Zahra Hajabdollahi; Majid Sedghi Dehnavi; Hassan Hajabdollahi
Abstract
Thermal modelling and optimal design of a solar absorption cooling system are presented, and hourly analysis is performed over the period of a year. Three design parameters are considered, then the Real Parameter Genetic Algorithm (RPGA) is applied to obtain the minimum total annual cost. The optimization ...
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Thermal modelling and optimal design of a solar absorption cooling system are presented, and hourly analysis is performed over the period of a year. Three design parameters are considered, then the Real Parameter Genetic Algorithm (RPGA) is applied to obtain the minimum total annual cost. The optimization results show that the solar cooling optimum configuration needs 1630 square meter collectors, a storage tank with a 15000L capacity as well as an absorption chiller with 300kW capacity. The hourly analysis shows that the space temperature fluctuates on average every 62 minutes during June and decreases to 51 minutes in September. In addition, the optimum number of collectors increases 26.67% given a 50% increment in electricity price while it decreases 20% given a 50% decrement in electricity price. Finally a sensitivity analysis on RPGA parameters is performed and results are reported.
Renewable Energy Resources and Technologies
Hasan Huseyin Coban
Abstract
This paper focuses on the short-term cascade hydro scheduling problem, especially in a competitive environment, namely in market conditions. A nonlinear stochastic optimization method is proposed to take into consideration the hydroelectric energy production as a function of hourly electricity market ...
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This paper focuses on the short-term cascade hydro scheduling problem, especially in a competitive environment, namely in market conditions. A nonlinear stochastic optimization method is proposed to take into consideration the hydroelectric energy production as a function of hourly electricity market prices and water release rates. In order to solve a case study based on one of the Turkish cascaded hydropower facilities, the proposed method has been successfully applied to a wide variety of problems at a negligible computation time while providing a higher profit. The paper shows the benefits that could be achieved by applying a model based on the Quasi-Newton Method, which finds zeroes or local maxima and minima of solving a certain type of optimization functions because it can better handle the uncertainty, constraints, and complexity of the problem. Ten-year hourly water inflow data and electricity market prices were used as inputs, and the results of the cascade and single optimization were compared. A comparison study with the operation of each hydropower plant (HPP) separately showed that 18 % higher income was obtained with a cascade variant.
Renewable Energy Resources and Technologies
Soheil Fathi; Abbas Mahravan
Abstract
In many middle- and high-income countries, existing buildings will occupy the majority of building areas by 2050 and measures are needed to upgrade the mentioned buildings for a sustainable transition. This research proposes a method to mitigate the energy consumption of existing educational buildings ...
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In many middle- and high-income countries, existing buildings will occupy the majority of building areas by 2050 and measures are needed to upgrade the mentioned buildings for a sustainable transition. This research proposes a method to mitigate the energy consumption of existing educational buildings using four energy efficiency measures (EEMs). The proposed method divides simulations into two main parts: simulations with and without using heating, ventilating, and air conditioning (HVAC) systems. Four passive EEMs are used, including window replacement, proposed shading devices, new insulations, and installing a new partition wall for the entrance part of the building. This research uses a simulation-based method to examine the effect of each EEM on the energy consumption of the building using DesignBuilder software. The steps of data collection and modeling in this research include collecting raw data related to the physical characteristics of the building experimentally and creating a basic model. Afterwards, simulation scenarios were defined based on the proposed method, and several simulations were carried out to examine the impact of each EEM on the energy performance of the building. Two environmental parameters of the simulation process, including indoor air temperature (IAT) and relative humidity (RH), were used. The measures reduced the heating and cooling demands in the building by 80.14 % and 15.70 %, respectively. Moreover, the results indicated that the total energy consumption of the building were reduced by 10.44 % after retrofitting measures.
Advanced Energy Technologies
Ala Moradi; Hajar Es-haghi; Seyed Hassan Hashemabadi; Majid Haghgoo; Zahra Emami
Abstract
Phase Change Materials (PCMs) have received much consideration as thermal energy storage systems due to their high storage capacity. However, their heat transfer rate is limited because of the low thermal conductivity. Incorporating of carbon-based nanoparticles into the matrix of PCMs with good dispersion ...
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Phase Change Materials (PCMs) have received much consideration as thermal energy storage systems due to their high storage capacity. However, their heat transfer rate is limited because of the low thermal conductivity. Incorporating of carbon-based nanoparticles into the matrix of PCMs with good dispersion can be an efficient way to solve their deficiency. In this research, graphite nanoparticles were homogeneously dispersed within the Eicosane PCM matrix to prepare a Nano-Enhanced PCM (NEPCM). The main objective is to determine the optimum amount of graphite to maximize the thermal properties of NEPCM composites. The Scanning Electron Microscopy (SEM) images of the prepared nanocomposites confirmed the excellent dispersion of graphite nanoparticles within the Eicosane layers through an ultrasonic bath-assisted homogenization procedure followed by solidification. In addition, Differential Scanning Calorimetry (DSC) and Thermal Conductivity Evaluation (TC) of the samples were conducted to determine their heat capacity and thermal diffusivity. The results illustrated that the more the number of graphite nanoparticles, the larger the number of collisions between graphite and Eicosane. As the nanoparticle content increased, the thermal conductivity and diffusivity were enhanced, as well. Numerically, the maximum thermal conductivity was 4.1 W/m K for the composite containing 10 wt% graphite, 15.66 times that of the pure Eicosane. Furthermore, increasing crystal growth and reducing heat capacity for the large number of nanoparticles in the composite were discussed. The significantly improved thermal properties of the prepared NEPCMs with an optimal nanoparticle content could make them applicable for different thermal management applications.
Javad Faiz; Arash Hakimi Tehrani; Ghazanfar shahgholian; Amir Masoud Takbash
Abstract
Pitch control is one of t he major aspects of wind turbine control, particularly over high wi nd s p e e d a n d oscillations. General El e c t r i c (GE) model of wi n d t ur bi ne i s practically compatible with the structure of the wind turbines. I t ...
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Pitch control is one of t he major aspects of wind turbine control, particularly over high wi nd s p e e d a n d oscillations. General El e c t r i c (GE) model of wi n d t ur bi ne i s practically compatible with the structure of the wind turbines. I t h a s b e e n p r o v e d t h a t simulation results using this model are closer to the actual case, compared to other available models. Therefore, in this paper the GE model is used to evaluate the eff ectiveness of three different controllers including Fuzzy controller, self-organized Fuzzy controller (SOFC) and PI controller i n pitch control of the wi nd turbine. Afterward, the results of the controller applications as well as the no controller case in t h e pitch control are compared. The results show a better performance of SOFC in damping the oscillations and overshoot of the wind turbine shaft speed. Finally,electrical power limit and converter cost, the economic analysis of pitch controller application are carriedout. It is shown that the application of the SOFC results are around $142,646 saving.
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.
Environmental Impacts and Sustainability
Marziyeh Forootan; Bahram Hosseinzadeh Samani; Amin Lotfalian; Sajad Rostami; Zahra Esmaeili; Marziyeh Ansari Samani
Abstract
To preserve fossil fuel sources and reduce environmental pollution, it is necessary to use higher quality and more efficient fuels that cause lower pollution and are recovered more easily. Therefore, this study will investigate the cycle of biodiesel production from chicken fat by life-cycle assessment ...
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To preserve fossil fuel sources and reduce environmental pollution, it is necessary to use higher quality and more efficient fuels that cause lower pollution and are recovered more easily. Therefore, this study will investigate the cycle of biodiesel production from chicken fat by life-cycle assessment (LCA). To achieve this purpose, information on the amount of inputs consumed and produced by some broiler-farming units was collected using questionnaire. The value of net energy in this cycle was assessed to be a large negative number, and the energy ratio lower than one indicates high energy consumption of the production of this fuel. The net yield of biodiesel production was 0.574 liter-biodiesel per kg of waste fat. In the cycle, the greatest impact of pollutants was exerted on the Marine aquatic ecotoxicity intoxication and the least effect on ozone depletion. According to the global warming index, production of 1 liter of biodiesel yielded 1.90 kg CO2, and the depletion rate of fossil fuel sources for the production of 1 liter of biodiesel was obtained 21.35 MJ. The production of biodiesel from chicken slaughterhouse waste fat is considered a kind of energy recycling and is an effort to reduce environmental pollution.
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.
Renewable Energy Resources and Technologies
Hadi Farzan
Abstract
The present study investigates the effectiveness of thermostat control strategy in cooling energy consumption in residential buildings. To evaluate the energy consumption, two scenarios including a residential zone with and without the thermostat control system are assumed. The TRNSYS software provides ...
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The present study investigates the effectiveness of thermostat control strategy in cooling energy consumption in residential buildings. To evaluate the energy consumption, two scenarios including a residential zone with and without the thermostat control system are assumed. The TRNSYS software provides an efficient numerical tool to model and evaluate a cooling system. Furthermore, since solar-powered cooling systems for residential air-conditioning are receiving growing and significant interest, a hot-water fired absorption chiller coupled with evacuated tube collectors is considered as the cooling system. The results reveal that the cooling systems consume a large amount of energy in hot climate zones without employing the thermostatic control. Therefore, cooling energy has great potential for a significant saving in hot climates. It is illustrated that the thermostat strategy has an obvious impact on such energy saving. In the current study, employing the thermostat in 90m2 residential building results in saving energy by up to 36%.
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.
Renewable Energy Resources and Technologies
Alireza Shirneshan; Bahram Hosseinzadeh Samani
Abstract
In this study, the effects of JP-4-biodiesel-diesel blends and engine operating parameters on the performance characteristics of a diesel engine were investigated. The experimental tests were performed on a four-cylinder DI diesel engine. The Mixture-RSM method was applied to develop the mathematical ...
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In this study, the effects of JP-4-biodiesel-diesel blends and engine operating parameters on the performance characteristics of a diesel engine were investigated. The experimental tests were performed on a four-cylinder DI diesel engine. The Mixture-RSM method was applied to develop the mathematical models based on the experimental data. The results showed that the fitted models could be properly applied to predict the performance characteristics of the engine. According to the results, the brake power and torque decreased with increasing the biodiesel amount in the fuel mixture due to the lower energy content and higher viscosity of biodiesel than diesel fuel No.2. However, the brake power and torque increased slightly with increasing JP-4 in the fuel blend. The results also indicated that the BSFC increased with the higher proportion of biodiesel in the mixture at all engine speeds. The results indicated that there was no considerable difference in BSFC values while JP-4 was added to the fuel mixture, especially at higher engine speeds. Moreover, the difference of brake power values for fuel blends included biodiesel and neat diesel decreases at higher engine speeds due to the positive role of oxygen content in the molecular structure of biodiesel. Based on the results, brake power and torque increased at the higher engine load as a result of higher temperatures and better combustion conditions. Moreover, JP-4 caused an improvement in brake thermal efficiency compared to biodiesel, especially at lower and medium engine speeds. Generally, it is indicated that the application of JP-4 can improve engine performance.
Parisa Raeisi Mahdi Abadi; Shabnam Vahdati Daneshmand; Reza Sharifi
Abstract
High costs, unreliable resources for long term use and extensive negative impact on our environment are such problems associated with traditional sources of energy and fossil fuels which make us move toward implementation of renewable sources of energy. Fossil fuel pollution and reserve depletion in ...
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High costs, unreliable resources for long term use and extensive negative impact on our environment are such problems associated with traditional sources of energy and fossil fuels which make us move toward implementation of renewable sources of energy. Fossil fuel pollution and reserve depletion in oil producing countries caused by increasing demands, make wind energy an attractive source of energy in the future. Renewable energy sources are expected to have an important role in many countries as well as Iran and would be flourished in near future. In this study we aim to offer economic evaluation of wind turbine installation for chabahar in southeastern part of Iran. This study evaluates the economic feasibility of electricity generation using wind turbines in Chabahar - Iran situated in the Southeast part of Iran. All analyzes were performed by Homer software and local weather information and software provided by NASA Weather Homer is used. In this study 5 MW wind turbine with INVELOX technology is used .The analysis results show that Annual average of wind speed is 4.11 m/s at a Height of 10 m and 905 Gwh is the average of annual energy production, the cost of energy is calculated of 2.3 cents/kwh.
Environmental Impacts and Sustainability
Davar Rezakhani; Abdol Hamid Jafari; Mohammad Ali Hajabassi
Abstract
The application of nanomaterials to concrete is an innovative approach to enhance mechanical properties and durability performances. In this work, the addition of a combination of Graphene Oxide Nano-Platelets (GONP) and Ground Granulated Blast Furnace Slag (GGBFS) was studied as admixture in concrete. ...
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The application of nanomaterials to concrete is an innovative approach to enhance mechanical properties and durability performances. In this work, the addition of a combination of Graphene Oxide Nano-Platelets (GONP) and Ground Granulated Blast Furnace Slag (GGBFS) was studied as admixture in concrete. Tests on mechanical and chloride permeation properties were conducted. The results showed that the mix with 0.05 % GONP and the mix with 30 % GGBFS obtained better mechanical strength than the rest of the mixes. The highest electrical resistivity was achieved for the 90-day cured sample with 50 % GGBFS in CONP-free concrete and the 0.01 % GONP in GGBFS-free concrete, which was found to be the most effective in increasing concrete resistance to chloride permeation. The mix with 0.1 w % GONP and 50 w % GGBFS exhibited considerable performance even with other mechanical and durability performances. The addition of 0.1 % graphene oxide and 50 % granular slag increased the compressive strength of the concrete sample by 19.9 % during 28 days and 17.6 % during 90 days compared to the conventional concrete sample. Concrete with a combination of 0.1 % graphene oxide and 50 % granular slag experienced an increase in flexural strength by 15 % during 28 days and 13.6 % during 90 days. A significant reduction in electrical conductivity from 4012C to 1200C was observed for 90-day cured samples containing 0.1 wt % GO and 50 wt % GGBFS compared to the conventional sample. Response Surface Method (RSM) applied to the test data presented an optimized concrete mix containing 0.08 w % GONP and 50 w % GGBFS, the outcome of which was in close agreement with the experimental results.
Renewable Energy Economics, Policies and Planning
Ali Mostafaeipour; Afsaneh Nasiri
Abstract
In hot and dry regions, air conditioning is used for many different applications like residential, industry, and agriculture and dairy products. This research studies the applicability of wind and solar energies for cooling fruit storage warehouse in the hot and dry region of Yazd in Iran. The studied ...
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In hot and dry regions, air conditioning is used for many different applications like residential, industry, and agriculture and dairy products. This research studies the applicability of wind and solar energies for cooling fruit storage warehouse in the hot and dry region of Yazd in Iran. The studied case is a fruit warehouse with an area of 4240 m2 resulting in a storage capacity of about 1000 tons. For this purpose, the heat gain of the warehouse is determined, and the obtained cooling load is then used to examine the solar and wind energy to power a conventional warehouse system. Different scenarios are examined for this research such as solar air conditioner, solar absorption chiller, wind catcher, and a combination of solar air conditioners and solar absorption chiller for cooling the fruit warehouse. Comparison and economic evaluation of different scenarios show that the solar air conditioning ranks first for this purpose. Results are then validated using value engineering methodology. Solar air conditioning with the highest net present value (NPV) of 4,865,040,418 Rials and the best internal rate of return (IRR) value of 182.98 % was determined to be the best approach among the studied methods. The results of this research can be applied to other regions with similar climatic conditions too.
Renewable Energy Resources and Technologies
Alireza Maheri; I Kade Wiratama; Terence Macquart
Abstract
The effectiveness of trailing-edge flaps and microtabs in damping 1P-3P loads has been proven through a series of research work during the past decade. This paper presents the results of an investigation into the effectiveness of these devices in power enhancement and power control for responding to ...
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The effectiveness of trailing-edge flaps and microtabs in damping 1P-3P loads has been proven through a series of research work during the past decade. This paper presents the results of an investigation into the effectiveness of these devices in power enhancement and power control for responding to the issue of where these devices can be used with dual function of load and power control on a medium size turbine. The 300 kW-AWT27 wind turbine is used as the base wind turbine and the effects of adding trailing-edge flaps and string of microtabs of different lengths positioned at different span locations on the aerodynamic performance of the rotor are studied. In each case, the wind turbine simulator WTSim is used to obtain the aerodynamic performance measures. In the next step, the original blade twist is redesigned to ensure that the blade is optimized upon the addition of these active flow controllers. It is found that blades equipped with flaps can increase the annual average power and reduce the blade loading at the same time for constant speed and variable speed generators. Power enhancement is more visible on constant speed rotors, while load reduction is more significant on variable speed rotors. To achieve constant speed rotors, an average power enhancement of around 12 % is achieved for a flap of size 25 % of the blade span located at about 72 % of the blade span. Microtabs are less effective in power control and can improve the produced power only by a few percentage points.
Renewable Energy Resources and Technologies
Nikita Gupta; Mahajan Sagar Bhaskar; Sanjay Kumar; Dhafer J. Almakhles; Tarun Panwar; Abhinav Banyal; Aanandita Sharma; Akanksha Nadda
Abstract
The sun serves as the primary energy source, providing our planet with the essential energy for sustaining life. To efficiently harness this energy, photovoltaic cells, commonly known as PV cells, are employed. These cells convert the solar energy they receive into electrical energy. The operational ...
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The sun serves as the primary energy source, providing our planet with the essential energy for sustaining life. To efficiently harness this energy, photovoltaic cells, commonly known as PV cells, are employed. These cells convert the solar energy they receive into electrical energy. The operational point of the solar cell, delivering maximum output power, is referred to as the maximum power point (MPP). However, as light availability and temperature fluctuate throughout the day, the MPP also varies accordingly. To maintain constant operation at the MPP, Maximum Power Point Tracking (MPPT) algorithms are employed to trace the MPP during module operation. These algorithms can be categorized into four groups: classical, intelligent, optimization, and hybrid, based on the tracking algorithm utilized. Each MPPT algorithm, existing in these categories, comes with its own set of advantages and limitations. This paper extensively reviews fifteen algorithms categorized under different groups. The review concludes with a comparative analysis of these algorithms, considering various parameters such as cost, complexity, tracking accuracy, and sensed parameters in a succinct manner. The paper focuses on elucidating the necessity of MPPT algorithms, their classification as per existing literature, and a comparative assessment of the studied MPPT algorithms. This comprehensive review aims to address advancements in this field, paving the way for further research.
Ahmad Ali Pourbabaee; Mahdie Mondaniizadeh
Abstract
In this research, 11 yeast strains with ability to grow on petroleum sludge were isolated from effluent of a petroleum refinery. Based on growth on mineral media contaminated petroleum sludge, two isolates were selected as the super strains. Meanwhile, results based on biochemical and morphological experiments ...
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In this research, 11 yeast strains with ability to grow on petroleum sludge were isolated from effluent of a petroleum refinery. Based on growth on mineral media contaminated petroleum sludge, two isolates were selected as the super strains. Meanwhile, results based on biochemical and morphological experiments on the strains indicated that the two selected isolates belonged to Candida and Prototheca genus. Optimization with Taguchi Statistical Method (TSM) indicated that appropriate conditions for both isolates considering sludge concentrations, nitrogen source, pH, temperature and shaking rate (rpm) are equal to 10%, 2 g/l sodium nitrate, 6.5, 25°C and 190 rpm, respectively. Biomass production in optimal growing conditions for Candida and Prototheca were 1.54 g/l and 2.3 g/l, respectively. Gas Chromatography analyses of extracted fatty acids from supernatants and surface portions after methyl-esterifies with methanol: KOH solvents, indicated that content quantity of fatty acids on the surface was more than other portions and mainly in the forms of 16 and 18 saturated carbons and in the forms of palmitic acid and stearic acid. Therefore, these isolates can be used for recycling of petroleum sludge in production of yeast biomass and cell oil.
Renewable Energy Resources and Technologies
Sapna Kinattinkara; Thangavelu Arumugam; Nandhini Samiappan; Vivek Sivakumar; Sampathkumar Velusamy; Mohanraj Murugesan; Manoj Shanmugamoorthy
Abstract
Increased global energy consumption demands the use of more energy resources, aggravating environmental issues. This study focused on analyzing biogas production from a mixture of cow dung, water hyacinth, and food waste and checking the efficiency of the biogas. The efficiency of biogas production was ...
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Increased global energy consumption demands the use of more energy resources, aggravating environmental issues. This study focused on analyzing biogas production from a mixture of cow dung, water hyacinth, and food waste and checking the efficiency of the biogas. The efficiency of biogas production was tested using two alternative settings in the study. The first setup employs Eichhornia crassipes that have been NaOH-treated and mixed with co-digestion substrates such as cow manure and food waste which have been stored at room temperature for 32 days. The second setup contains five different types of substrates such as L1-cow dung, L2- cow dung: water hyacinth, L3-cow dung: food waste, L4-cow dung: water hyacinth: food waste, and L5-water hyacinth. The properties of the Eichhornia crassipes were studied on several biogas substrates, such as pH, temperature, COD, TOC, and NPK tests, as well as total biogas output and methane percentage. The results of the comparison analysis show that the substrate L4 has a high level of NPK (4.7 %) and a higher amount of COD (137600 mg/l). These characteristics enhance the gas yield and methane percentage (85 %). Overall, the water hyacinth mixed with cow dung and food waste exceeded the other four substrates. The total yield of biogas from the first setup was 8.5 litres, the flammability was tested on the 28th day, and the blue flame was obtained. Water hyacinth was removed from aquatic areas and used as an alternative energy source, hence being environmentally friendly.
Renewable Energy Resources and Technologies
Armin Motamed Sadr; Mehran Ameri Mahabadi; ٍٍEbrahim Jahanshahi Javaran
Abstract
In this research, the performance of an asphalt solar air collector was experimentally tested and the daily thermal and exergy efficiencies of the collector were analyzed. The sun's radiant energy is absorbed by asphalt and converted into thermal energy. Then, it is transmitted to aluminum pipes buried ...
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In this research, the performance of an asphalt solar air collector was experimentally tested and the daily thermal and exergy efficiencies of the collector were analyzed. The sun's radiant energy is absorbed by asphalt and converted into thermal energy. Then, it is transmitted to aluminum pipes buried under the asphalt and, finally, to the air passing through the pipes. A suction fan induces the ambient air to the collector. The experimental results show that the daily thermal efficiencies at mass flow rates of 0.007 (kg/s) and 0.014 (kg/s) are 11.98 % and 24.10 % and daily exergy efficiencies are 0.34 % and 0.66 %, respectively, showing the increase in daily energy and exergy efficiencies with increasing the air mass flow rate. In addition, results show that as the flow rate increases, the outlet air temperature decreases. The presence of temperature difference between the inlet and outlet of the collector in the last hours of the day, when the sun's radiation islow, indicates that asphalt acts as a thermal energy storage medium.
Ashkan Torkavannejad; S. Mehdi Pesteei; Farzin Ramin; Nima Ahmadi; Hadi Shahmohammadi
Abstract
In this research, the impact of shoulder width and geometry of gas channel with different structures on proton exchange membrane (PEM) has been investigated using numerical method. 3D, non-isothermal was used with single straight channel geometrywhile maintaining the same boundary conditions and reaction ...
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In this research, the impact of shoulder width and geometry of gas channel with different structures on proton exchange membrane (PEM) has been investigated using numerical method. 3D, non-isothermal was used with single straight channel geometrywhile maintaining the same boundary conditions and reaction area with addition of humidification for anode and cathode. Our study showed that an elliptical and circular channel cross-section gave higher current density as compared with conventional model. Moreover, the elliptical and circular channel configurations facilitated reactant transportation, caused more homogenous distribution of reactants andeffectively reduced mass transport loss, which lowered cathode overpotential of the cell which is the main cause of loss. Simulation of the three different channel geometries revealed that shoulder width has dominating effect on cell performance and leads to increase the value of Ohmicloss. The numerical model is validated against published experimental data and shows good agreement. Additional results with more detail are discussed and presented in the text.
John G Mbaka; Mercy. W. Mwaniki
Abstract
Small Hydro-power Plants (SHP) are an important source of electricity in many countries. However, little is known about SHP in Kenya. This paper reviews the status, challenges in implementation of SHP and prospects for future development of SHP in Kenya. The paper shows that SHP has not yet fully utilized ...
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Small Hydro-power Plants (SHP) are an important source of electricity in many countries. However, little is known about SHP in Kenya. This paper reviews the status, challenges in implementation of SHP and prospects for future development of SHP in Kenya. The paper shows that SHP has not yet fully utilized the available hydro-power potential. The challenges associated with SHP development should be addressed to realize its full hydro-power generation potential in the future.
Ehsan Hosseini; Ghazanfar Shahgholian
Abstract
The most common controller in wind turbine is the blade pitch angle control in order to get the desired power. Controlling the pitch angle in wind turbines has a direct impact on the dynamic performance of the machine and fluctuations in the power systems. Due to constant changes in wind ...
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The most common controller in wind turbine is the blade pitch angle control in order to get the desired power. Controlling the pitch angle in wind turbines has a direct impact on the dynamic performance of the machine and fluctuations in the power systems. Due to constant changes in wind speed, the wind turbines are of nonlinear and multivariate system. The design of a controller that can adapt itself with the system, at any given time, is of crucial importance. To limit the aerodynamic power gained from the wind turbine in the high wind speed areas, different methods has are applied on pitch angle. In this paper an extensive literature review on pitch angle control technique in wind turbine has been highlighted. Classical and adaptive controllers, structure control, robust control and intelligent control are among the control methods adopted in this study. In comparison of the controllers, although adaptive and robust controllers, with less sensitivity to changes in environmental conditions, outperform the classic controller, the intelligent controller system presents the best performance of the wind turbines through estimating the system variables and appropriate adaptation to changes at the operating point.
Hassan Ghasemi Mobtaker; Yahya Ajabshirchi; Seyed Faramarz Ranjbar; Mansour Matloobi; Morteza Taki
Abstract
Precise knowledge ofthe amount of global solar radiation plays an important role in designing solar energy systems. In this study, by using 22-year meteorologicaldata, 19 empirical models were tested for prediction of the monthly mean daily global solar radiation in Tabriz. In addition, various ...
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Precise knowledge ofthe amount of global solar radiation plays an important role in designing solar energy systems. In this study, by using 22-year meteorologicaldata, 19 empirical models were tested for prediction of the monthly mean daily global solar radiation in Tabriz. In addition, various Artificial Neural Network (ANN) models were designed for comparison with empirical models. For this purpose, the meteorological data recorded by Iran Meteorological Organization (1992–2013) was used. These data include: monthly mean daily sunshine duration, monthly mean ambient temperature, monthly mean maximum and minimum ambient temperature and monthly mean relative humidity.Theresults showed that the yearly average solar radiation in the region was 16.37 MJ m .Among the empirical models, the best result was acquired for model (19) with correlation coefficient (r) of 0.9663. Results also showed that the ANN model trained with total meteorological data in input layer (ANN5) produces better results in comparison to others. Root Mean Square Error (RMSE) and r for this model were1.0800 MJ m-2 and 0.9714, respectively. Comparison betweenthe model 19 and ANN5, demonstrated that modeling the monthly mean daily global solar radiationthrough the use of the ANNtechnique, yields better estimates. Mean Percentage Errors (MPE) for these models were 7.4754% and 1.0060%, respectively. -2 day-1
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.
Renewable Energy Resources and Technologies
Iman Ayoobi; Ramin Roshandel
Abstract
Light is a critical parameter for plant growth such that providing enough light for the plant can ensure better quality and higher yield in greenhouses. In many areas, in the cold seasons of the year, not enough natural light reaches the plant. Thus, to compensate for the natural light deficit, artificial ...
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Light is a critical parameter for plant growth such that providing enough light for the plant can ensure better quality and higher yield in greenhouses. In many areas, in the cold seasons of the year, not enough natural light reaches the plant. Thus, to compensate for the natural light deficit, artificial light is used. Since the use of artificial light leads to energy consumption, effective parameters in the energy consumption of the lighting system such as available natural light, greenhouse shape, and the on-off plan of the lighting system should be considered. In this paper, available natural light is estimated based on greenhouse structure in five cities of Iran. Then, the natural light deficit was investigated. Finally, to achieve clean cultivation, the utilization of photovoltaic panels is investigated to compensate for the electrical energy needed for supplementary lighting. The results show that although Iran is recognized as a region with high solar energy potential, natural light is not enough for optimum tomato lighting demand. Using supplementary lighting in greenhouses could compensate for the lack of natural light in proportion to the capacity of the lighting system. In 73.22 % to 91.32 % of days in the period of September to April, the natural light is not sufficient for optimum lighting. Therefore, 98 to 377 electricity is needed to supply power for supplementary lighting system. Accordingly, the photovoltaic area and its associated with costs to compensate electrical energy consumption for the supplementary lighting is estimated to be 0.47 to 2.58 per m2 of greenhouse area, which is equal to $ 171.08 to $ 939.12 per m2 of greenhouse area, respectively.
