Advanced Energy Technologies
Ashkan Nahvi Bayani; Mohammad Hadi Moghim; Saeed Bahadorikhalili; Abdolmajid Ghasemi
Abstract
Despite the extensive use of polyolefins, especially in the form of lithium-ion battery (LIB) separators, their flammability limits their large-scale battery applications. Therefore, the fabrication of flame-retardant LIB separators has attracted much attention in recent years. In this work, composite ...
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Despite the extensive use of polyolefins, especially in the form of lithium-ion battery (LIB) separators, their flammability limits their large-scale battery applications. Therefore, the fabrication of flame-retardant LIB separators has attracted much attention in recent years. In this work, composite separators were fabricated by applying a ceramic-based composite coating composed of a metal hydroxide as a filler and flame-retardant agent (Aluminium hydroxide, Al(OH)3) and a binder (Poly(vinylidene Fluoride-co-hexafluoropropylene), P(VDF-HFP)) to the polypropylene (PP) commercial separator. Thermal shrinkage, thickness, air permeability, porosity, wettability, ionic conductivity, flame retardancy, and electrochemical performance of the fabricated ceramic-coated composite separator were investigated. The results showed that the addition of Al(OH)3 particles improved thermal shrinkage ( 8 %) and flame retardancy of the commercial separator, which can prevent dimensional changes at high temperatures and significantly increase LIBs safety. Applied 11 µm ceramic-based coating layer on PP commercial separator had 76 % porosity that increased the value of air permeability from 278.15 (s/100 cc air) to 312.8 (s/100 cc air), causing much facile air permeation through the pores of commercial separator than the composite one. Furthermore, suitable electrolyte uptake and the contact angle of ceramic coated separator (135 % and 91.19°, respectively) facilitated ion transport through the pores, which effectively improved the ionic conductivity of Al(OH)3-coated PP separator (about 1.4 times higher than bare separator). Moreover, the cell comprising Al(OH)3-coated PP separator had better cyclic performance than that of bare PP separator. All these characteristics make the fabricated flame-retardant Al(OH)3 composite separator an appropriate candidate to ensure the safety of the large-scale LIB.
Advanced Energy Technologies
Shima Sharifi; Rahbar Rahimi; Davod Mohebbi-Kalhori; Can Ozgur Colpan
Abstract
The power density of a direct methanol fuel cell (DMFC) stack as a function of temperature, methanol concentration, oxygen flow rate, and methanol flow rate was studied using a response surface methodology (RSM) to maximize the power density. The operating variables investigated experimentally include ...
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The power density of a direct methanol fuel cell (DMFC) stack as a function of temperature, methanol concentration, oxygen flow rate, and methanol flow rate was studied using a response surface methodology (RSM) to maximize the power density. The operating variables investigated experimentally include temperature (50-75 °C), methanol concentration (0.5-2 M), methanol flow rate (15-30 ml min-1), and oxygen flow rate (900-1800 ml min-1). A new design of the central composite design (CCD) for a wide range of operating variables that optimize the power density was obtained using a quadratic model. The optimum conditions that yield the highest maximum power density of 86.45 mW cm-2 were provided using 3-cell stack at a fuel cell temperature of 75 °C with a methanol flow rate of 30 ml min-1, a methanol concentration of 0.5 M, and an oxygen flow rate of 1800 ml min-1. Results showed that the power density of DMFC increased with an increase in the temperature and methanol flow rate. The experimental data were in good agreement with the model predictions, demonstrating that the regression model was useful in optimizing maximum power density from the independent operating variables of the fuel cell stack.
Advanced Energy Technologies
Mohammad Sajjad Rostami; Morteza Khashehchi; Payam Zarafshan; Mohammad Hossein Kianmehr; Ehsan Pipelzadeh
Abstract
Capacitive deionization (CDI) is an emerging energy efficient, low-pressure and low-cost intensive desalination process that has recently attracted experts’ attention. The process is to explain that ions (cations and anions) can be separated by a pure electrostatic force imposed by a small bias ...
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Capacitive deionization (CDI) is an emerging energy efficient, low-pressure and low-cost intensive desalination process that has recently attracted experts’ attention. The process is to explain that ions (cations and anions) can be separated by a pure electrostatic force imposed by a small bias potential. Even at a rather low voltage of 1.2 V, desalinated water can be produced. The process can be well operational by a professional cell design. Although various processes have been manufactured before, in this study, membrane was removed and a new unit was designed and manufactured (Using CFD Simulation). In this case, the combination of activated carbon powder (with an effective surface area of 2600 m2 per gram), carbon black, and polyvinyl alcohol with a ratio of 35/35/30 coated on carbon paper as electrode materials was considered for tests. The weight was 1.41 grams for each material, and the thickness was 0.44 mm. CDI system was tested, and the results of charge-discharge cycles, cyclic voltammetry, and impedance spectroscopy were evaluated. It can be implied that there is no need for a strong pump and, also, pressure drop can be reduced due to such a noticeable space between two electrodes. Preliminary experimental results showed high specific capacitance (2.1 Farad) and ultra-high salt adsorption capacity, compared with similar cases.
Advanced Energy Technologies
Negin Maftouni; Minoo Askari
Abstract
Both energy and environmental criticisms push a society toward energy-efficient buildings with green technologies. Green roofs are of significant importance due to their remarkable role in decreasing the thermal loads ofbuildings, especially in summer, and also in sound insulation. Here in, the thermal ...
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Both energy and environmental criticisms push a society toward energy-efficient buildings with green technologies. Green roofs are of significant importance due to their remarkable role in decreasing the thermal loads ofbuildings, especially in summer, and also in sound insulation. Here in, the thermal loads of a residential building were calculated, and then, an optimized green roof was designed for it in three different cities of Tehran, Rasht, and Tabriz. The energy saving was analyzed in each case, and proper plants and roof thickness were selected to achieve both comfortable air conditioning and energy optimization. It is also important to use water resources in an optimized manner. Considering the annual mean rain magnitude, here, a suitable system is designed to harvest rainwater for watering the plants. Results indicate that a sedum grass-based green roof with the thickness of 10 cm leads to a 21.3 % reduction in the annual total thermal loads in Tehran; one with thickness of 8 cm in Tabriz will result in a 11.7 % thermal load reduction per year; a green roof with 9 cm thickness in Rasht, Iran shows 13.2 % energy saving per year. Therefore, Tehran is the best option here to integrate the green roof into the structure of the building. The patterns of the obtained data indicate that the reduction of cooling loads is more noticeable when implementing a green roof in comparison with heating loads. Moreover, it has been revealed that harvested rainwater is sufficient to support about 72 % of required water in Tehran, 81 % of it in Tabriz, and 93 % in Rasht.
Advanced Energy Technologies
Vajihe Yousefi; Davod Mohebbi-Kalhori; Abdolreza Samimi
Abstract
The effect of the thickness of ceramic membrane on the productivity of microbial fuel cells (MFCs) was investigated with respect to the electricity generation and domestic wastewater treatment efficiencies. The thickest ceramic membrane (9 mm) gained the highest coulombic efficiency (27.58±4.2 ...
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The effect of the thickness of ceramic membrane on the productivity of microbial fuel cells (MFCs) was investigated with respect to the electricity generation and domestic wastewater treatment efficiencies. The thickest ceramic membrane (9 mm) gained the highest coulombic efficiency (27.58±4.2 %), voltage (681.15±33.1 mV), and current and power densities (447.11±21.37 mA/m2, 63.82±10.42 mW/m2) compared to the 6- and 3-mm thick separators. The results of electrochemical impedance spectroscopy (EIS) analysis were investigated to identify the internal resistance constituents by proposing the appropriate equivalent electrical circuit. The Gerischer element was modeled as the coupled reaction, and diffusion in the porous carbon electrodes and the constant phase element was assimilated into the electrical double-layer capacitance. The thickest ceramic (9 mm) was found to have the largest ohmic resistance; however, owing to its superior barrier capability, it provided more anoxic conditions for better accommodation of exoelectrogenic bacteria in the anode chamber. Therefore, lower charge transfer, fewer diffusional impedances, and higher rates of anodic reactions were achieved. Excessive oxygen and substrate crossover through the thinner ceramics (of 6 and 3 mm) resulted in the suppressed development of anaerobic anodic biofilm and the accomplishment of aerobic substrate respiration without electricity generation.
Advanced Energy Technologies
Imad-Eddine Fahs; Majid Ghasemi
Abstract
Converting chemical energy into electricity is done by an electro-chemical device known as a fuel cell. Thermal stress is caused at high operating temperature between 700 oC to 1000 oC of SOFC. Thermal stress causes gas escape, structure variability, crack initiation, crack propagation, and cease operation ...
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Converting chemical energy into electricity is done by an electro-chemical device known as a fuel cell. Thermal stress is caused at high operating temperature between 700 oC to 1000 oC of SOFC. Thermal stress causes gas escape, structure variability, crack initiation, crack propagation, and cease operation of the SOFC before its lifetime. The aim of this study is to present a method that predicts the initiation of cracks in an anisotropic porous planar SOFC. The temperature and stress distribution are calculated. The code uses the generated data, stress intensity factor, and the J-integral of the materials to predict the initiation of the crack inside the porous anode and cathode. The results show that the highest thermal stress occurs at the upper corners of cathode and at the lower corners of the anode. In addition, the thickness of cathode electrode on the left side is increased by 1.5 %. Finally, the crack initiation occurs on the left side between the upper and lower corners of the cathode.
Advanced Energy Technologies
Maryam Rahmani; Faramarz Faghihi; Hassan Moradi CheshmehBeigi; Seyed Mehdi Hosseini
Abstract
In this paper, the effect of a static synchronous compensator (STATCOM) influence on the frequency of islanded microgrids based on frequency control using fuzzy cooperative control is investigated. To achieve fast frequency control, instantaneous power balance between generation and consumption is inevitable, ...
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In this paper, the effect of a static synchronous compensator (STATCOM) influence on the frequency of islanded microgrids based on frequency control using fuzzy cooperative control is investigated. To achieve fast frequency control, instantaneous power balance between generation and consumption is inevitable, and it can be supplied through energy storage systems such as battery with a proper frequency control method. Besides, the frequency control of islanded microgrids could be studied under different circumstances, where one aspect analyzed is added to a flexible AC transmission system (FACTS) device, such as STATCOM, in the microgrids. Although STATCOM is charged with improving the voltage profile, it can affect frequency stability by adjusting the voltage very quickly. Due to the importance of refining frequency stability, two controller methods are compared: a classic PI controller and a fuzzy PID controller. Accordingly, the performance of STATCOM is evaluated via two scenarios. Based on simulation results, by applying the fuzzy PID controller to the microgrid, STATCOM can reach the nominal frequency. Moreover, with greater validation and investigation of this topic, this device could be an agreeable alternative to the battery energy storage system (BESS).
Advanced Energy Technologies
Mohammad Zarei-Jelyani; Shaghayegh Baktashian; Mohsen Babaiee; Rahim Eqra
Abstract
In recent years, many studies have focused on the active materials of anodes to improve the performance of LIBs, while limited attention has been given to polymer binders, which act as inactive ingredients. However, polymer binders have amazing influence on the electrochemical performance of anodes. ...
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In recent years, many studies have focused on the active materials of anodes to improve the performance of LIBs, while limited attention has been given to polymer binders, which act as inactive ingredients. However, polymer binders have amazing influence on the electrochemical performance of anodes. Herein, to investigate the binding performance between MCMB artificial graphite and the copper current collector, three binders such as PVDF, MSBR, and CMC+SBR were used to prepare the anode electrodes. The mechanical and electrochemical tests were conducted for different MCMB electrodes. The results show that the water-based binders (CMC+SBR and MSBR) made better adhesion properties for the coating on the current collector in comparison with the organic solvent-based binder (PVDF). MCMB anode fabricated with CMC+SBR binder shows the highest discharge capacity and the best rate performance at various C-rates of 0.2C, 0.5C, and 1C that result in the brilliant electrochemical performance. Therefore, artificial graphite anode materials using cheap aqueous CMC+SBR binder instead of toxic solvent like NMP and expensive PVDF improve electrochemical property and reduce the cost of LIBs.
Advanced Energy Technologies
Mohammad Jafari; Hossein Ghadamian; Leila Seidabadi
Abstract
The study of the battery charge process as the only power storage agent in off-grid systems is of significant importance. The battery charge process has different modes, and the battery in these modes is dependent on the amount of charge. In order to charge the battery in off-grid systems, two charge ...
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The study of the battery charge process as the only power storage agent in off-grid systems is of significant importance. The battery charge process has different modes, and the battery in these modes is dependent on the amount of charge. In order to charge the battery in off-grid systems, two charge controllers including Pulse Width Modulation (PWM) and Maximum Power Point Tracker (MPPT) are commonly used. The charge rate (C-Rate) is different in these two models. Therefore, it is necessary to study the state of charge (SoC) in the PWM and MPPT models considerably. In this study, by using these two charge controller models, C-Rate is examined on portable and power plant scales. This research indicates that the PWM charge controller has better performance on the power plant scale than on the portable scale. The charging quality of the MPPT model is about 31 % and 7 % on portable and power plant scales, respectively, proved to be higher than that of the PWM charge controller. The PV panel performance has increased by 2 %-5 % through the application of the MPPT charge controller, compared with the PWM model. As the overall achievement of the experiment, according to the limitations of the MPPT charge controller, the PWM charge controller can be proposed on power plant scales, whereas the application of the MPPT model is appropriate for specific purposes.
Renewable Energy Resources and Technologies
Negin Maftouni; Kiana Motaghedi
Abstract
Traditional fossil fuels, which are also depleting cause environmental problems. A significant portion of global energy consumption is due to building air conditioning systems. Nowadays, considerable attention is drawn to renewable and sustainable energy sources to support the energy requirements of ...
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Traditional fossil fuels, which are also depleting cause environmental problems. A significant portion of global energy consumption is due to building air conditioning systems. Nowadays, considerable attention is drawn to renewable and sustainable energy sources to support the energy requirements of buildings. In this study, a solar absorption chiller was designed for a three-floor residential building in hot and arid climate. At first, thermal loads in the building were calculated using Carrier software. The material and color of the exterior walls, as well as window types, were changed to reduce the heat transfer coefficient and get an optimum design. Results indicate that by using the optimum design, maximum heating load reduction and maximum cooling load reduction can be achieved with approximate rates of 37 % and 12 %, respectively. Considering safety factor and based on the maximum cooling load, a single-effect LiBr-water solar absorption chiller was designed for the optimum building. Two different scenarios were suggested using two types of flat plate and evacuated tube collector. Results show that in the case of evacuated tube collector the net collector area of 254.18 m2 is sufficient to supply the cooling power. Implementing flat plate collectors would result in occupying an area of 398.5 m2. Regarding the limitation of total area of roof and efficiency issues, the evacuated tube collector is the best option.
Advanced Energy Technologies
Hassan Ali Ozgoli
Abstract
Fuel cell-based hybrid cycles that include conventional power generators have been created to modify energy performance and output power. In the present paper, integrated biomass gasification (IBG)-molten carbonate fuel cell (MCFC)-gas turbine (GT) and steam turbine (ST) combined power cycle is introduced ...
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Fuel cell-based hybrid cycles that include conventional power generators have been created to modify energy performance and output power. In the present paper, integrated biomass gasification (IBG)-molten carbonate fuel cell (MCFC)-gas turbine (GT) and steam turbine (ST) combined power cycle is introduced as an innovative technique in terms of sustainable energy. In addition, biomass gasification has been explained and shown able to supply the required fuel to the energy generators to compensate for the consumption consequences of fossil fuels. In this system, a molten carbonate fuel cell generates electricity from syngas produced by biomass gasification. In addition, a gas cleaning process prepares adequate treatment before consumption in the fuel cell. Furthermore, for the justification of this system as a combined heat and power (CHP) cycle, a considerable amount of produced heat in the proposed process generates power in GT and ST bottoming cycles. Due to the energy targeting, modeling and simulation of the presented system were fulfilled by the Cycle-Tempo software, and the results showed about 42 MW output power and total efficiency of around 83 %. Further to that, parametric studies represented the durability of the generated power against ambient temperature variations. Finally, changes in total power and efficiency due to the fluctuation of the moisture content of biomass, pressure ratio, and inlet temperature of GT have also been demonstrated.
Advanced Energy Technologies
Mohammad Zarei-Jelyani; Mohammad Sarshar; Mohsen Babaiee; Nima Tashakor
Abstract
Accurate lifetime prediction of lithium-ion batteries is a great challenge for the researchers and engineers involved in battery applications in electric vehicles and satellites. In this study, a semi-empirical model is introduced to predict the capacity loss of lithium-ion batteries as a function ...
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Accurate lifetime prediction of lithium-ion batteries is a great challenge for the researchers and engineers involved in battery applications in electric vehicles and satellites. In this study, a semi-empirical model is introduced to predict the capacity loss of lithium-ion batteries as a function of charge and discharge cycles, operational time, and temperature. The model parameters are obtained by minimizing the prediction errors of experimental capacity loss for each charge/discharge cycle at 25 oC, 35 oC, and 45 oC.The optimum values of the model parameters are obtained using genetic algorithm, one of the optimization tools in Matlab software. The model accurately predicts the capacity loss of lithium-ion battery for more charge and discharge cycles at 25 °C with an average error of 4 %. The mentioned cycles are used only to validate the prediction.
Advanced Energy Technologies
Tuhid Pashaee Golmarz; Sajad Rezazadeh; Narmin Bagherzadeh
Abstract
In this paper, a three-dimensional, single-phase proton-exchange membrane fuel cell (PEMFC) is studied numerically. Finite volume method was used for solving the governing equations and, consequently, the numerical results were validated by comparing them with experimental data, which showed good agreement. ...
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In this paper, a three-dimensional, single-phase proton-exchange membrane fuel cell (PEMFC) is studied numerically. Finite volume method was used for solving the governing equations and, consequently, the numerical results were validated by comparing them with experimental data, which showed good agreement. The main objective of this work is to investigate the effect of a novel gas channel shape– by applying sinusoidal gas channel- on the cell performance and mass transport phenomena. Some parameters such as oxygen consumption, water production, protonic conductivity, and temperature distribution for two cell voltages were studied, and the results were compared with respect to conventional and new models. The results indicated that the new novel model showed better performance than the conventional model, especially at low cell voltages, causing an increase in oxygen consumption and water production. Therefore, based on a number of investigated relations, a higher rate of current density was obtained, thus enhancing the fuel cell performance. This is because the incoming species path to the gas channels in the new model becomes longer. Therefore, the diffusion of the species toward the electrochemical reaction area increased.
Advanced Energy Technologies
Tamer Nabil; Mohamed Khairat Dawood; Tamer Mansour
Abstract
Since the renewable resources of energy have become extremely important, especially wind energy, scientists have begun to modify the design of the wind turbine components, mainly rotor blades. Aerodynamic design considered a major research field related to power production of a small horizontal wind ...
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Since the renewable resources of energy have become extremely important, especially wind energy, scientists have begun to modify the design of the wind turbine components, mainly rotor blades. Aerodynamic design considered a major research field related to power production of a small horizontal wind turbine, especially in low wind speed locations. This study displays an approach to the selection of airfoil and blade design utilized in small horizontal wind turbines with low cut-in speed and with no gear box. Modeling of the flow depends on Computational Fluid Dynamics (CFD) and theory of Blade Element Momentum (BEM) methodologies. QBlade used (BEM) for wind turbine simulation and integrated with XFOIL for airfoils design to ensure the requested characteristics for wind turbine performance. MATLAB is used to calculate the final design parameters to be modeled in SOLIDWORK. The flow dynamics are explored with the aid of ANSYS Fluent 16. The application of specially designed blades grants start up at lower wind speeds. The designed blade is fabricated from polyurethane foam. Experimental study confirmed that, at low average wind velocity (4m/s), the fabricated small-scale horizontal wind turbines are considered to be a positive way to supply electricity with an average power rate of 9watt and efficiency of 8%.
Advanced Energy Technologies
Marzieh Moein; Somayeh Pahlavan; Mehdi Jahangiri; Akbar Alidadi Shamsabadi
Abstract
The electricity economy and its excessive consumption have become one of the main concerns of the Iranian government for many years. This issue, along with recent droughts, shows the need to use renewable energy that is free and clean and does not require water. In addition, due to the high cost of cable-laying ...
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The electricity economy and its excessive consumption have become one of the main concerns of the Iranian government for many years. This issue, along with recent droughts, shows the need to use renewable energy that is free and clean and does not require water. In addition, due to the high cost of cable-laying and maintenance of power lines, it is not at all an option at all distances over the development of the national electricity grid. Therefore, it is important to find a distance for farther distances so that the use of renewable energy systems can be superior to the national electricity grid. According to related studies conducted so far, nothing has been done in this regard in Iran untill private-sector investors realize that, for what distances from the national grid, the network development is not cost-effective compared to using renewables. Therefore, in the present work, by using NASA's wind and solar data, 102 stations in Iran were investigated using the HOMER software. The studied system is a solar-wind one backed up by batteries and diesel generator for emergency conditions. The results showed that the average total net present cost of the solar-wind hybrid system in Iran was to provide a daily average electricity load of 5.9 kWh of a residential building with a peak load of 806 W equal to $ 12415, which could on average provide 95.3% of the building's needs by renewable energy. The average minimum distance from the national grid is 593 m for the cost-effective use of renewable energy.
Advanced Energy Technologies
Neda Azizi; Hassan Moradi CheshmehBeigi
Abstract
This paper focuses on improving the active and reactive power control of Wind Energy Conversion System (WECS) by employing the Battery Energy Storage System (BESS) and controlling the frequency and voltage regulation instantaneously. The proposed power control scheme is composed of two control loops ...
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This paper focuses on improving the active and reactive power control of Wind Energy Conversion System (WECS) by employing the Battery Energy Storage System (BESS) and controlling the frequency and voltage regulation instantaneously. The proposed power control scheme is composed of two control loops so that they are implemented and designed for active power control and controlling the reactive power, respectively, which both are equipped with PI type controllers. In addition, two control loops were utilized to control the frequency and voltage on the rotor side converter under balance and unbalance grid conditions. In this paper, the presented control strategy optimally tuned all the parameters of controllers at the same time by utilizing a mixed integer nonlinear optimization programming and solved by the ICA algorithm. Moreover, in order to demonstrate the effectiveness of the proposed strategy, non-linear time domain simulations were carried out in MATLAB software. The obtained simulation results verified that the proposed control scheme efficiently utilize BESS to control the active and reactive power control and confirm the effectiveness of the proposed strategy under the balanced and unbalanced grid conditions.