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Mohammad Ali Mahdian, Amir Saemi, Vali Kalantar, Volume 17, Issue 3 (10-2014)
Abstract
Abstract: In this study we try to work on simulation of photovoltaic power plant with a focus on solar energy. For establishing a photovoltaic power plant, first there is a need for reliable software which can be used for estimating financial costs and annual production. Among existing softwares PVsyst and Sunny Design are two reliable softwares which their reliability is confirmed by comparing a case study of Yazd University photovoltaic power plant with the experimental data recorded at the power plant site. Input data for these softwares are gathered from plant locations geographical information and technical features of the equipments installed in the plant. After simulation step, output of both softwares are a collection of tables and graphs which demonstrate the hourly, monthly, and yearly energy produced of panels per square meter, system efficiency, energy production dispersion, system losses, and etc. In this study two methods for increasing power produced by the plant are suggested. One is putting the system on tracking mode in which a considerable increase in energy production can be seen from softwares results. The other method is cleaning the surface of the cells, results of which are shown by designing an experiment on panels and comparing the results with experimental data. In the end, the data achieved from these two softwares are compared with the experimental data recorded from the plant itself.
Hadi Sefidgar, Seyed Asghar Gholamian, Abdol Reza Sheikholeslami, Volume 17, Issue 3 (10-2014)
Abstract
The wind power system needs a controller to achieve the MPPT (Maximum Power Point Tracking), Due to the nonlinear characteristics of wind turbine. Mppt controller changes the rotor speed according to the variation of wind speed so that the tip speed ratio is optimal. There are many different techniques to extract maximum energy from wind system, as the most of these methods are based on the wind turbine maximum power curve and the wind speed profile. In this study, the new MPPT strategy is proposed for wind system with permanent magnet synchronous generator (PMSG), which predicts the maximum power point make use of fuzzy logic. The proposed method is completely independent of the properties of turbine and generator. So this method is not any mechanical sensor which will result in reduced costs and increased reliability of the system. The proposed MPPT controller, the main contribution of our work is in the model of DC-DC converter (boost converter), which allows the MPPT controller output (duty cycle) adjusts the voltage input of the converter to track the maximum power point of the wind generator.
Mohammad Reza Ashraf Khorasani, Hadi Goorabi, Isar Dashti, Minou Gholami Jourshari, Volume 18, Issue 2 (7-2015)
Abstract
Among the mid term actions of National Strategy of Iran Fuel Cell Technology Development, is designing and manufacturing polymer fuel cell system with the power of 10KW. However, this measure was performed before the commencement of this period. This article presents, in separate chapters, the steps of designing, manufacturing and testing the components, stack and the system of a 10 KW PEMFC. Finally, the advantages of this sample will be investigated in comparison with the first system made in Iran with the capacity of 5KW.
Mr Hamed Johnny Sarnavi, Dr Ali Mohammad Nikbakht, Mr Feyzolah Shahbazi, Mr Ali Hasanpor, Volume 18, Issue 2 (7-2015)
Abstract
The main issue of the study of solar energy potential which could be used for agro-food industrial consumption is the thermal efficiency modeling of these systems. A novel calculation algorithm based on steady state thermal analysis is presented for thermal performance study of a typical Flat Plate Solar Air Heater (FPSAH) in Urmia climate all the year around in 2009. Hence, the Urmia climate condition in 2009 was selected as work condition of FPSAH in modeling. The real and hourly data of ambient temperature and solar radiation which was recorded in Urmia airport meteorological station were used. The optimum tilt angles of FPSAH were applied in model. A calculating algorithm was developed for modeling and ran in MATLAB. The useful thermal gain, the thermal efficiency and the outlet temperature of FPSAH were considered as three parameters representing the thermal performance of a FPSAH. The result was presented as monthly averaged values at different radiation hour during the day, in the form of diagram and color counters. Some estimations of the extractable heat in different months of year, was achieved. This research results will be the first step of an optimized design and construction of a FPSAH supporting the real annual heat demand in Urmia climate.
Somayeh Ahmadi, Amir Hossein Fakehi, Volume 18, Issue 3 (10-2015)
Abstract
Inappropriate effects of fossil fuels and conventional power generation systems on the environment as well as the growing interests in renewable energy systems have necessitated a sustainable energy system for the next decade. Hydrogen is the one of known new energy fuel for sustainability that could generate by PEM electrolyzer. The present study was aimed at optimization of functional parameters of PEM electrolyzer by energy and exergy analysis. For this, we have developed a electrochemical- mechanical model by MATLAB and analyze the energy and exergy efficiency. The results revealed that increased of pressure and temperature cause to close the exergy efficiency to energy efficiency and improve the system performance. The optimal pressure and temperature respectively are 3 atm and 273 K. Also, the voltage of system are raised by increasing the current density.
Dr. Pouria Biparva, Mr. Mostafa Davoudinejad, Volume 18, Issue 3 (10-2015)
Abstract
In order to achieve sustainable development, along with implementation of energy management systems in wastewater treatment plants and reduce energy consumption, must try to offset all or part of the energy consumption of sewage treatment facility from potential of wastewater for energy production. Currently, biogas production in anaerobic reactors, microalgae cultivate and microbial fuel cell are known methods of producing energy simultaneous with wastewater treatment. Several parameters involve in the process of producing energy from wastewaters. Therefore, selection of optimal processes, is complex and difficult. First step is recognition of criteria and evaluate their effectiveness. In this research, prioritization and selection of the best option for energy producing method based on technical, economical, management and environmental criteria were done based on AHP method and experts judgment with special emphasis on the countrys infrastructure. Finally, the priorities determined as anaerobic treatment with 0.540, microalgae with 0.330 and microbial fuel cell with 0.130 weight.
, Volume 19, Issue 3 (10-2016)
Abstract
, , Volume 19, Issue 4 (1-2017)
Abstract
In this paper, a single switch transformerless high step up dc-dc converter with low voltage stress on the power switch for solar energy application is proposed. In the proposed converter only one power switch is used which makes the control scheme simple as well as reducing the switching power loss. The voltage gain of the proposed converter is higher than the conventional boost converter and buck boost converter. The proposed converter has low voltage stress on the power switch which makes reducing the switching power loss. The proposed converter can be operated in the continuous conduction mode (CCM) and the discontinuous conduction mode (DCM). In this paper, different operation modes of the proposed converter, calculation of the voltage gain, the currents that flow through the components, efficiency and capacitors voltage ripple are presented. To verify the operation of the proposed converter, simulation results via PSCAD software and experimental results are provided.
Seyed Mahdi Mahnama, Hamed Jannatamani, Volume 20, Issue 1 (4-2017)
Abstract
In this paper, the effect of operating conditions on the cathode of a fuel cell is made of plastic on its performance. For this purpose, two-dimensional and two-phase simulation of a fuel cell unit including gas ducts, gas diffusion layers and the cathode and the anode catalyst and the membrane area was conducted. The governing equations of the fuel cell using multi-phase model caraway and with regard to the single zone model was solved using coding and concentration VaknshGr components resulting in cell polarization curves were obtained. The effect of voltage, pressure, temperature, speed and relative humidity of the cathode on the concentration of oxygen and water as well as cell function studied and evaluated. The results show that by increasing the operating temperature of the cell, fuel cell performance improves. With increasing speed, pressure and relative humidity of the gas stream entering the channel, fuel cell efficiency increases. In order to validate the results obtained, the yield curve of single-phase and two-phase simulation compared with experimental results and good agreement was observed between them.
Mostafa Esmaeili Shayan, Gholamhassan Najafi, Ahmad Banakar, Barat Ghobadian, Volume 20, Issue 3 (12-2017)
Abstract
This paper presents a new method for the design and operation of photovoltaic power plants connected to the network anywhere in the country. Using an appropriate module and inverter can power while increasing efficiency and ideal use of solar energy potential, prevent power dissipation and system cost in different parts of the Draft .also prevent the loss of power in the shadow of modules on each other or the other computing takes place. The main characteristics of the panel and inverter design that is fit and homogeneity. HelioScope Software due to weather conditions and the geometry of the selection panel, the best way to offer the appropriate inverter type of wiring. SketchUp Software suitable guideline for evaluating the shadows during the year. Acoustic station Mehrabad NASA weather data and virtual stations can be used with high accuracy. Plant Mehrabad weather station data can yield% annual 7/78 and 3/735 MW due to the virtual station NASA 8/79% yield equivalent to 7/724 MW power generation have. The highest temperature and the lowest power dissipation in the wiring and inverter are mismatched.
Hamed Mousazadeh, Mansour Hosseini Firouz, Volume 20, Issue 3 (12-2017)
Abstract
In this study, we will investigate the possibility of using renewable energy resources in area where electrical energy is not supported. We will consider it as a micro-grid and we will try to supply its electrical energy by decreasing cost and having reliability in system. Generally, the main reason of designing and developing of distribution grid is responsible to growth of electrical consumption with maximum economic efficiency which the restriction of system is not made violation. Existing more elements in the distribution and sub-transmission networks have faced the designing and developing with problem where there are many decision variables. Advert of the distributed generation in distribution systems furthermore the changing operation of these systems provide this possibility to companies that can design systems with low cost. In this study, we aim to minimize the cost of the hybrid system of hydroelectric, wind, solar and battery and we will calculate LPSP index by GSO algorithm. It is designed and implemented for long-term network over 20-year.
Saeed Shavvalpour, Mona Asadi, Hamid Ghaderi, Volume 21, Issue 1 (6-2018)
Abstract
Biofuels have attracted much attention as a sutuible substitute for fossil fuels in last decade. Designing an efficient supply chain is an essential requirement for commercialization of biofuel production. This paper presents a mixed integer linear programming (MILP) model to design biofuel supply chains in which the biofuel demand is under ARMA time series models. It is studied how ARMA time series structure of biofuel demand affect the supply chain design. A numerical example is used to demonstrates application of the proposed model to design the most optimal biofuel supply chain. In addition, to provide insights for efficiently designing a biofuel supply chain, the ARMA models of biofuel demand is used to forecast the biofuel supply chain design for a 8-year.
Seyed Mojtaba Sadrameli, Nassim Dehqani, Volume 24, Issue 1 (6-2021)
Abstract
Abstract:
PCMs are materials with thermal storage capability which are used with two purposed in buildings: Increase the thermal interia of the building to greater use of the natural heat of the sun to heat and also reduce the need for heating and cooling by cooling-heating equipment. In this study the use of a pcm layer in the ceiling and walls of a building is simulated using the c++ software in a hot and humid climate (Boushehr) and cold and dry climate (Hamedan) to energy consumption and maintain indoor temperature close to comfortable temperature. The effects of PCM layer on reduce input/loss heat in summer and winter and the internal tempreture of the ceiling and walls were evaluted in all months of the year. Also, to explore the best orientation for the wall includes PCM, different orientation of the wall is simulated. The results showed that the phase change temperature of PCM should be in the range work of desired climate. Hence, PCM that used for a climate will not be suitable for another the use of a 3cm layer of PCM with the phase change temperature of 280C can reduce the input/loss heat through the roof of the building to 61% in summer and 12% in winter in Boushehr city. Also, by increasing the thickness of the PCM, it’s performance improvements in this area. The results of the simulation showed that the PCM in the wall facing south show best performance.
Dr Pedram Ghiasi, Dr Gholamhassan Najafi, Dr Barat Ghobadian, Dr Ali Jafari, Mr. Shafie Rahmati, Volume 25, Issue 3 (12-2022)
Abstract
The high power coefficient of the Darrius vertical axis wind turbine lift regime has prompted researchers to concentrate their efforts on this regime, despite the fact that these turbines suffer from major problems in the drag-lift regime. In the present study, in addition to exploring the performance of the Darrius type wind turbine at blade tip speeds above 1, the effect of design factors on its performance at TSRs below 1 is also investigated. The results were extracted from numerical analysis recruiting Fluent software and the k-w SST turbulence model. The effect of blade type, thickness, and chord length on turbine performance has been investigated. The blade angle at TSR less than one was calculated using a new equation, and the results were evaluated. The numerical simulation results showed that increasing the chord length for symmetric and asymmetric airfoils from 0.1 to 0.2 m enhances the turbine performance in drag-lift regime, whereas decreasing chord length improves turbine performance at higher TSRs. The blade with a curvature of 4% and a chord length of 0.1 m has the best performance at TSR 2.25. Increasing the thickness exerts a negative influence on the turbine's performance in both regimes, and at lower TSRs, NACA0018 airfoil with a chord length of 0.2 m was of the optimum performance in the drag-lift regime.
Hossien Dehghan, Javad Shokrolahi, Alireza Khoshsoadat, , Volume 26, Issue 2 (9-2023)
Abstract
In many studies related to electric vehicle charging, the charging station rate is either assumed to be a constant or a continuous value. While the mechanism of charging stations is not like this. The most common methods of charging lithium-ion batteries are the constant voltage-constant current, multi-stage, pulse or adaptive method. As far as the researchers of this article are concerned, little research has been done on the coordinated charging of electric vehicles, considering the technical details of the battery charging method and the nonlinear behavior of the vehicle battery at charge levels and charge rates. Although this idealistic view simplifies synchronized charge optimization, in practice it leads to increased internal battery losses, reduced battery life, damage to the charger, and a large discrepancy between simulation results and practical implementation. With the increasing penetration of electric vehicles, the need for practical charging methods has increased. In this paper, first, the adaptive current charging method of a lithium-ion battery is modeled, in which the charge current is changed inversely to the battery internal resistance in each state of charge interval to obtain the lowest battery losses. This model is then used for coordinated charging of electric vehicles, taking into account the interests of customers (reducing total charging costs) and the distribution network operation company (peak-shaving) in a real 37-bus network. The results show the efficiency of the proposed model in internal losses minimization of vehicle batteries, the total charging cost reduction and peak shaving of the network.
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