Renewable Energy Resources and Technologies
Rasoul Aydram; Hossein Haji Agha Alizade; Majid Rasouli; Behdad Shadidi
Abstract
Reduced emissions of greenhouse gases and global warming can be made possible by discovering alternative energies and reduced dependence on fossil fuels. Biogas is considered as one of the alternatives to fossil fuels. This study investigates anaerobic co-digestion for the development of biogas with ...
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Reduced emissions of greenhouse gases and global warming can be made possible by discovering alternative energies and reduced dependence on fossil fuels. Biogas is considered as one of the alternatives to fossil fuels. This study investigates anaerobic co-digestion for the development of biogas with sheep blood and cheese whey. Digested cow manure was used as inoculum. Using the Design Expert 10 program and within the context of mixture design, the experiments were designed. Then, 22 experimental digesters with a volume of 500 mL were considered for doing the experiments considering the design output provided by the software. Each one was filled with 300 mL of different compositions of three matters. The digesters were kept in the mesophilic temperature range (37 °C ) for 21 days. Biogas was measured using the BMP test on a daily basis. According to the experimental findings, the best composition included 35 % sheep blood, 35 % cheese whey, and 30 % inoculum. This biogas composition produced a biogas yield of 146.66 mL/g vs. The amount of methane production in this compound was 73.33 mL/g vs. After modeling, the Design Expert software predicted an optimal composition including 44 % sheep blood, 24 % cheese whey, and 32 % inoculum. Biogas yield of this prediction was 143 mL/g vs. The findings show that in order to overcome acidification in digestion of matters such as cheese whey, a composition of matters with higher pH stability can be used to increase the amount of biogas and methane produced in a particular period. Furthermore, using inoculum accelerates the digestion operations due to existence of many microorganisms and saves time and energy.
Renewable Energy Resources and Technologies
Aychar Khajavipour; Mohammad Reza Shahraki; Faranak Hosseinzadeh Saljooghi
Abstract
The energy of processes is mainly supplied by fossil fuels. Short life of fossil energy sources and increasing environmental pollution caused by fossil fuels and increasing demand have made researchers introduce new solutions for supply of energy. Energy production in a photovoltaic solar power plant ...
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The energy of processes is mainly supplied by fossil fuels. Short life of fossil energy sources and increasing environmental pollution caused by fossil fuels and increasing demand have made researchers introduce new solutions for supply of energy. Energy production in a photovoltaic solar power plant is cost-effective due to being clean and renewable. The power generation of these plants is affected by their site due to climate conditions, effective radiation periods, and the rate of solar radiation absorption. Therefore, finding the optimal location to establish a solar power plant is important. Identifying effective location criteria and the importance of these criteria is effective in choosing the optimal location.In this research, in the first phase, the effective criteria in locating a photovoltaic solar power plant were investigated based on the Delphi method. Then, in the second phase, based on the criteria identified in the first phase, fuzzy hierarchy method was used to compare the criteria with each other and determine the importance of each of them. The results of the study showed that the rate of solar radiation and average temperature were the most important criteria in locating photovoltaic solar power plant. Moreover, the criteria of slope, distance to main roads, distance to power lines, and land use were of highest importance in locating a photovoltaic solar power plant.
Renewable Energy Resources and Technologies
Farid Jafarihaghighi; Hasanali Bahrami; Mehdi Ardjmand; Mehrdad Mirzajanzadeh
Abstract
The present study uses three generations of biodiesels and studies their effects on physical properties and exhaust gases. They are comprised of Palmaria palmate oil (third generation), Eucheuma spinosum oil (third generation), Eucheuma cottonii oil (third generation), Common wormwood oil (second generation), ...
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The present study uses three generations of biodiesels and studies their effects on physical properties and exhaust gases. They are comprised of Palmaria palmate oil (third generation), Eucheuma spinosum oil (third generation), Eucheuma cottonii oil (third generation), Common wormwood oil (second generation), Marjoram oil (second generation), Peganum harmala oil (second generation), Zingiber officinale oil (first generation), Anethum graveolens oil (first generation), and Cacao bean oil (first generation). Results show that first-generation oils gain a higher level of Calorific value around 41.16 MJ/kg than other generations. The longest carbon chain is observed by the first generation with higher unsaturated fatty acids than other generations (94.11 %). The first generation gains a higher level of density around 882 kg/m3 than other generations. Also, the first generation gains a higher level of flash point around 193 ˚C than other generations. The third generation gains a high level of cetane number at about 69, compared to other generations. The first generation gains a minimum level of cloud and pour point around -3 ˚C and -2 ˚C compared to other generations. Moreover, the third generation gains the lowest level of viscosity about 2.51 CSt compared to the first generation. The third generation gains the lowest level of NOx around 371 ppm compared to other generations. Finally, the third generation gains the lowest level of soot, CO, and HC around 0.47 Vol. %, 0.018 Vol. %, and 4.82 ppm, compared to other generations.
Renewable Energy Resources and Technologies
Abolfazl Taherzadeh Fini; Abolfazl Fattahi
Abstract
Energy crisis in the world motivates countries to hire new and renewable energies. One of the main and valuable renewable sources of energy is agricultural waste. This is widely disposed of through the world during the harvest, packing, and transportation. In many countries, agricultural waste is considerably ...
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Energy crisis in the world motivates countries to hire new and renewable energies. One of the main and valuable renewable sources of energy is agricultural waste. This is widely disposed of through the world during the harvest, packing, and transportation. In many countries, agricultural waste is considerably weighty. Nonetheless, most of that is used for animal feed or herbal fertilizer and no useful value is added. Despite its location in an arid region, Iran produces various citrus, cereals, and vegetables in high tonnage. The waste of the agricultural product, especially those disposed of by the food processing industries, such as fruit juice factories, remains also useless. The potential of the residues to extract biofuel is investigated in the current experimental study. Six samples of abundant agricultural products in Iran are chosen: sugarcane, grape, potato, orange peel, date, and mulberry. The processes of pretreatment, hydrolysis, and fermentation are performed and the extracted juice is directed to the distiller to gather bioethanol. To evaluate the distilled juice purity, a gas chromatography test is carried out. It is shown that date and mulberry can produce a maximum of 29.5 and 23 ml (ethanol)/100 g (dry waste) as the most efficient agricultural products.
Renewable Energy Resources and Technologies
Somayeh Naserpour; Hasan Zolfaghari; Parviz Zeaiean Firouzabadi
Abstract
One of the most important characteristics of site selection for solar energy system installations and optimum solar energy harvesting in the hilly or mountainous terrains is knowledge about the amount and duration of solar radiation within such topographic terrains. Solar radiation data are not readily ...
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One of the most important characteristics of site selection for solar energy system installations and optimum solar energy harvesting in the hilly or mountainous terrains is knowledge about the amount and duration of solar radiation within such topographic terrains. Solar radiation data are not readily available for most mountain terrains because of their rugged topography. For these areas, solar radiation data can be obtained through alternative methods such as the Hemispherical Viewshed Algorithm in which spatial and temporal variations of radiation are calculated in terms of elevation, slope, and terrain. In this study, this algorithm was used to estimate and model solar radiation in the Paraw Mountain in Kermanshah. The inputs for this method were ASTER Digital Elevation Model (DEM) with a spatial resolution of 30 m and meteorological parameters that affect solar radiation. The slope and aspect maps were created from ASTER DEM and layers for monthly direct, diffuse, global, and radiation periods were generated for the year 2016. The results showed that in the Paraw Mountain, the amount of solar radiation received was dependent on the slope orientation, as the north and northeast-facing slopes received the lowest and the south and southwest-facing slopes and the flat areas received the highest direct and global radiation (i.e., in terms of this factor, these landscapes can be recommended as the best site for solar energy system installations and optimum solar energy harvesting). The sum annual radiation period varies from 382.67 to 4310.9 hours, the total radiation received annually varies between 1005.56 and 7467.3 MJ/m2, and the sum monthly solar radiation is the highest in July (181.49-842.26 MJ/m2) and lowest in December (25.42-319.90 MJ/m2). Statistical error comparisons between station-based measurements and model-based estimates were performed via R2, measures. As a result, this model was recommended for solar radiation estimation with acceptable accuracy, especially in high areas with rugged topography where solar radiation data are not readily available.
Renewable Energy Resources and Technologies
Sajad Saberi; Behrooz Rezaie
Abstract
This paper presents a sensorless speed control algorithm based on Finite Control Set Model Predictive Control (FCS-MPC) for Permanent Magnet Synchronous Motor (PMSM) fed by a 3-level Neutral-Point Clamped (NPC) converter. The proposed scheme uses an anti-windup Proportional-Integral (PI) controller concept ...
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This paper presents a sensorless speed control algorithm based on Finite Control Set Model Predictive Control (FCS-MPC) for Permanent Magnet Synchronous Motor (PMSM) fed by a 3-level Neutral-Point Clamped (NPC) converter. The proposed scheme uses an anti-windup Proportional-Integral (PI) controller concept to generate the reference electromagnetic torque using the error of speed. Then, FCS-MPC uses this torque reference and other parameters such as a current limitation, neutral point voltage unbalance, and switching frequency to control the converter gate signals. Also, an Adaptive Nonsingular Fast Terminal Sliding Mode Observer (ANFTSMO) was employed to estimate rotor position precisely in positive (clockwise) and negative (counterclockwise) speed to eliminate the encoder. The proposed algorithm has fast dynamics and low steady-state error. Moreover, torque fluctuation and current distortion reduced compared with Space Vector Pulse Width Modulation (SVPWM) based speed control and Direct Predictive Speed Control (DPSC). Simulation results using MATLAB/SIMULINKÒ demonstrate the performance of the proposed scheme.
Renewable Energy Resources and Technologies
Selfa Johnson Zwalnan; Nanchen Nimyel Caleb; Mahan Morgan Mangai; Nantim Yohana Sanda
Abstract
The effect of solar collector configurations on the thermal efficiency of an active solar water heater was investigated using TRNSYS in this study. Two versions of a solar heater were formulated on the basis of serpentine and riser-header flat plate configurations. Both models were simulated based on ...
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The effect of solar collector configurations on the thermal efficiency of an active solar water heater was investigated using TRNSYS in this study. Two versions of a solar heater were formulated on the basis of serpentine and riser-header flat plate configurations. Both models were simulated based on the same parameters and weather conditions. Besides, in accordance with clear sky and cloudy sky conditions, a parametric analysis was performed to determine the impact of varying parameters on the thermal efficiency of the two models. The results showed that the serpentine-based device model provided about 2.62 % more usable thermal energy than the riser-header configuration. In addition, both models demonstrated the same response and sensitivity to changes in the collector area and the volume of the tank. However, on a cloudy day, the efficiency of serpentine showed a significant improvement and sensitivity to flow variance with an efficiency gap of about 30 % to the riser header configuration.
Renewable Energy Resources and Technologies
Mohammad Reza Shekari; Seyed Mohammad Sadeghzadeh; Mahdi Golriz
Abstract
In recent decade, Perovskite Solar Cells (PSCs) have received considerable attention compared to other photovoltaic technologies. Despite the improvement of Power Conversion Efficiency (PCE) of PSCs, the chemical instability problem is still a matter of challenge. In this study, we have fabricated two ...
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In recent decade, Perovskite Solar Cells (PSCs) have received considerable attention compared to other photovoltaic technologies. Despite the improvement of Power Conversion Efficiency (PCE) of PSCs, the chemical instability problem is still a matter of challenge. In this study, we have fabricated two kinds of PSCs based on gold and carbon electrodes with the optimal PCE of about 15 % and 10.2 %, respectively. We prepared a novel carbon electrode using carbon black nanopowder and natural graphite flaky powder for Hole Transport Material (HTM) free carbon-based PSC (C-PSC). Current density-voltage characteristics over time were measured to compare the stability of devices. Scanning Electron Microscope (SEM) and Energy-dispersive X-ray Spectroscopy (EDS) analyses were carried out to study applied materials, layer, and surface structures of the cells. The crystal structure of perovskite and its association with the stability of PSCs were analyzed using an obtained X-ray diffraction (XRD) pattern. As a result, the constructed HTM-free C-PSC demonstrated high stability against air, retaining up to 90 % of its optimal efficiency after 2000 h in the dark under ambient conditions (relative humidity of (50 ± 5); average room temperature of 25 °C) in comparison to constructed gold-based PSCs (Gold-PSC) which are not stable at times. The experimental results show that novel low-cost and low-temperature carbon electrode could represent a wider prospect of reaching better stability for PSCs in the future.
Renewable Energy Resources and Technologies
Seyed Ali Akbar Fallahzadeh; Navid Reza Abjadi; Abbas Kargar; Frede Blaabjerg
Abstract
This study investigates a new double-stage single-phase Grid-Connected (GC) Photo-Voltaic (PV) system. This PV system includes a DC-DC Positive Output Super Lift Luo Converter (POSLLC) and a single-phase inverter connected to a grid through an RL filter. Due to its advantages, the POSLLC was used between ...
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This study investigates a new double-stage single-phase Grid-Connected (GC) Photo-Voltaic (PV) system. This PV system includes a DC-DC Positive Output Super Lift Luo Converter (POSLLC) and a single-phase inverter connected to a grid through an RL filter. Due to its advantages, the POSLLC was used between PV panel and inverter instead of the conventional boost converter. The state space equations of the system were solved. By using two Sliding Mode Controls (SMCs), PV panel voltage and POSLLC inductor current were controlled and the designed controls were compared. Two of these SMCs included a simple Sign Function Control (SFC) and a conventional SMC. To control the power injected into the grid with a unity power factor, an SMC was used. Perturb and Observe (P&O) method was employed to reach maximum power of the PV panel. The Maximum Power Point Tracking (MPPT) control generated the voltage reference of the PV panel. Similar controls were used for the boost converter instead of POSLLC. The obtained results were compared.
Renewable Energy Resources and Technologies
Ramasamy Dhivagar; Murugesan Mohanraj
Abstract
In this experimental work, the energy efficiency and performance parameters of a coarse aggregate-assisted single-slope solar still were analyzed using Taguchi analysis. The preheated inlet saline water was sent to the solar still using thermal energy accumulated in coarse aggregate to enhance its productivity ...
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In this experimental work, the energy efficiency and performance parameters of a coarse aggregate-assisted single-slope solar still were analyzed using Taguchi analysis. The preheated inlet saline water was sent to the solar still using thermal energy accumulated in coarse aggregate to enhance its productivity and energy efficiency. The daily distillate of the proposed model was observed to be about 4.21 kg/m2 with the improved efficiency of around 32 %. Furthermore, the parameters that influenced the performance of the solar stills and their levels were identified using Taguchi analysis. The Signal to Noise (S/N) ratios of the coarse aggregate temperature, saline water temperature, glass temperature and energy efficiency were observed to be about 45.4 °C, 41.4 °C, 36.7 °C and 20.07 %, respectively. The results revealed that, the percentage difference between predicted and experimental values was observed to be about 1.6 %, 0.6 %, 1.5 % and 3.3 %, respectively. The optimization method confirmed that there was good agreement between the predicted and experimental values.
Renewable Energy Resources and Technologies
Aryan Tabrizi; Mehdi Rahmani
Abstract
Reliability is an essential factor in Photovoltaic (PV) systems. Solar power has become one of the most popular renewable power resources in recent years. Solar power has drawn attention because it is free and almost available worldwide. Moreover, the price of maintenance is lower than other power resources. ...
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Reliability is an essential factor in Photovoltaic (PV) systems. Solar power has become one of the most popular renewable power resources in recent years. Solar power has drawn attention because it is free and almost available worldwide. Moreover, the price of maintenance is lower than other power resources. Since there are no moving parts in PV systems, their reliability is relatively high. It is assumed that a typical PV system can operate 20–25 years with minimum possible interruptions. However, solar power systems may fail, the same as any other systems. It is indicated by several studies that the PV inverters are responsible for major failures in PV systems, as other components are almost passive. Hence, the reliability of the inverter has maximum impact on the reliability of the whole PV system. Thus, not only assessing and calculating the reliability value of inverter is highly crucial, but also increasing its value is essential, as well. This paper calculates and evaluates the reliability of PV single-stage inverters exclusively. Furthermore, there are suggestions that improve their reliability value.
Renewable Energy Resources and Technologies
Muhamad Mustafa Mundu; Stephen Ndubuisi Nnamchi; Onyinyechi Adanma Nnamchi
Abstract
The present study is concerned with the development, estimation and validation of sunshine hours models (SHM) in Uganda. The SHM is based on geographical (latitude) and climatological (clearness index) indices. The meteosat data (1984-2018) acquired from the National Aeronautics and Space Administration ...
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The present study is concerned with the development, estimation and validation of sunshine hours models (SHM) in Uganda. The SHM is based on geographical (latitude) and climatological (clearness index) indices. The meteosat data (1984-2018) acquired from the National Aeronautics and Space Administration were used to compute the coefficients of the models which, yielded a coefficient of determination close to unity, signifying a good association between the sunshine hours (SH) and the associated indices. The models become distributed by introducing a longitudinal function of clearness index into the primary SHM developed. Moreover, the models were subjected to statistical validation using; mean absolute relative error (MARE), root mean square error (RMSE) and mean absolute percentage difference (APD). Consequently, the primary SHM showed strong agreement with the measured SH data in the three regions with the exception of the northern region with flawed on-station data. Also, validation of the models by; {MARE, RMSE, APD} for Eastern, Central and Western regions, yielding the following results; {0.0788,0.5441,7.8778},{0.0390,0.1453,3.9013} and {0.0124,0.0528,1.2436}, respectively. The following maximum SH; 11.16, 7.87, 9.52, 8.86 and 6.06 h were recorded for Non-regional, Northern, Eastern, Central and Western regions, respectively. Further, comparative validation with redeveloped global SHM showed that the present model stands in all the regions, whereas the global models validated only in the Eastern region. This is attributed to the synergy of geographical and climatological indices against the global models only based on climatological index. The model results show the order of regional SH distribution; eastern>northern>central>western region. These results could be employed in solar power, exploitation and agrometeorology development. This study further recommends for adoption of the present model to non-equatorial regions upon redevelopment as a meaningful extension of this work.
Renewable Energy Resources and Technologies
Ahmad Naderi Nobandegani; Mohammad Ahmadzadehtalatapeh
Abstract
In the present study, the performance of a Desiccant Evaporative Cooling System (DECS) under eight different designs to provide the desired indoor air conditions for administration buildings was explored via TRNSYS software. An administration building in Chabahar, Iran as a region with a high cooling ...
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In the present study, the performance of a Desiccant Evaporative Cooling System (DECS) under eight different designs to provide the desired indoor air conditions for administration buildings was explored via TRNSYS software. An administration building in Chabahar, Iran as a region with a high cooling load demand was considered for the study. The simulation results indicated that the two-stage desiccant cooling system (Des. H) was the most suitable design, and it enjoyed the potential to keep the indoor air conditions within the standard recommendations. It was also shown that Des. H is the superior design in terms of energy performance and can meet the space cooling load requirements. The study showed that Des. H had the highest COP value with 2.83. The possible application of solar energy to the regeneration process of the Des. H was also studied. The simulations revealed that Des. H with and without the solar panels had less energy consumption than the existing system. The study showed that the application of Des. H could ensure 26.97 % saving in power per year in comparison to the existing system. Moreover, it was demonstrated that the addition of PVT panels to Des. H could increase the rate of annual power saving to about 68.03 %.
Renewable Energy Resources and Technologies
Hossein Dastres; Ali Mohammadi; Behrooz Rezaie
Abstract
This paper deals with the problem of maximizing the extracted power from a wind turbine in the presence of model uncertainties and input saturation. An adaptive second-order integral terminal sliding mode speed control method is utilized to address this problem. The presented method benefits from the ...
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This paper deals with the problem of maximizing the extracted power from a wind turbine in the presence of model uncertainties and input saturation. An adaptive second-order integral terminal sliding mode speed control method is utilized to address this problem. The presented method benefits from the advantages of several control techniques, i.e., adaptability, robustness, finite-time convergence, and the capability of coping with the input saturation. The robust nature of the designed controller causes its high performance in facing the uncertainties in the wind turbine model. In this paper, to compensate for the effect of input saturation, an auxiliary dynamic variable is added to the tracking error and also an adaptation law is designed so that the finite-time convergence of the closed-loop system can be achieved. Moreover, to reduce the mechanical stresses which are the result of the chattering phenomenon, a second-order sliding surface is employed. The finite-time convergence of the designed controller has been proven by the Lyapunov stability theorem in which the finite-time convergence of the tracking error to zero is guaranteed. Finally, to illustrate the effectiveness and satisfactory performance of the proposed controller, two comparative simulations are carried out. The results of this comparison show that the proposed controller has less error to track the optimal speed and when the model uncertainties and input saturation occur in the wind turbine system, the proposed controller is almost 3 % more efficient than the existing controllers.
Renewable Energy Resources and Technologies
Parvez Mosharraf; Md. Saroyar Zahan; Dilip Kumar Das; Suman Chowdhury
Abstract
This study offers an effective solution to meet the growing demands of biogas plants for energy. This paper presents a model and simulates the digestion process of biogas production from the organic and food processing waste that contains high moisture. Biogas is produced by bacteria through the bio-degradation ...
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This study offers an effective solution to meet the growing demands of biogas plants for energy. This paper presents a model and simulates the digestion process of biogas production from the organic and food processing waste that contains high moisture. Biogas is produced by bacteria through the bio-degradation of organic material under anaerobic conditions. According to the findings, in case of biogas production, the broiler chicken manure is approximately 88 %. From the analysis, it is observed that the chicken broiler waste is approximately 88 % more efficient than the unsorted waste. In addition, in the case of digestate, the cow manure is approximately 6.25 % more efficient than the garden waste. The present study aims to investigate the performance of different types of wastes regarding biogas production. To this end, different types of waste were considered in data analysis. According to the data analysis, biogas production is highly affected by the type of waste.
Renewable Energy Resources and Technologies
Mahdi Shahmari; Payam Zarafshan; Shahriar Kouravand; Morteza Khashehchi
Abstract
Renewable energies as a clean replacement resource of fossil fuels have many advantages, among which wind has the potential to be the very applicable source in the world. To use wind energy, two kinds of turbines have been developed; the Vertical Axis Wind Turbine (VAWT) and Horizontal Axis Wind Turbine ...
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Renewable energies as a clean replacement resource of fossil fuels have many advantages, among which wind has the potential to be the very applicable source in the world. To use wind energy, two kinds of turbines have been developed; the Vertical Axis Wind Turbine (VAWT) and Horizontal Axis Wind Turbine (HAWT). In small scale applications, using a VAWT has some advantages such as low cost and noise, simple mechanism, and the low sensitivity to the wind direction. In this paper, the design and analysis of a combined wind turbine, consist of the Savonius-Darrieus rotor, are performed to use in irrigation applications. To predict the output power, a series of experiments were conducted using the Computational Fluid Dynamics (CFD) method. For this purpose, ANSYS fluent and Q-Blade software programs are used. To design the rotor performance, NACA symmetric airfoils are considered. Next, this combined turbine was made and experimental tests were performed. Finally, the output power is computed and so, the water flow rate for irrigation purposes such as water pumping is obtained. The results indicate that the self-starting of the turbine is improved using the considered design. This could be useful in regions with low wind speed.
Renewable Energy Resources and Technologies
Mehdi Zare; Barat Ghobadian; Seyed Reza Hassan-Beygi; Gholamhasan Najafi
Abstract
In CI engines, the evaporation rate of fuel on various hot surfaces, including the combustion chamber, has a significant effect on deposit formation and accumulation, the exhaust emissions of PM and NOx, and their efficiency. Therefore, the evaporation of liquid fuel droplets impinging on hot surfaces ...
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In CI engines, the evaporation rate of fuel on various hot surfaces, including the combustion chamber, has a significant effect on deposit formation and accumulation, the exhaust emissions of PM and NOx, and their efficiency. Therefore, the evaporation of liquid fuel droplets impinging on hot surfaces has become an important subject of interest to engine designers, manufacturers, and researchers. The aim of this study is to investigate the evaporation characteristics based on droplet lifetime and critical surface temperature (the maximum heat transfer rate) of diesel and biodiesel fuel droplets on hot surfaces. In order to determine the effects of diesel fuel, canola oil biodiesel, and castor oil biodiesel, the droplets impinging on the hot surfaces of aluminum alloy (7075) and steel alloy (1.5920) and the evaporation lifetime of diesel and biodiesel fuels were measured. Statistical analysis (ANOVA and Duncan’s multiple-range test) was carried out using SAS software. The results showed the maximum critical surface temperature of 450 °C for the castor oil biodiesel on steel 1.5920 surface and the minimum one for diesel fuel (350 °C). In this case, both surfaces had the same droplet lifetimes of approximately 2 s. The results of ANOVA showed the significant effect of the surface material and fuel type on the evaporation lifetime of fuel droplet at 1 % probability.
Renewable Energy Resources and Technologies
Saeed Hosseinpour; Seyed Alireza Haji Seyed Mirza Hosseini; Ramin Mehdipour; Amir Hooman Hemmasi; Hassan Ali Ozgoli
Abstract
In this study, an advanced combined power generation cycle was evaluated to obtain sustainable energy with high power and efficiency. This combined cycle includes biomass gasification, the Cascaded Humidified Advanced Turbine (CHAT), and the steam turbine. The fuel consumed by the system is derived from ...
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In this study, an advanced combined power generation cycle was evaluated to obtain sustainable energy with high power and efficiency. This combined cycle includes biomass gasification, the Cascaded Humidified Advanced Turbine (CHAT), and the steam turbine. The fuel consumed by the system is derived from the gas produced in the biomass gasification process. The biomass consumed in this study is wood because of its reasonable supply and availability. The economic analysis conducted in the present research has produced significant gains. The proposed cycle with current prices intended to sell electricity in Iran has a positive Net Present Value (NPV). Therefore, the presented cycle in terms of energy supply has good economic value. Due to the significantly higher purchase/sale price of electricity from renewable power plants in developed countries in Europe or the United States, the power generation cycle proposed in this study may be more economically feasible in other regions than Iran. Of course, with a slight price increase in electricity sales in Iran (3 US₵ kWh-1), the proposed system will have acceptable NPV. Because of the complicated equipment used in high-pressure and low-pressure turbines and compressors sets, the equipment used in this cycle requires a higher initial investment cost than conventional power generation systems. The results showed that the investment cost per unit of energy was approximately 909 USD kW-1.
Renewable Energy Resources and Technologies
Arash Abedi; Behrooz Rezaie; Alireza Khosravi; Majid Shahabi
Abstract
This paper presents a novel local control method for the converter-based renewable energy resources in a stand-alone DC micro-grid based on energy analysis. The studied DC micro-grid comprises the renewable energy resources, back-up generation unit, and battery-based energy storage system, which are ...
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This paper presents a novel local control method for the converter-based renewable energy resources in a stand-alone DC micro-grid based on energy analysis. The studied DC micro-grid comprises the renewable energy resources, back-up generation unit, and battery-based energy storage system, which are connected to the common DC-bus through the buck and bidirectional buck-boost converters. The proposed control method satisfies the stability of the micro-grid output variables, along with current control and voltage regulation by controlling the switching functions of the converters, regardless of the energy resource dynamics. The dynamic component of the switching function is extracted as a control signal using the state-feedback through a mathematical method. The control inputs are designed based on Lyapunov stability theorem to guarantee the stability of output variables (DC-bus voltage and generated currents) in a stand-alone DC micro-grid through an energy analysis. The proposed distributed controller can be easily generalized as a platform with all kinds of the stand-alone DC micro-grids comprising any type or number of distributed generations such as renewable energy resources, fossil-fuel-based generations, and energy storage units. Other features of this local control method are simplicity, celerity, comprehensiveness, and independence of the distributed generations. The dynamic performance assessment of the proposed controller is verified through a simulation in MATLAB/SIMULINKÒ environment. The results validate the accuracy and stability of the proposed control strategy in various operating conditions.
Renewable Energy Resources and Technologies
Amir Reza Khedmati; Mohammad Behshad Shafii
Abstract
The humidification-dehumidification system is one of the desalination technologies that can utilize non-fossil thermal sources and requires insignificant input energy. This system is usually suitable for rural areas and places far from the main sources of energy. The purpose of this study is to obtain ...
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The humidification-dehumidification system is one of the desalination technologies that can utilize non-fossil thermal sources and requires insignificant input energy. This system is usually suitable for rural areas and places far from the main sources of energy. The purpose of this study is to obtain the most suitable working conditions and dimensions of this system. In this research, thermodynamic modeling was first performed for a simple type of the system (water-heated); then, the effect of parameters on the system performance was investigated. Modeling was conducted through a numerical simulation; furthermore, the assumption of the saturation of exhaust air from the humidifier was also considered in the mentioned code. Afterward, a comparison was made between two different forms of the system, and the proper form was chosen for the rest of the research. Moreover, through heat transfer equations, the dimensions of the two main parts of the system, i.e., humidifier and dehumidifier, were calculated. Besides, multi-objective optimization was carried out for two objective functions, i.e., gained output ratio (GOR) and the system volume, to reduce the space occupied by the system and reach the desired efficiency simultaneously. The optimization was performed using a simulation program, and results were obtained for different weights in order to optimize each objective function. For instance, 379 liters of freshwater can be produced in a day with a total volume of 48 liters for the humidifier and the dehumidifier in the optimized system.
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
Alireza Shirneshan; Mohammad Mostofi
Abstract
The determination of the optimum engine working conditions plays an important role in increasing engine performance and reducing exhaust emissions. The main objective of this study is to optimize the performance and emission characteristics of a CI engine fueled with aviation fuel-biodiesel-diesel blends ...
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The determination of the optimum engine working conditions plays an important role in increasing engine performance and reducing exhaust emissions. The main objective of this study is to optimize the performance and emission characteristics of a CI engine fueled with aviation fuel-biodiesel-diesel blends at various engine speeds and loads using Mixture-RSM. According to the experimental tests carried on a 4-cylinder engine, the mathematical models were developed. Then, the optimization processes were defined as the six scenarios containing the consideration of performance or emission parameters or both of them. Scenario 1 shows that the higher percentage of diesel and jet fuel can improve the performance parameters of the engine; however, Scenario 2 shows that only higher percentage of diesel can improve the engine emission due to negative effect of biodiesel on the NOx emissions and negative impact of aviation fuel on the CO and HC emissions that limit the amount of biodiesel and aviation fuel in the fuel mixture. The results also show that Scenario 3 does not vary compared to Scenario 2. The optimized point for both of engine performance and emission parameters presented in Scenario 6 was calculated as D48.9B32.7J18.4 at 2526 RPM and full engine load to obtain 88.4 (kW), 337 (N.m), 255 (gr/Kw.hr), 0.0268 (%), 469 (ppm), 7.7 (%) brake power, torque, BSFC, CO, NOx, and HC emission, respectively.
Renewable Energy Resources and Technologies
Tahmineh Taheri Dezfouli; Reza Marandi; Morteza Kashefiolasl; Mozhgan Emtyazjoo; Maasomeh Javaheri
Abstract
The modern BioElectrochemical technologies can convert the energy stored in the chemical bonds of biodegradable organic materials to renewable electrical energy through the catalytic reactions of microorganisms while treating the waste waters. The present research was conducted to evaluate the efficiency ...
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The modern BioElectrochemical technologies can convert the energy stored in the chemical bonds of biodegradable organic materials to renewable electrical energy through the catalytic reactions of microorganisms while treating the waste waters. The present research was conducted to evaluate the efficiency of a single-chamber Bioelectrochemical system with the carbon aerogel catalyst, as a simple and inexpensive method, in removing the corrosive and odorous sulfur compounds from municipal wastewater simultaneously with electricity generation by using indigenous bacterial consortium. The used bacteria were isolated from local lagoon sediments, and the municipal wastewater was used as the substrate. During six months of the Bioelectrochemical cell operation, the sulfate concentration was dropped to a minimum of 63 ± 57.2 mg/l, indicating the ability of the system to remove 71.8 % of the sulfate from the municipal wastewater and the production of bioenergy. With a 304 mV Open Circulate voltage, the maximum removal of Chemical Oxygen Demand was 80 % and the maximum power density was 1.82 mW/m2. Carbon aerogel, as a novel material with suitable absorbance and resistance to oxidation at urban wastewater pH, can be, therefore, coated on electrodes to facilitate the Oxidation Reduction Reactions and electricity transmission. The existence of elemental sulfur in the sediments showed that these systems could be optimized to recover the elemental sulfur from the municipal wastewater.
Renewable Energy Resources and Technologies
Amir Goshadrou
Abstract
Glycyrrhiza glabra residue (GGR) was efficiently subjected to concentrated phosphoric acid (PA) pretreatment with/without surfactant assistance, and promising results were obtained following separate enzymatic hydrolysis and fermentation (SHF) of the biomass. Pretreatment was carried out using 85 % PA ...
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Glycyrrhiza glabra residue (GGR) was efficiently subjected to concentrated phosphoric acid (PA) pretreatment with/without surfactant assistance, and promising results were obtained following separate enzymatic hydrolysis and fermentation (SHF) of the biomass. Pretreatment was carried out using 85 % PA either at 50 or 85 °C with 12.5 % solid loading for 30 min. In parallel experiments, the intact GGR was impregnated in 2 % (w/w) surfactant (Polyethylene glycol) aqueous solution prior to the PA pretreatment. Consequently, the pretreated materials were subjected to enzymatic hydrolysis (50 °C, 72 h) using 25 FPU/g cellulase, and the most digestible biomass was nominated for conversion to bioethanol. Substantial improvement in digestibility of GGR (~92 % hydrolysis yield) was observed following surfactant-assisted PA pretreatment, whereas digestibility yield from the untreated biomass was only 16.1 %. Consequently, the ethanol production form GGR was significantly enhanced by 19.7-fold through separate hydrolysis and fermentation of biomass. Different analytical approaches including water retention value, Simons’ staining, and crystallinity together with FESEM imaging revealed that the improved surface hydrophilicity, increased substrate accessibility to enzyme, and decreased crystallinity could be the major effects of PA pretreatment, leading to higher susceptibility of GGR to enzymatic hydrolysis and subsequent ethanol production.
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.
