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Energy Equipment and Systems - Volume:6 Issue: 4, Autumn 2018

Energy Equipment and Systems
Volume:6 Issue: 4, Autumn 2018

  • تاریخ انتشار: 1397/09/13
  • تعداد عناوین: 7
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  • Mohsen Sharifi, Majid Amidpour, Saeed Mollaei * Pages 337-349
    Increasing electric vehicles usage, as a promising solution for environmental issues, might have unexpected implications, since it entails some changes in different sectors and scales in energy system. In this respect, this research aims at investigating the long-term impacts of electric vehicles deployment on Iran's energy system. Accordingly, Iran's energy system was analyzed by LEAP model in demand, supply, and transmission sides for all fuels and two different scenarios. Existing policies with limited optimistic assumptions was investigated as "reference" scenario. Alternatively, the other scenario, "electric cars" scenario, is gradually for substitution of electric vehicles for 15% gasoline cars until 2030 and renewable energy sources have more contribution in electricity production. Finally, carbon dioxide emission was predicted and compared in both scenarios for 25 years later. Results indicate that with "electric cars" scenario at 2030, Iran would have by 9.2 % and 1.9% less Carbon Dioxide emissions in comparison to the "reference" scenario in the transportation sector and total system, respectively.
    Keywords: Carbon Emission, Sustainability, Battery Electric Vehicles, Energy System Modeling
  • Seyed Hossain Ebrahimi* , Ahmad J.Afshari Pages 351-366
    The technical equipment developed and used in both installation and operation processes in refineries, oil and gas pipelines, and gas booster stations has always been expensive. Hence, managers at different organizational levels are keen to find methods to control and reduce these costs. Generally speaking, the operators in a gas booster station choose the operating devices without considering the related costs. This research presents a mixed integer nonlinear programming model designed to minimize the operational costs of gas booster stations in a main pipeline distribution network. The goal is to optimize the choice of operating devices in these stations to minimize costs while still meeting customer demands. Turbo compressors are chosen as the operating devices and the operational costs are fuel, maintenance, start-up, and penalty costs. However, the significance indexes of these costs are valued differently by the three expert managers: the executive officer, operating head, and the overhaul repairing director. Consequently, the analytical hierarchy process (AHP) method is used to calculate the overall weights of costs, and a gas transmission company in the north of Iran is considered as a case study. The model can minimize the total cost, when compared to the selections of ten experienced operators; however, the absolute weights of choosing measures and the essence of the objective function under study mean that an operator choice exists that would represent the optimum selection of turbo compressors.
    Keywords: Cost Benefit Analysis, Optimization, Natural Gas Transmission Network, Turbo Compressor, Mixed Integer Nonlinear Programming, Analytical Hierarchy Process
  • Amir Ghasemkhani , Said Farahat *, Mohammad Mahdi Naserian Pages 367-379
    In this research, the thermodynamic investigation of the tri-generation system is performed by the first and second law of Thermodynamics. The trigeneration system under study consists of three subsystems including the solar subsystem, Kalina subsystem and lithium bromide-water absorption chiller subsystem. The proposed system generates power, cooling and hot water using solar energy. The system considered is designed and evaluated based on the climate condition in Zahedan, Iran. The calculation results show that the most exergy destruction rate takes place in the solar cycle. The assessment of system is used dynamic and static forms. In dynamic form, that maximum total cost rate, energy and exergy efficiency are equal to 15.1 dollars per hour,by 33% and 36.47%, respectively. The results base-case demonstrate that energy and exergy efficiencies and total cost rates are equal to 9.63 dollars per hour by 17.37% and 18.82% , respectively in static analysis. Furthermore, optimization criteria comparison such as energy efficiency, exergy efficiency and power are discussed in static form. The results of static evaluation revealed that the power is the best criteria for thermodynamics. Moreover, optimization results based on maximum power criterion show that produced power, energy efficiency, exergy efficiency and total cost rate increase by 28%, 12.32%, of 13.97% and 7.68%, respectively in comparison with the base case.
    Keywords: Energy Analysis, Exergy Analysis, Parabolic Trough Solar Collector, Trigeneration, Solar Energy
  • Ali Ghasemi, Mohammad Hossein Refan*, Parviz Amiri Pages 381-392
    The effect of wind generator on sub-synchronous resonance (SSR) is being interested by increasing penetration of wind turbine in power systems,. Purpose of this article is to analyze SSR in a wind farm based on doubly fed induction generator (DFIG) which is connected to compensating series grid. A dynamic model for analysis of induction generator effect and Torsional Interaction (TI) has been utilized and simulated. The IEEE first benchmark model, is modified to include a 100 MW DFIG-based wind farm, is employed as a case study. three phenomena including a) series compensation level, b) the rotor speed, and c) effect of internal parameters of RSC controller on SSR are evaluated and the simulation results are analyzed.
    Keywords: DFIG, SSR, Torsional Interaction (TI), RSC Controller, GSC Controller
  • Elham Kazemi, Alireza Shateri * Pages 393-412
    In this study, a periodic zigzag channel with rectangular cross-section has been used in order to obtain a high-efficiency system for cooling a polymer electrolyte fuel cell. An appropriate function of fuel cells and enhancement of their lifetime require uniform temperature conditions of around 80°C. On the other hand, due to volume and weight constraints, a low-density compact heat exchanger is required, where the coolant fluid is water and the flow regime is laminar with a Reynolds number of 200. In order to consider these problems and increase the heat transfer rate under these conditions, a three-dimensional periodic zigzag channel is employed and the results are compared with the results which have been obtained for the straight channel. The results indicate that the zigzag channel generates chaotic advection and provides a good mixture of the hot fluid adjacent to the wall and the cool fluid away from it. This leads to a uniform temperature distribution along the channel. In addition, the values of Nusselt number and friction coefficient show that average Nusselt number in the zigzag channel is 6.5 times larger than that in the straight channel while the pressure drop remains approximately constant.
    Keywords: PEM Fuel Cell, Heat Transfer, Chaotic Advection, Zigzag Channel
  • Amirmohammad Behzadi, Ehsan Gholamian, Ehsan Houshfar*, Mehdi Ashjaee, Ali Habibollahzade Pages 413-427
    A novel solar-based combined system which is consisting of a concentrated PV, a double effect LiBr-H2O absorption chiller, and a Proton Exchange Membrane (PEM) is proposed for hydrogen production. A portion of the received energy is recovered to run a double effect absorption chiller and the rest is turned into electricity, being consumed in the PEM electrolyzer for hydrogen production. The thermodynamic and thermoeconomic analyses are performed to understand the system performance. A parametric study which is implementing Engineering Equation Solver (EES) is carried out to assess the influence of main decision parameters on the overall exergy efficiency and total product unit cost. The 2nd law analysis shows that PVT with exergy destruction rate of 76.9% of total destruction rate is the major source of irreversibility. Furthermore, in the cooling system, Cooling Set (CS) has the highest exergy destruction rate due to the dissipative components. Exergoeconomic results demonstrate that in cooling set with the lowest value of exergoeconomic factor, the cost of exergy destruction and loss has the major effect on the overall cost rate. Furthermore, results of the parametric study indicate that by decreasing PV cell’s temperature from 100 °C to 160 °C, the total product unit cost is decreased by about 1.94 $/GJ.
    Keywords: PVT, Cogeneration, Exergoeconomic, Double Effect LiBr-H2O, PEM
  • Bagher Shahbazi *, Faramarz Talati, S.Mohammad Seyyed Mahmoudi, Mortaza Yari Pages 429-448
    An integrated solar combined cycle (ISCC) is analyzed at "off-design" operating conditions. Using the principles of thermodynamics heat and mass transfer a computer code is developed in FORTRAN programming language to simulate the system’s hourly performance under steady state conditions. Three scenarios are considered for the study. In the first one, only the combined cycle (CC) is studied. In the second scenario, two solar heat exchangers are added to the system (ISCC) to produce some extra steam fed to the steam turbine for more power production. In the third one, as that of the ISCC scenario, a supplementary firing is used instead of solar heat exchangers to produce the same power. The main performance parameters are calculated for the hourly variation of solar direct normal irradiation intensity (DNI) and ambient air temperature for analyzing environmental benefits of using solar energy instead of supplementary firing. Results show that the contribution of solar energy in the annual produced power by the ISCC scenario is 75.14 GWh, which is 2.1% of the whole. In addition, it is found that using solar energy leads to an annual reduction of 36.13 Kton in the produced CO2 and an annual fuel saving of 3.76 ton.
    Keywords: Integrated Solar Combined Cycle, Solar Energy, Off-Design Model, Supplementary Firing, Environmental Benefits