of one of these techniques, development and application of it for an engineering problem is presented. In... 

    A recent review of waste heat recovery by Organic Rankine Cycle

    , Article Applied Thermal Engineering ; Volume 143 , 2018 , Pages 660-675 ; 13594311 (ISSN) Mahmoudi, A ; Fazli, M ; Morad, M. R ; Sharif University of Technology
    Elsevier Ltd  2018
    Abstract
    The increment of using fossil fuels has caused many perilous environmental problems such as acid precipitation, global climate change and air pollution. More than 50% of the energy that is used in the world is wasted as heat. Recovering the wasted heat could increase the system efficiency and lead to lower fuel consumption and CO2 production. Organic Rankine cycle (ORC) which is a reliable technology to efficiently convert low and medium temperature heat sources into electricity, has been known as a promising solution to recover the waste heat. There are numerous studies about ORC technology in a wide range of application and condition. The main objective of this paper is to presents a... 

    The role of energy subsidy reform in energy efficiency enhancement: lessons learnt and future potential for iranian industries

    , Article Journal of Cleaner Production ; Volume 197 , 2018 , Pages 542-550 ; 09596526 (ISSN) Barkhordar, Z. A ; Fakouriyan, S ; Sheykhha, S ; Sharif University of Technology
    Abstract
    Significant energy subsidies are believed to be the main factor that has resulted in high energy intensities of Iranian industries. The Subsidy Reform Act of 2010 was directed at modifying energy consumption pattern and fostering energy efficiency enhancement. This study aims at analyzing the effect of energy subsidy reform on promoting energy efficiency in six energy intensive industries of Iran. In order to do so, the energy efficiency practices that have not been adopted after the implementation of the first phase of energy subsidy reform are investigated. Data analysis reveals that if financially interesting investments are determined as those with payback periods less than three years,... 

    A combined cooling and power transcritical CO2 cycle for waste heat recovery from gas turbines

    , Article Thermal Science and Engineering Progress ; Volume 34 , 2022 ; 24519049 (ISSN) Sabzpoushan, S ; Morad, M. R ; Ebrahimi Rahnama, H ; Sharif University of Technology
    Elsevier Ltd  2022
    Abstract
    A transcritical carbon dioxide (T-CO2) cycle is analyzed for waste heat recovery from a gas turbine. The cycle is proposed to produce combined power and cooling using carbon dioxide as a single pure working fluid. Simple, cascade and split cycle configurations are compared for power generation using a recuperator while a low-temperature loop is added for the cascade and split cycles. In a previous report in the literature the power generation part alone was presented for the three configurations and it was concluded that the split cycle can produce the highest power among the three systems. Here, the same configurations are studied combined with a compression refrigeration cooling effect... 

    A micro combined heat and power thermodynamic analysis and optimization

    , Article American Society of Mechanical Engineers, Power Division (Publication) POWER, 13 July 2010 through 15 July 2010, Chicago, IL ; 2010 , Pages 599-605 ; 9780791849354 (ISBN) Gholizadeh, A ; Shafii, M. B ; Saidi, M. H ; Sharif University of Technology
    2010
    Abstract
    In modeling and designing micro combined heat and power cycle most important point is recognition of how the cycle operates based on the first and second laws of thermodynamics simultaneously. Analyzing data obtained from thermodynamic analysis employed to optimize MCHP cycle. The data obtained from prime mover optimization has been used for basic stimulus cycle. Assumptions considered for prime mover optimization has been improved, for example in making optimum operation condition by using genetic algorithms constant pressure combustion chamber was considered. The exact value of downstream and upstream pressure changes in the combustion chamber reaction has been obtained. After extraction... 

    Second law based analysis of supplementary firing effects on the Heat Recovery Steam Generator in a combined cycle power plant

    , Article ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis, ESDA2010, 12 July 2010 through 14 July 2010, Istanbul ; Volume 1 , 2010 , Pages 201-209 ; 9780791849156 (ISBN) Karrabi, H ; Rasoulipour, S ; Sharif University of Technology
    2010
    Abstract
    The supplementary firing is one of the techniques which are used to increase the output power of the combined cycle power plants (CCPP). The low construction cost per generated power encourages designers to consider it in the new CCPP. In this paper the thermal and exergy analyses of HRSG for various operating conditions in variation of loads and variation of ambient temperature carried out. They are based on the performance test data at different operating conditions. The objective of these analyses is to present the effects of supplementary firing on gross power output, combined cycle efficiency and the exergy loss in Heat Recovery Steam Generator (HRSG) devices at different ambient...