Advanced Energy Technologies
Mina Bahraminasab; Hamed Moqtaderi; Atiyeh Kiaeinejad
Abstract
Microbial Fuel Cells (MFCs) represent an environmentally-friendly approach to generating electricity, but the need to study variation parameters to find improvement conditions has been an important challenge for decades. In this study, a single-chamber MFC was designed to investigate the key parameters ...
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Microbial Fuel Cells (MFCs) represent an environmentally-friendly approach to generating electricity, but the need to study variation parameters to find improvement conditions has been an important challenge for decades. In this study, a single-chamber MFC was designed to investigate the key parameters such as the concentration and type of bacteria, chamber temperature, electrode spacing, and substrate rotation speed that affected the performance of MFCs. Therefore, two types of bacteria, Shewanella oneidensis (S.one) and Escherichia coli (E. coli), were compared as microorganisms. Then, the function of MFC was investigated under the following condition: three temperatures (30 ℃, 45℃, and 60℃), three bacterial concentrations (0.5% (v/v) (4.5 mg/ml), 1% (v/v) (9mg/ml), and 1.5% (v/v) (13.5mg/ml)), electrode distances (2 cm, 3 cm, 4cm), and substrate speeds (100 rpm, 150 rpm, 200 rpm). Ultimately, (S.one) bacteria, a chamber temperature of 45 ℃, a bacterial concentration of 1% (v/v) (9mg/ml), a cathode-anode spacing of 3 cm, and a rotation speed of 150 rpm proved to be the most efficient parameter settings for the constructed microbial fuel cell. The maximum voltage and highest power density were 486.9 mV and 9.73 mW/ , respectively, with a resistance of 7500 ohms. These results are meaningful for determining and improving important parameters in an MFC device.
Advanced Energy Technologies
Shafini Mohd Shafie; Zakirah Othman; A. Harits Nu'man; Nik Nurul Anis Nik Yusuf
Abstract
Penetration of renewable energy in the energy generation mix must be viewed from different angles. This issue shall not only cover the technological part, but also economic, environmental, and social criteria. The fuel cell provides huge potential with less reliance on fossil fuel-based electricity generation. ...
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Penetration of renewable energy in the energy generation mix must be viewed from different angles. This issue shall not only cover the technological part, but also economic, environmental, and social criteria. The fuel cell provides huge potential with less reliance on fossil fuel-based electricity generation. This paper aims to model the optimum design of fuel cell-based electricity generation in Malaysia. Economic and environmental aspects are indicators that contribute to designing an optimum model. Both Multi-Criteria Analysis and Analytic Hierarchy Process were employed in order to decide on the optimum site for the system. Truck transportation, biogas storage, and fuel cell system are among the most important criteria that provide final weighted criteria. Considering both criteria for the economic and environment concerns, the best optimum location is in Sarawak State. The findings of this study influence the decision-making and help researchers and decision-makers develop proper strategies in the renewable energy roadmap.
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
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
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
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
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
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
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
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.