Advanced Energy Technologies
Maryam Keshavarz; Davod Mohebbi-Kalhori; Vajihe Yousefi
Abstract
Response surface methodology is employed to statistically identify the significance of three parameters of separator assembly arrangement, wastewater flow rate, and relative flow patterns of anode and cathode influencing the generation of power and coulombic efficiency of Microbial Fuel Cells (MFCs). ...
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Response surface methodology is employed to statistically identify the significance of three parameters of separator assembly arrangement, wastewater flow rate, and relative flow patterns of anode and cathode influencing the generation of power and coulombic efficiency of Microbial Fuel Cells (MFCs). Three different assemblies of Nylon-Cloth (NC), artificial rayon cloth as Absorbent Layer (AL), and J-Cloth (JC) were investigated as proton exchange mediums instead of common expensive polymeric membranes. Statistical analyses (ANOVA) revealed that although the addition of the AL after the JC layer had no significant impact on the enhancement of maximum power density, it could improve the coulombic efficiency of the MFCs by 15 %, owing to the crucial impact of oxygen permeability control between the MFC chambers. In the counter-current flow pattern, higher trans-membrane pressure and more oxygen concentration differences diminished the MFC performance and marked the importance of efficient separator layer arrangement, compared to co-current influents. The maximum power density of 285.89 mW/m2, the coulombic efficiency of 4.97 %, and the internal resistance of 323.9 Ω were achieved for the NC-JC-Al arrangement in the co-current mode along with the flow rate of 6.9 ml/min. The higher the flow rate of influent wastewater, the higher the performance of the MFCs.
Advanced Energy Technologies
Vahid Nazari; Mohammad Hossein Mousavi; Hassan Moradi CheshmehBeigi
Abstract
Over the past decades, power engineers have begun to connect power grids to other networks such as microgrids associated with renewable units using long transmission lines to provide higher reliability and greater efficiency in production and distribution besides saving resources. However, many dynamic ...
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Over the past decades, power engineers have begun to connect power grids to other networks such as microgrids associated with renewable units using long transmission lines to provide higher reliability and greater efficiency in production and distribution besides saving resources. However, many dynamic problems such as low frequency oscillations were observed as a result of these connections. Low frequency oscillation is a normal phenomenon in most power systems that causes perturbations and, thus, the grid stability and damping process are of paramount importance. In this paper, to attenuate these oscillations, a novel method for designing Power System Stabilizer (PSS) is presented via Linear Parameter-Varying (LPV) approach for a Single Machine Infinite Bus system (SMIB). Because the system under study is subject to frequent load and production changes, designing the stabilizer based on the nominal model may not yield the desired performance. To guarantee the flexibility of the stabilizer with respect to the aforementioned issues, the power system polytopic representation is used. In order to apply the new method, the nonlinear equations of the system at each operating point, located in a polytope, are parametrically linearized by scheduling variables. Scheduling variables can be measured online in any operating point. By using this model and following the H∞ synthesis, feedback theories, and Linear Matrix Inequalities (LMIs), LPV controllers at all operating points are obtained. Finally, the simulation results verify the effectiveness of the proposed controller over classic and robust controllers with regard to uncertainties and changes in system conditions.
Advanced Energy Technologies
Padmanabhan Sambandam; Parthasarathy Murugesan; Mohamed Iqbal Shajahan; Balaguru Sethuraman; Hussein Mohamed Abdelmoneam Hussein
Abstract
Environmental sustainability encompasses various problems including climate change, clean air, renewable energy, non-toxic environments, and capacity to live in a healthy community. Many researchers focus their attention on alternative energy sources, such as ethanol and hydroxy gas, to enhance environmental ...
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Environmental sustainability encompasses various problems including climate change, clean air, renewable energy, non-toxic environments, and capacity to live in a healthy community. Many researchers focus their attention on alternative energy sources, such as ethanol and hydroxy gas, to enhance environmental health and quality of life. The introduction of hydroxy gas as a clean source of energy is gaining significant traction. Also, ethanol has a greater octane number than gasoline. Therefore, the ethanol–gasoline blend has a higher octane number than conventional gasoline. A new combination of hydroxy gas, ethanol, and gasoline is environmentally benign while significantly improving the performance of gasoline engines. This paper tested hydroxy gas in a 197-cc gasoline engine power generator powered with ethanol–gasoline blend. The results demonstrated that thermal efficiency increased up to 23.6 % and fuel consumption decreased up to 36 % on a volume basis, which was a significant improvement over the base engine. Furthermore, the hazardous carbon monoxide reduction reached 11.45 % and the unburned hydrocarbon emissions reached 17.6 %.
Advanced Energy Technologies
Mohsen Babaiee; Mohammad Zarei-Jelyani; Shaghayegh Baktashian; Rahim Eqra
Abstract
A mechanical technique was applied to the copper current collector of lithium-ion battery anode to improve interface adhesion between Cu foil and anode film. The mechanical and electrochemical performances of graphite anodes coated on Bare Cu Foil (BCF) and Modified Cu Foil (MCF) were evaluated. The ...
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A mechanical technique was applied to the copper current collector of lithium-ion battery anode to improve interface adhesion between Cu foil and anode film. The mechanical and electrochemical performances of graphite anodes coated on Bare Cu Foil (BCF) and Modified Cu Foil (MCF) were evaluated. The BCF and MCF anodes exhibited adhesion strengths of 1.552 and 1.617 MPa, respectively. The electrochemical studies of BCF and MCF anodes showed that the initial discharge capacity of graphite anode coated on the MCF (323.6 mAh g-1) was about 8 % higher than the BCF anode (299.9 mAh g-1). The BCF anode capacity reached 227.9 mAh g-1 after 100 charge/discharge cycles at 0.5C rate, while this value was 247.7 mAh g-1 for MCF anode. The results of electrochemical impedance spectra demonstrated that the diffusion coefficient of lithium-ion for MCF anode was about 56 % higher than that for BCF anode. On the other hand, the surface modification of the copper current collector reduced the charge transfer resistance of anode from 28.5 Ω to 23.2 Ω.
Advanced Energy Technologies
Ghasem Alahyarizadeh; Maryam Amirhoseiny; Majid Khorsandi
Abstract
The performance characteristics of InGaN Double-Quantum-Well (DQW) Laser Diodes (LDs) with different barrier structures were studied numerically by Integrated System Engineering Technical Computer-Aided Design (ISE TCAD) software. Three different kinds of structures of barriers including quaternary AlInGaN ...
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The performance characteristics of InGaN Double-Quantum-Well (DQW) Laser Diodes (LDs) with different barrier structures were studied numerically by Integrated System Engineering Technical Computer-Aided Design (ISE TCAD) software. Three different kinds of structures of barriers including quaternary AlInGaN and AlInGaN/AlGaN superlattice barriers were used and compared with conventional GaN in InGaN-based laser diodes. Replacing the traditional GaN barriers with quaternary AlInGaN increased holes and electrons flowing in the active region and thus, the radiative recombination enhanced the output power. However, it did not reduce the threshold current due to hole and electron overflowing. To investigate the ways of greatly reducing the threshold current, the structure consisting of AlInGaN/AlGaN superlattice barriers was proposed. The simulation showed that electrical and optical characteristics such as output power, Differential Quantum Efficiency (DQE), and slop efficiency were significantly enhanced for LDs containing superlattice barriers compared to the basic structure. This is while the threshold current was considerably reduced. The enhancement was mainly attributed to the improvement of hole injection and also the blocking hole and electron overflowing caused by the reduction of polarization charges at the interface between the barriers, the well, and the Electron Blocking Layer (EBL).
Advanced Energy Technologies
Sedigheh Sadegh Hassani; Leila Samiee
Abstract
In the present work, natural biomass and chemical materials were applied as the heteroatom resources for modifying the Porous Graphene (PG) structure by pyrolysis method at 900 ºC. The physical and chemical characterizatons were performed by means of Scanning Electron Microscopy (SEM), Brunauer–Emmett–Teller ...
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In the present work, natural biomass and chemical materials were applied as the heteroatom resources for modifying the Porous Graphene (PG) structure by pyrolysis method at 900 ºC. The physical and chemical characterizatons were performed by means of Scanning Electron Microscopy (SEM), Brunauer–Emmett–Teller (BET), Raman Spectroscopy, N2 Adsorption-Desorption, and X-ray Photo-electron Spectroscopy (XPS). Furthemore, the behavior of the prepared materials was investigated by Cyclic Voltammetry (CV) and Rotating Disk Electrode (RDE). The obtained results indicated that doping of heteroatoms into the graphene framework was possible using a low-cost and environment-friendly biomass material as well as chemical sources. Moreover, one-step quarternary and tersiary co-doped graphene could be acheived using natural biomass. The prepared electrocatalysts using grape leaves and sulfur trioxide pyridine complex exhibit higher electrocatalytic performance as exampled which conducted the electrocatalyst in 4e- pathway and showed high stability in methanol solutions during the process, confirming their considerable potential to Oxygen Reduction Reaction (ORR) as an electro-catalyst. Moreover, the onset potential of Gl300G-900 and GSP 900 (0.93 V vs RHE) is almost equal to the Pt/C 20 wt % (0.99 V vs RHE). These optimal prepared cathodes (Gl300G-900 and GSP 900) in the Microbial Fuel Cell (MFC) test lead to considerable power densities of 31.5 mW m-2 and 30.9.mW m-2, which are close to 38.6 mW m-2 for the Pt/C 20 wt % cathode.
Advanced Energy Technologies
Iessa Sabbe Moosa; Hussein A Kazem; Laila Masoud Rashid Al-Iessi
Abstract
Studies on renewable energy are essential topics that help find new energy sources to replace fossil sources and promote environment friendliness. Hydrogen is the most practical alternative energy carrier source that meets the mentioned purposes. The mass of hydrogen element in the Earth's water was ...
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Studies on renewable energy are essential topics that help find new energy sources to replace fossil sources and promote environment friendliness. Hydrogen is the most practical alternative energy carrier source that meets the mentioned purposes. The mass of hydrogen element in the Earth's water was calculated and found to be about 2.1×1020 kg, which is greater than the mass of the world oil reserves by about 9×105 times. In addition, essential details of water molecular arrangement were investigated in order to better understand the electrolysis of water. Also, the energy of covalent and hydrogen bonds per molecule of water was theoretically calculated and found to be about 8.17×10-19 J/molecule and 3.87×10-20 J/molecule, respectively. In the electrolysis process, two stages should be undertaken: the first stage was to break hydrogen bonds between water molecules, in which all water eclectic dipoles would align in the direction of the Applied Electric Field across the electrolysis unit. The second stage was to break water covalent bonds to generate H2 and O2 gases. Moreover, the lowest cost to generate one kg of hydrogen (0.4 $/kg) by electrolysis method using solar energy was about 0.4 $, which has already been proven, while this value was about 2.8 $/kg upon considering the average price of electricity of Oman in comparison.
Advanced Energy Technologies
Samira Jafari; Mehran Ameri Mahabadi
Abstract
As a result of growing energy demand, shortage of fossil fuel resources, climate change, and environmental protection, the need for renewable energy sources has been growing rapidly. However, there is an urgent need to cope with intermittency and fluctuation of renewable energies. Various energy storage ...
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As a result of growing energy demand, shortage of fossil fuel resources, climate change, and environmental protection, the need for renewable energy sources has been growing rapidly. However, there is an urgent need to cope with intermittency and fluctuation of renewable energies. Various energy storage systems are considered as appropriate solutions to the above-mentioned problem. In the present manuscript, a novel compressed carbon dioxide energy storage system was proposed. Furthermore, an extra thermal energy storage with Therminol VP-1 as a working fluid, coupled with Parabolic Trough Collector (PTC), was added to the system. This integration is conducive to rising the inlet temperature of turbines and reducing the work load that should be done by the compressors. In the present study, a method based on software product including Engineering Equation Solver (EES) for determining thermodynamic characters per component and System Advisor Model (SAM) was employed to model the solar field for a desired location. Energy and exergy analyses were conducted to evaluate the whole cycle performance during charging and discharging periods. In this study, the city of Kerman located in the south-eastern part of Iran, with Direct Normal Incidence (DNI) of 950 , was selected for the present modeling. The results of a random day (June 22/2019) at time 15:00 represented the exergy efficiency of 66.98 % and the round trip efficiency of 93.14 %. High exergy efficiency and round trip efficiency of this system make this idea applicable to enhancing the total performance of the entire system.
Advanced Energy Technologies
Iraj Mirzaee; Aref Razmjoo; Nader Pourmahmoud
Abstract
This study conducts thermodynamic analysis on three trigeneration cycles including Organic Rankine Cycle (ORC), Liquefied Natural Gas (LNG) cold energy, and absorption refrigeration cycle in order to select appropriate working fluids. Different types of ORC cycles including simple ORC, regenerative, ...
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This study conducts thermodynamic analysis on three trigeneration cycles including Organic Rankine Cycle (ORC), Liquefied Natural Gas (LNG) cold energy, and absorption refrigeration cycle in order to select appropriate working fluids. Different types of ORC cycles including simple ORC, regenerative, and ORC with Internal Heat Exchange (IHE) were investigated. For those types, the operation of six working fluids with different thermodynamic behaviors (R141b, R124, R236fa, R245fa, R600, and R123) was evaluated. In power plants, a low-grade heat source was provided by condensing boiler hot water energy while the thermal sink was prepared by cold energy of LNG. The effect of boiler temperature variation on energy and exergy efficiencies was investigated. According to the derived results, regenerative ORC-based systems possessed maximum energy and exergy efficiencies, while simple ORC and ORC with internal heat exchanger exhibited approximately the same quantities. Also, among these analyzed working fluids, R141b had the maximum energetic and exergetic efficiencies, while R124 and R236fa had minimum performance.
Advanced Energy Technologies
Ehsan Hasan Zaim; Hadi Farzan
Abstract
Utilizing thermal storage units such as Phase Change Materials (PCMs) is a suitable approach to improving Solar Air Heaters (SAHs). The present study tries to assess the effects of PCM mass values on the heat dynamics and thermal performance of SAHs. To this aim, an analytical thermodynamic model was ...
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Utilizing thermal storage units such as Phase Change Materials (PCMs) is a suitable approach to improving Solar Air Heaters (SAHs). The present study tries to assess the effects of PCM mass values on the heat dynamics and thermal performance of SAHs. To this aim, an analytical thermodynamic model was developed and validated by available experimental data. This model provides a robust numerical framework to model the phase change phenomenon and analyze the heat dynamics and thermal performance of SAH using various PCM masses. Four scenarios were considered using the developed analytical model including SAHs using 0, 30, 60, 90 kg PCM. The obtained results illustrated that the maximum outlet temperature was reduced, approximately near 20 %, by increasing the PCM mass between 0 and 90 kg; however, heating time was extended to periods when solar energy availability was inadequate. The thermal performance improved by nearly 14.5 % in the SAH using 90 kg PCM mass compared to the SAH without using PCM. The thermal performance of the SAH with 90 kg PCM was slightly higher than the SAH using 30 kg of PCM; hence, a significant portion of stored thermal energy was lost during nighttime through heat exchange with ambient surroundings. The obtained results also showed that despite available latent thermal energy, the outlet air temperature profiles for the SAHs using different PCM mass were close after sunset due to the low thermal conductivity of paraffin.
Advanced Energy Technologies
Sibel Dursun; Ercan Aykut; Bahtiyar Dursun
Abstract
Somalia–Turkish Training and Research Hospital in Mogadishu, is only powered by diesel generator currently. In this paper, the energy demand of this hospital is utilized by determining the optimum hybrid renewable energy generating system. By HOMER, a sensitivity analysis has been made with emphasis ...
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Somalia–Turkish Training and Research Hospital in Mogadishu, is only powered by diesel generator currently. In this paper, the energy demand of this hospital is utilized by determining the optimum hybrid renewable energy generating system. By HOMER, a sensitivity analysis has been made with emphasis on three significant variables such as average wind speed, present diesel price, and solar radiation. From the results, it can be said that an optimum system is the standalone wind-diesel-battery storage Hybrid Renewable Energy System (HRES) with the configuration of 1,000 kW wind turbine, 350 kW diesel generator, 250 kW power converters, and 300 batteries. Additionally, the net present cost of the optimum system is calculated to be $5,056,700 and its cost of energy is estimated to be 0.191 $/kWh. The present cost of energy for Somalia is 0.5 $/kWh. This shows that the energy cost for the proposed HRES is cheaper than the conventional one. Lastly, according to the results, it is clear that the wind–diesel–battery storage HRES seems more environment friendly than other HRESs.
Advanced Energy Technologies
Payam Ghorbannezhad; Maryam Abbasi
Abstract
Fast pyrolysis of sugarcane bagasse was investigated in a tandem micro-pyrolyzer. The effects of temperature and particle size on the phenolic compounds and hemicellulose products distribution were examined during fast pyrolysis process. For this, changes in the micro-reactor parameters were made (particle ...
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Fast pyrolysis of sugarcane bagasse was investigated in a tandem micro-pyrolyzer. The effects of temperature and particle size on the phenolic compounds and hemicellulose products distribution were examined during fast pyrolysis process. For this, changes in the micro-reactor parameters were made (particle size between 0.1 and 0.5 mm and reactor temperature between 450 and 600 °C). Response Surface Methodology (RSM) was used to optimize pyrolysis parameters. The results indicated that the temperature had the highest effect on phenolic and furfural-type compounds, whereas the particle size did not exhibit significant effects on carboxylic acid products. The largest number of phenolic compounds were achieved upon decreasing the temperature and increasing particle size. The ANOVA analysis revealed that the full quadratic model was more adequate for phenolic and furfural compounds, whereas the linear square model was accurate for carboxylic acids. In general, a tandem micro-pyrolyzer interfacing with a GC-MS analysis facilitated a better understanding of a chemical composition of biomass and therefore, could remarkably improve the valorising of sugarcane bagasse application in biorefinery processes.
Advanced Energy Technologies
Tuhid Pashaee Golmarz; Sajadollah Rezazadeh; Maryam Yaldagard; Narmin Bagherzadeh
Abstract
In the present work, a Proton-Exchange Membrane Fuel Cell (PEMFC) as a three-dimensional and single phase was studied. Computational fluid dynamics and finite volume technique were employed to discretize and solve a single set of flow fields and electricity governing equations. The obtained numerical ...
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In the present work, a Proton-Exchange Membrane Fuel Cell (PEMFC) as a three-dimensional and single phase was studied. Computational fluid dynamics and finite volume technique were employed to discretize and solve a single set of flow fields and electricity governing equations. The obtained numerical results were validated with valid data in the literature and good agreement was observed between them. The main purpose of this paper is to investigate the effect of deformation of the geometric structure of a conventional cubic fuel cell into a cylindrical one. For this purpose, some important parameters indicating the operation of the fuel cell such as oxygen distribution, water, hydrogen, proton conductivity of the membrane, electric current density, and temperature distribution for two voltage differences between the anode and cathode and the proposed models were studied in detail. Numerical results showed that in the difference of voltages studied, the proposed new model had better performance than the conventional model and had a higher current density, in which at V = 0.4 [V], about a 10.35 % increase in the amount of electric current density was observed and the average increment in generated power was about 8 %, which could be a considerable value in a stack of cells. Finally, the discussion of critical parameters for both models was presented in more detail. The core idea of the results is that the Oxygen and Hydrogen utilization, water creation, and heat generation are greater in the new model.
Advanced Energy Technologies
Abubakari Zarouk Imoro; Moses Mensah; Richard Buamah
Abstract
This study was conducted to improve the voltage production, desalination, and COD removal efficiencies of a five-chamber Microbial Desalination Cell (MDC). To do this, rhamnolipid was added to anolytes only and catholytes stirred to determine the effects of these factors on the MDC activity. This was ...
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This study was conducted to improve the voltage production, desalination, and COD removal efficiencies of a five-chamber Microbial Desalination Cell (MDC). To do this, rhamnolipid was added to anolytes only and catholytes stirred to determine the effects of these factors on the MDC activity. This was followed by a factorial study to investigate the effects of the interactions of rhamnolipid and stirring on the voltage production, desalination, and COD removal efficiencies of the MDC. Increasing the concentration of rhamnolipid to 240 mg/L improved the peak voltage produced from 164.50 ± 0.11 to 623.70 ± 1.32 mV. Also, the desalination efficiency increased from 20.16 ± 1.97 % when no rhamnolipid was added to 24.89 ± 0.50 % at a rhamnolipid concentration of 240 mg/L, and COD removal efficiency increased from 48.74 ± 8.06 % to 64.17 ± 5.00 % at a rhamnolipid concentration of 400 mg/L. In the stirring experiments, increasing the number of stirring events increased peak voltage from 164.50 ± 0.11 to 567.27 ± 18.06 mV. Similarly, desalination and COD removal efficiencies increased from 20.16 ± 1.97 % and 48.74 ± 8.06 % to 24.26 ± 0.97 % and 50.23 ± 1.60 %, respectively, when the number of stirring events was more than twice a day. In the factorial study, voltage production, desalination, and COD removal efficiencies were 647.07 mV, 25.50 %, and 68.15 %, respectively. However, the effect of the interaction between rhamnolipid and stirring was found to be insignificant (p>0.05). Thus, the addition of only rhamnolipid or the stirring of catholytes only can improve the performance of the five-chamber MDC.
Advanced Energy Technologies
Mahnoosh Eghtedari; Abbas Mahravan
Abstract
Increasing fossil fuel consumption in the building, especially in the air-conditioning sector, has increased environmental pollution and global warming. In this research, a zero-energy passive system was designed to ventilate the building and provide comfortable conditions for people in the summer. A ...
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Increasing fossil fuel consumption in the building, especially in the air-conditioning sector, has increased environmental pollution and global warming. In this research, a zero-energy passive system was designed to ventilate the building and provide comfortable conditions for people in the summer. A hybrid passive system was designed for indoor cooling to minimize fossil energy use. This research was done experimentally- and analytically and by simulation. An experimental study comprising a test chamber and simulation using Builder Design software was carried out to evaluate the cooling and ventilation potential of a hybrid passive system functioning. In the experimental section, air temperature, humidity, and airflow for the outdoor environment and the output of the evaporative cooling channel were measured. These measurements were tested in August from 9:00 AM to 3:00 PM for six consecutive days. The obtained experimental data were given to Design Builder software as an input parameter, and then, the comfort conditions inside the chamber, the dimensions, and location of the air inlet valve into the chamber were examined. The findings showed that the proposed system could reduce the air temperature by an average of 10 oC and increase the air humidity by 33 %. The findings showed that the air inside the chamber was comfortable during the hottest hours of the day. Raising the valve location, increasing the area, and increasing the volumetric flow rate of the air increased the percentage of dissatisfaction. The findings showed that in addition to wind speed and air temperature, the geometrical shape of the air inlet opening contributes to indoor air comfort conditions.
Advanced Energy Technologies
Leila Samiee; Fatemeh Goodarzvand-Chegini; Esmaeil Ghasemikafrudi; Kazem Kashefi
Abstract
Some chemical processes, like the chlor-alkali industry, produce a considerable amount of hydrogen as by-product, which is wasted and vented to the atmosphere. Hydrogen waste can be recovered and utilized as a significant clean energy resource in the processes. This paper describes the thermodynamic ...
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Some chemical processes, like the chlor-alkali industry, produce a considerable amount of hydrogen as by-product, which is wasted and vented to the atmosphere. Hydrogen waste can be recovered and utilized as a significant clean energy resource in the processes. This paper describes the thermodynamic analysis of hydrogen recovery at an industrial chlor-alkali plant by installation of hydrogen boiler and alkaline fuel cell. In addition, emission reduction potentials for the proposed systems were estimated. However, the goal of this work is to analyze the techno-economic feasibility and environmental benefits of using utilization systems of hydrogen waste. The results showed that hydrogen boiler scenario could produce 28 ton/hr steam at pressure of 25 bar and temperature of 245 °C, whereas the alkaline fuel cell system could produce 7.65 MW of electricity as well as 3.83 m3/h of deionized water based on the whole surplus hydrogen. In comparison, the alkaline fuel cell scenario has negative IRR (Internal Return Rate) and NPV (Net Present Value) due to cheap electricity and high cost of capital investment. However, regarding the steam price, the hydrogen boiler project has reasonable economic parameters in terms of IRR and NPV. Therefore, the hydrogen recovery scenario is proposed to install a hydrogen boiler as a feasible and economic idea for steam production in our case. Furthermore, in terms of emission reduction, hydrogen boiler and alkaline fuel cell techniques can significantly reduce greenhouse gas emission by 49300 and 58800 tons/year, respectively, whereas other pollutants can also be reduced by 141 and 95 tons/year in hydrogen boiler and alkaline fuel cell scenarios, respectively.
Advanced Energy Technologies
Masoumeh Javaheri; Noushin Salman Tabrizi; Amir Rafizadeh
Abstract
Given that the catalyst and catalyst support properties have a key role to play in the electrochemical activity of fuel cells, in this research, the synergism effect of Pt and Ru nanoparticles reduced on catalyst support [synthesized Carbon Aerogel-Carbon Nanotube (CA-CNT)] was investigated. The catalyst ...
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Given that the catalyst and catalyst support properties have a key role to play in the electrochemical activity of fuel cells, in this research, the synergism effect of Pt and Ru nanoparticles reduced on catalyst support [synthesized Carbon Aerogel-Carbon Nanotube (CA-CNT)] was investigated. The catalyst support was synthesized by sol-gel method and the catalyst nanoparticles were reduced on catalyst support using impregnation and hydrothermal method. Different molar ratios of Pt:Ru (i.e., 0:1, 1:0, 3:1, 2:1, 1:1, 1:2, and 1:3) were applied as electrocatalysts for Methanol Oxidation Reaction (MOR). The electrochemical performance of these catalysts was compared with that of commercial Pt/C (20 % wt) for MOR. The physical properties of the synthesized catalyst support (CNT-CA) were studied using FESEM and BET techniques. Moreover, XRD and ICP analyses were employed for investigating each of the synthesized catalyst (Pt/CNT-CA and Ru/CNT-CA). The cyclic voltammetry and chronoamperometry methods were used to conduct electrochemical analysis. Research results indicated that synthesis methods were reliable. Moreover, CNT-CA had a proper performance as the catalyst support and the Pt:Ru with a 3:1 molar ratio was the best catalyst among all the synthesized catalysts for MOR.
Advanced Energy Technologies
Ghazanfar Shahgholian
Abstract
Renewable energy provides twenty percent of electricity generation worldwide. Hydroelectric power is the cheapest way to generate electricity today. It is a renewable source of energy and provides almost one-fifth of electricity in the world. Also, it generates electricity using a renewable natural resource ...
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Renewable energy provides twenty percent of electricity generation worldwide. Hydroelectric power is the cheapest way to generate electricity today. It is a renewable source of energy and provides almost one-fifth of electricity in the world. Also, it generates electricity using a renewable natural resource and accounting for six percent of worldwide energy supply or about fifteen percent of the world’s electricity. Hydropower is produced in more than 150 countries. Hydropower plant producers provide energy due to moving or falling water. This paper presents and discusses studies on hydroelectric power plant fields, which have been carried out by different investigators. This work aims to study and provide an overview of hydroelectric power plants such as applications, control, operation, modeling and environmental impacts. Also, the hybrid power and efficiency of the hydroelectric power plants has been investigated. The applications of a flexible AC transmission system (FACTS) controller in the power system with the hydroelectric power plants are presented.
Advanced Energy Technologies
Nima Amani
Abstract
Must limited energy resources and the need for energy saving make the design of buildings more efficient in terms of energy consumption. For this reason, proper orientation of buildings, use of sunlight, natural ventilation, application of consumable materials are factors that help reduce heat and cooling ...
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Must limited energy resources and the need for energy saving make the design of buildings more efficient in terms of energy consumption. For this reason, proper orientation of buildings, use of sunlight, natural ventilation, application of consumable materials are factors that help reduce heat and cooling loads. The objective of this study is to evaluate the energy efficiency of residential buildings using natural energy and optimizing the choice of materials for heat and cold saving with the Ecotect simulation software. According to analysis and simulation, it was found that the optimum materials of the main building components in a mild climate zone of Rasht city include (a) the Brick Conc block Plaster for a wall with the total radiation incident of 340 W/m2 and a radiation absorption of 240 W/m2, (b) Double Glazed-Low E for windows with the total radiation incident of 340 W/m2 and a radiation absorption of 100 W/m2, (c) Foam Core Ply Wood for door with the total radiation incident of 340 W/m2 and a radiation absorption of 200 W/m2, (d) ConcSlab- OnGround for floor with the total radiation incident of 340 W/m2 and a radiation absorption of 220 W/m2, and (e) Conc Roof Asphalt for roof with the total radiation incident of 340 W/m2 and a radiation absorption of 300 W/m2. According to an hourly temperature analysis of all stories of the building on two hot and cold days of the year and as observed by the design and material selection requirements, the building will be conditioned in an almost thermal comfort zone (below 30 degrees) in the warm season.
Advanced Energy Technologies
Mahdi Shakouri; Alireza Noorpoor; Hossein Ghadamian
Abstract
This study presents an analytical method for quantifying the improvement of thermal energy performance of a building integrated photovoltaic double-skin façade. The system was suggested as a retrofit measure for an existing building in Tehran. The effect of thermal performance was analyzed through ...
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This study presents an analytical method for quantifying the improvement of thermal energy performance of a building integrated photovoltaic double-skin façade. The system was suggested as a retrofit measure for an existing building in Tehran. The effect of thermal performance was analyzed through computer-assisted developed codes using Engineering Equation Solver (EES) software. Three scenarios were defined and for each scenario, temperature and velocity profiles were provided through continuity, momentum, and energy equations. Given that the monocrystalline photovoltaic modules and the double-glazed windows are quite common in the current condition in Tehran, the authors considered them for analysis. A comparison of results is valuable for those cases that intend to select either glass or photovoltaic as the outer façade. The quantitative results illustrate that the proposed system would reduce the cooling demand in the summer case by 18.5 kilowatts, which is around 8.7 percent of the current cooling load. According to the results of the sensitivity analysis, both glass and photovoltaic façades were of greater efficiency in terms of energy saving in the summer. By increasing the ratio between the photovoltaic outer façade to the surface area of the glass section, the amount of energy saving due to the total cooling load reduction will increase. The results of the analysis showed that the application of the suggested system would reduce the thermal load by 2.1 percent in the winter season.
Advanced Energy Technologies
Fatemeh Boshagh; Khosrow Rostami
Abstract
The current review purpose is to present a general overview of different experimental design methods that are applied to investigate the effect of key factors on dark fermentation and are efficient in predicting the experimental data for biological hydrogen production. The methods of two levels full ...
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The current review purpose is to present a general overview of different experimental design methods that are applied to investigate the effect of key factors on dark fermentation and are efficient in predicting the experimental data for biological hydrogen production. The methods of two levels full and fractional factorials, Plackett–Burman, and Taguchi were employed for screening the most important factors in dark fermentation. The techniques of central composite, Box–Behnken, Taguchi, and one factor at a time for optimization of the dark fermentation were extensively used. Papers on the three levels full and fractional factorials, artificial neural network coupled with genetic algorithm, simplex, and D-optimal for the optimization of the dark fermentation are limited, and no paper on the Dohlert design has been reported to date. The artificial neural network coupled with genetic algorithm is a more suitable method than the RSM technique for the optimization of dark fermentation. Literature shows that the optimization of critical factors plays a significant role in dark fermentation and is useful to improve the hydrogen production rate and hydrogen yield.
Advanced Energy Technologies
Sadegh Safari; Hassan Ali Ozgoli
Abstract
In this paper, an electrochemical model was developed to investigate the performance analysis of a Solid Oxide Fuel Cell (SOFC). The curves of voltage, power, efficiency, and the generated heat of cell have been analyzed to accomplish a set of optimal operating conditions. Further, a sensitivity analysis ...
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In this paper, an electrochemical model was developed to investigate the performance analysis of a Solid Oxide Fuel Cell (SOFC). The curves of voltage, power, efficiency, and the generated heat of cell have been analyzed to accomplish a set of optimal operating conditions. Further, a sensitivity analysis of major parameters that have a remarkable impact on the economy of the SOFC and its residential applications has been conducted. The results illustrate that the current density and cell performance temperature have vital effects on the system efficiency, output power and heat generation of cell of the SOFC. The best system efficiency is approached up to 53.34 % while implementing combined heat and power generation might be further improved up to 86 %. The economic evaluation results indicate that parameters such as overall efficiency, natural gas price and additional produced electricity that has prone to be sold to the national power grid, have a significant impact on the SOFC economy. The results indicate the strong reduction in the purchasing cost of the SOFC, i.e. not more than $2500, and improving the electrical efficiency of SOFC, i.e. not less than 42 %, can be the breakeven points of investment on such systems in residential applications. Also, it is found that the target of this SOFC cogeneration system for residential applications in Iran is relying on considerable technological enhancement of the SOFC, as well as life cycle improvement; improvement in governmental policies; and profound development in infrastructures to mitigate legal constraints.
Advanced Energy Technologies
Azin Hasanvand; Mehdi Pourabdoli; Ahmad Ghaderi Hamidi
Abstract
The effect of Al2O3 (1-10 wt %) and Y2O3 (1-10 wt %) additions on thermochemical heat storage properties of Co3O4/CoO system was investigated by thermogravimetry, XRD, and SEM analyses. Results showed that the addition of Al2O3 to Co3O4 at constant 8 h mechanical activation improved the redox cycle stability ...
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The effect of Al2O3 (1-10 wt %) and Y2O3 (1-10 wt %) additions on thermochemical heat storage properties of Co3O4/CoO system was investigated by thermogravimetry, XRD, and SEM analyses. Results showed that the addition of Al2O3 to Co3O4 at constant 8 h mechanical activation improved the redox cycle stability and increased oxygen sorption value and rate. It was found that oxygen sorption and their rate decreased with increasing the alumina content to more than 8 wt %. The formation of the spinel phase and an increase in its amount by increasing the alumina content led to a decrease in the oxygen sorption capacity. SEM studies showed that Al2O3 prevented the sintering and particle growth of cobalt oxide particles during reduction and re-oxidation processes. In addition, results showed that the addition of Y2O3 in all ranges to Co3O4 improved the redox cycle stability of cobalt oxide; however, it significantly decreased the oxygen sorption in the Co3O4/CoO system. XRD patterns of a sample containing 10 wt % yttria before the redox process indicated the presence of only Co3O4 phase; however, after three redox cycles, other phases including CoO and Y2O3 appeared.
Advanced Energy Technologies
Haleh Sadeghi; Iraj Mirzaei; Shahram Khalilaria; Sajad Rezazadeh; Mojtaba Rasouli Gareveran
Abstract
Among the renewable energy systems, fuel cells are of special significance about which more investigation is required. The principal goal of the present study is considering the effect of the geometry change on the fuel cell's performance. In this paper, a three-dimensional model of proton exchange membrane ...
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Among the renewable energy systems, fuel cells are of special significance about which more investigation is required. The principal goal of the present study is considering the effect of the geometry change on the fuel cell's performance. In this paper, a three-dimensional model of proton exchange membrane fuel cell has been numerically simulated with conventional cubic geometry. Afterwards, two brand-new cylindrical models have been proposed to compare and select the best model. The governing equations include mass, momentum, energy, species and electrical potential, which are discretized and solved using the method of computational fluid dynamics. The results obtained from numerical analyses were validated with those from experimental data, which showed acceptable agreement. For the above-mentioned models, changes in the species mass fraction, temperature, electric current density, and over-potential were analyzed in more detail. The results reveal that, in all three models, by decreasing the amount of cell voltage differences between the anode and the cathode, higher current density is produced, which leads to high input species consumption and, consequently, more water and heat generation. On the other hand, the four-channel cylindrical model is more efficient than the other two models and has shower pressure drop due to its shorter pathway. The results illustrated that, at V=0.6 )V(, the amount of the output current density in the four-channel model increased by approximately 18.4 %, compared to that in the other two models. Further, in this model, the material used in bipolar plates is less than that in the other models.
Advanced Energy Technologies
Ali Mostafaeipour; Mojtaba Qolipour; Hossein Goudarzi; Mehdi Jahangiri; Amir-Mohammad Golmohammadi; Mostafa Rezaei; Alireza Goli; Ladan Sadeghikhorami; Ali Sadeghi Sedeh; Seyad Rashid Khalifeh Soltani
Abstract
Fuel cells are potential candidates for storing energy in many applications; however, their implementation is limited due to poor efficiency and high initial and operating costs. The purpose of this research is to find the most influential fuel cell parameters by applying the adaptive neuro-fuzzy inference ...
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Fuel cells are potential candidates for storing energy in many applications; however, their implementation is limited due to poor efficiency and high initial and operating costs. The purpose of this research is to find the most influential fuel cell parameters by applying the adaptive neuro-fuzzy inference system (ANFIS). The ANFIS method is implemented to select highly influential parameters for proton exchange membrane (PEM) element of fuel cells. Seven effective input parameters are considered including four parameters of semi-empirical coefficients, parametric coefficient, equivalent contact resistance, and adjustable parameter. Parameters with higher influence are then identified. An optimal combination of the influential parameters is presented and discussed. The ANFIS models used for predicting the most influential parameters in the performance of fuel cells were performed by the well-known statistical indicators of the root-mean-squared error (RMSE) and coefficient of determination (R2). Conventional error statistical indicators, RMSE, r, and R2, were calculated. Values of R2 were calculated as of 1.000, 0.9769, and 0.9652 for three different scenarios, respectively. R2 values showed that the ANFIS could be properly used for yield prediction in this study