Hitesh N. Panchal; P. K. Shah
Abstract
A solar still is a viable option when the demand of potable water does not exceed more than 3 litres. Enhancement in distillate output from the solar still is a main goal of many researchers all over the world. In this research, the effect of copper and aluminium plates on distillate output is investigated ...
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A solar still is a viable option when the demand of potable water does not exceed more than 3 litres. Enhancement in distillate output from the solar still is a main goal of many researchers all over the world. In this research, the effect of copper and aluminium plates on distillate output is investigated experimentally as well as theoretically at different water depths under the same climate conditions. In solar stills, first we used solar still augmented with copper plates, second with aluminium and third without any plate called passive solar still. An energy balance equation was applied to solar still for calculation of theoretical distillate output of a solar still with different plates. Three experiments still of 1 m2 in area were constructed from locally available materials. In this work, it was found that the experimental and theoretical results are in good agreement. It was also found that using copper plate in a solar still increases distillate output by 20% (at water depth of 3 cm) and 32% (at water depth of 6 cm) compared with passive solar still, and using an aluminium plate increases distillate output by 10% (at water depth of 3 cm) and 20% (at water depth of 6 cm).
Maryam Nosratinia; Ali Asghar Tofigh; Mehrdad Adl
Abstract
The use of renewable energy sources is often suggested to be a good solution for climate change and the dependency to fossil fuel. Biogas utilization is a one of these promising options that can mitigate these problems since biogas is produced by the fermentation of waste, so is rich in methane and has ...
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The use of renewable energy sources is often suggested to be a good solution for climate change and the dependency to fossil fuel. Biogas utilization is a one of these promising options that can mitigate these problems since biogas is produced by the fermentation of waste, so is rich in methane and has the same characteristics as natural gas. Biogas has increasingly been noticed in different countries during last decades, but Iran could not reach its deserved position in comparison with others. The authors believe that absence of a proper management and information system is the main reason for this problem. In this article a decision system is designed in order to reduce the involved risks in making decision and helping in selecting the most appropriate commercialization strategies for utilization of biogas which is achievable from Iran’s livestock and poultry wastes. After a short hint to biogas and its techniques, in this article the main related criteria including biogas site selection and production techniques and utilization options in Iran have been chosen and their weights were calculated according to analytical hierarchy process (AHP). The weight obtained in this research should be considered in future development of Biogas by considering local specifications.
Sajjad Golshannavaz; Daryoush Nazarpour
Abstract
Encountering series-compensated transmission lines, sub-synchronous resonance (SSR) may strike the power system by jeopardizing its stability and mechanical facilities. This paper aims to verify the capability of static synchronous series compensator (SSSC) in mitigating the mechanical and electrical ...
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Encountering series-compensated transmission lines, sub-synchronous resonance (SSR) may strike the power system by jeopardizing its stability and mechanical facilities. This paper aims to verify the capability of static synchronous series compensator (SSSC) in mitigating the mechanical and electrical oscillations such as SSR in wind farm integrations. A wind turbine with a self–excited induction generator (SEIG) represents the wind farm and it is connected to the system through a transmission line compensated by a series capacitor. Both the induction–generator (IG) effect and torsional interaction (TI) on SSR occurrence are examined. Simulations are carried out using EMTDC/ PSCAD on the IEEE first SSR benchmark model along with a SEIG based wind turbine. Also a Fast Fourier Transform (FFT) analysis is performed to determine the dominant torsional mode existing in the turbine generator system. The SSSC impact on SSR mitigation is interrogated in various case studies. A SSSC with a simple power flow control in its base case is first considered. It is shown that the SSSC can damp the SSR even without any specific auxiliary controller. In the following the same SSSC is shown to effectively damp SSR when equipped with an auxiliary SSR damping (SSRD) controller.
Hamid Reza Chitsaz; Mohammadreza Omidkhah; Kambiz Tahvildari
Abstract
Energy obtained from renewable sources has increased its participation in the energy matrix worldwide, and it is expected to maintain this tendency. Both in large and small scales, there have been numerous developments and research with the aim of generating fuels and energy using different raw materials ...
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Energy obtained from renewable sources has increased its participation in the energy matrix worldwide, and it is expected to maintain this tendency. Both in large and small scales, there have been numerous developments and research with the aim of generating fuels and energy using different raw materials such as alternative crops, algae and waste cooking oil. Capparis spinosa seed (containing 32% triglycerides) is used as an excellent source for biodiesel production. In this work, biodiesel (Fatty acid methyl ester) is produced by trans-esterification of Capparis spinosa oil, in the presence of methanol and sodium hydroxide as an alkaline catalyst. According to data collection, pilot of biodiesel production is simulated by using HYSYS v3.2 software. The yield of biodiesel in the presence of sodium hydroxide was considered 94%. The results of FTIR and GC-MS spectra showed trans-esterification reaction has been complete. According to the results, the produced biodiesel is in the range of ASTM Standard.
Ayda Montaser Koohsari; Rima Fayaz; Behrouz Mohammad Kari
Abstract
As part of sustainable architecture principles and practices, designers need to define building's architectural requirements based on climatic conditions, environmental preservation and reduction in energy consumption. The natural energy sources such as solar radiation affect thermal and lighting performances ...
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As part of sustainable architecture principles and practices, designers need to define building's architectural requirements based on climatic conditions, environmental preservation and reduction in energy consumption. The natural energy sources such as solar radiation affect thermal and lighting performances of buildings depending on its facade characteristics. Traditionally, buildings thermal and lighting analyses are employed independently. As non-linear relationships are often disclosed, an integrated thermal and lighting approach is necessary to optimize the façade configuration. This paper presents an integrated model of thermal and lighting energy simulation which investigates 1650 window configurations, and sunshade size in a residential building in a mild climate to find the optimum solution. The integrated thermal and daylight simulations are carried out using Energy PlusV8-1-0, Daysim 1.08 and Radiance 2.01 software. Calculations are performed on hourly basis for an entire year. First, climatic parameters are validated by on-site measurement. Then all thermal and lighting parameters of the simulated model are defined. Next, the optimal results of the window and sunshade characteristics in four main dimensions (South, North, East, and West) are presented by genetic algorithm approach. The results show that, the window orientation affects up to 10% on energy saving, and horizontal windows with higher sill levels are more energy-efficient in south and east orientations. The optimal sunshade angel of the south orientation is 65-85 degree and its optimal range of Window Wall Ratio(WWR) is 15-25%.
Hamid Ghaderi; Mona Asadi; Saeed Shavalpour
Abstract
Switchgrass is known as one of the best second-generation lignocellulosic biomasses for bioethanol production. Designing efficient switchgrass-based bioethanol supply chain (SBSC) is an essential requirement for commercializing the bioethanol production from switchgrass. This paper presents a mixed integer ...
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Switchgrass is known as one of the best second-generation lignocellulosic biomasses for bioethanol production. Designing efficient switchgrass-based bioethanol supply chain (SBSC) is an essential requirement for commercializing the bioethanol production from switchgrass. This paper presents a mixed integer linear programming (MILP) model to design SBSC in which bioethanol demand is under auto-regressive moving average (ARMA) time series models. In this paper, how a SBSC design is affected by ARMA time series structure of bioethanol demand is studied. A case study based on North Dakota state in the United States demonstrates application of the proposed approach in designing the optimal SBSC. Moreover, SBSC optimal design is forecasted for the time horizon of 2013 to 2020 with the bioethanol demand acquired from the ARMA models to provide insights for designing and minimizing total cost of SBSC in the future efficiently. Finally, in order to validate the proposed approach, a reproduction behavior test is done. Also, a comparative analysis based on a SBSCND model from the recent literature is elaborated to show the performance of the proposed approach.
Mohammad Kord; Seyed Mojtaba Sadrameli; Barat Ghobadian
Abstract
The purpose of this research work was to investigate the optimum operating conditions for biodiesel production from castor oil using a microwave. The Box–Behnken design of experiment was carried out using the Design Expert 7. A response surface methodology (RSM) was used to analyze the influence ...
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The purpose of this research work was to investigate the optimum operating conditions for biodiesel production from castor oil using a microwave. The Box–Behnken design of experiment was carried out using the Design Expert 7. A response surface methodology (RSM) was used to analyze the influence of the process variables (molar ratio of methanol to castor oil, catalyst concentration, reaction time, and microwave power) on the biodiesel yield. Optimizing biodiesel production reaction based on the yield of reaction by means of response surface method showed that 1.44 wt.% of catalyst concentration, 7.12:1 molar ratio of alcohol to oil, microwave power of 500 W and 120 seconds of reaction time produces the best results for maximizing the conversion percent. Finally, Biodiesel samples were analyzed with Gas Chromatography (GC) method for determination of fatty acid methyl ester yield. The yield of reaction obtained was 92.15% with above operating conditions and temperature of output flow was 58 oC.
Abbas Rajabi Khanghahi; Mohammad Zamen; Mehdi Soufari; Majid Amidpour; Ali Abbas Nejad
Abstract
One of the subjects in solar water heater design is considering distribution of hot water consumption during the day. For example, each of the household, commercial, office, school, and industrial consumptions have a particular distribution of hot water consumption named pattern in this article. In solar ...
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One of the subjects in solar water heater design is considering distribution of hot water consumption during the day. For example, each of the household, commercial, office, school, and industrial consumptions have a particular distribution of hot water consumption named pattern in this article. In solar computation principles, the effect of longitude, latitude, and altitude on collector angle has been clearly presented. However, the effect of consumption pattern especially on the collector orientation has been rarely investigated. The aim of the current study is to survey the effect of various consumption patterns on the collector’s orientation and tilt angle and so calculation of related energy saving. So, five common patterns including office building, commercial building, afternoon and morning shift high school and a 15-unit apartment have been studied and optimal surface azimuth angle and tilt angle determined. It has been observed that 11 to 14 % energy saving can be archived by selecting the optimal angles with respect to hot water consumption pattern in comparison to a state that collectors are orientated for maximum reception of solar energy. Also effect of solar fraction, storage volume and amount of hot water consumption are studied and discussed.
Mahdi Hashemzadeh Gargari; Seyed Mojtaba Sadrameli; mohammad taherkhani
Abstract
Both the continuous and batch transesterification of linseed oil were examined in order to maximize the fatty acid methyl esters (FAME) yield. The continuous process was conducted in a packed bed reactor using calcium oxide as a heterogeneous catalyst. In addition, the impact of two variables, namely ...
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Both the continuous and batch transesterification of linseed oil were examined in order to maximize the fatty acid methyl esters (FAME) yield. The continuous process was conducted in a packed bed reactor using calcium oxide as a heterogeneous catalyst. In addition, the impact of two variables, namely the molar ratio of methanol to oil and the flow rate (ml/min), on the FAME yield were studied. Likewise, for the batch process, the reaction was carried out in a CSTR reactor using KOH as a homogeneous catalyst. Moreover, the influence of the molar ratio of methanol to oil and of catalyst concentration (wt. %) on the FAME yield was investigated. For both the batch and continuous process, FAME yield was optimized by using the Design Expert (Ver. 7.0.0) software. The optimum conditions for the continuous method were reported as follows: a molar ratio of methanol to oil of 11.75:1, a flow rate of 1.07 ml/min, and a temperature of 50oC. Under the optimum conditions, a FAME yield of 94.2423% was achieved. For the batch process, a FAME yield of 95.0672% was reached under the optimum conditions of a molar ratio of methanol to oil of 9.12:1, a catalyst concentration of 1.52 wt. %, a temperature of 40oC, an agitation rate of 650 rpm, and a reaction time of 60 minutes.
Environmental Impacts and Sustainability
Mohammad Ameri; Keivan Salimi
Abstract
In recent decades, excessive using fossil fuels has been resulted in emitting greenhouse gases such as CO2, consequently, environmental pollution. In this study, the techno-economic analysis of the CCHP/PV hybrid system application for a sample building was examined to reduce the environmental pollution ...
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In recent decades, excessive using fossil fuels has been resulted in emitting greenhouse gases such as CO2, consequently, environmental pollution. In this study, the techno-economic analysis of the CCHP/PV hybrid system application for a sample building was examined to reduce the environmental pollution and primary energy consumption of the buildings. The life-cycle cost analysis was utilized as a robust economic criterion. To investigate the effect of climate conditions on the system performance, five cities of Bandar Abbas, Ahvaz, Tehran, Bandar Anzali, and Ardebil were considered and evaluated. The results showed that the pollution emission rate and primary energy consumption of the building were declined by the CCHP/PV system up to 10.14 % and 26.52 % for the coldest climates, respectively. Moreover, an increase of 33.33 % was observed compared to the conventional system due to its high initial investment. However, the sensitivity analysis of energy tariffs, as well as equipment prices indicated favorable results and a bright horizon for these systems.
Renewable Energy Resources and Technologies
Fariba Heidarpour; Ghazanfar shahgholian
Abstract
The sustainability of hydraulic turbines was one of the most important issues considered by electrical energy provider experts. Increased electromechanical oscillation damping is one of the key issues in the turbines sustainability. Electromechanical oscillations, if not quickly damp, can threaten the ...
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The sustainability of hydraulic turbines was one of the most important issues considered by electrical energy provider experts. Increased electromechanical oscillation damping is one of the key issues in the turbines sustainability. Electromechanical oscillations, if not quickly damp, can threaten the stability of hydraulic turbines and causes the separation of different parts of the network form each other, specifically ejecting the generators from the turbine. In this paper, a Round-robin scheduling algorithm was used based on a neural network and simulations were investigated by several methods. Thus, using the designed Round-robin scheduling algorithm, we can find three parameters simultaneously. So optimal outputs can determine by these three parameters, which would be investigated as the optimal output range. In other words, besides using other algorithms capability, it can eliminate some of their disadvantages. The Round-robin scheduling algorithm is more suitable for large and extensive systems, due to reducing the number input variables and have a non-linear and resistant structure at the same time, This algorithm can actually use for optimizing any other controlling methods.
Renewable Energy Economics, Policies and Planning
Younes Noorollahi; Fatemeh Pourghasem; Hossein Yousefi
Abstract
Baseline data represent one of the important stages of Environmental Impact Assessment (EIA) procedure that describes the existing environment of the study area and surrounding areas in enough detail to allow the environmental impacts of the proposed area to be accurately and adequately assessed, and ...
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Baseline data represent one of the important stages of Environmental Impact Assessment (EIA) procedure that describes the existing environment of the study area and surrounding areas in enough detail to allow the environmental impacts of the proposed area to be accurately and adequately assessed, and future changes and effects can be measured. Baseline data may be inaccurate, difficult to obtain or non-existent in Iran as a developing country, and it involves huge and diverse environmental data of a spatial nature in the EIA process. Therefore, a useful and effective geographic information system (GIS) approach is developed to integrate geodatabase by acquiring and handling environmental data from different sources related to the proposed project area for the EIA procedure. Based on this approach, a comprehensive geodatabase for baseline data of EIA procedure, called Baseline Geodatabase (BGDB), is designed. The BGDB includes feature datasets (projects, climatology and air quality, hydrology, pedology, general location map of the study area, geology, noise, biology, and socio-economic-cultural data) and tables (fauna). For example, the BGDB for Sabalan geothermal project area, Iran as a case study is developed. This paper provides a practical tool to facilitate the EIA process, environmentally sustainable management, and to support decision-making for environmental specialists and managers in the present and future of the proposed project area.
Renewable Energy Resources and Technologies
Negin Maftouni; Kiana Motaghedi
Abstract
Traditional fossil fuels, which are also depleting cause environmental problems. A significant portion of global energy consumption is due to building air conditioning systems. Nowadays, considerable attention is drawn to renewable and sustainable energy sources to support the energy requirements of ...
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Traditional fossil fuels, which are also depleting cause environmental problems. A significant portion of global energy consumption is due to building air conditioning systems. Nowadays, considerable attention is drawn to renewable and sustainable energy sources to support the energy requirements of buildings. In this study, a solar absorption chiller was designed for a three-floor residential building in hot and arid climate. At first, thermal loads in the building were calculated using Carrier software. The material and color of the exterior walls, as well as window types, were changed to reduce the heat transfer coefficient and get an optimum design. Results indicate that by using the optimum design, maximum heating load reduction and maximum cooling load reduction can be achieved with approximate rates of 37 % and 12 %, respectively. Considering safety factor and based on the maximum cooling load, a single-effect LiBr-water solar absorption chiller was designed for the optimum building. Two different scenarios were suggested using two types of flat plate and evacuated tube collector. Results show that in the case of evacuated tube collector the net collector area of 254.18 m2 is sufficient to supply the cooling power. Implementing flat plate collectors would result in occupying an area of 398.5 m2. Regarding the limitation of total area of roof and efficiency issues, the evacuated tube collector is the best option.
Renewable Energy Resources and Technologies
Narges Barzanooni; Hamid Reza Haghgou
Abstract
In this paper, on the basis of Green comprehensive Plan at Hakim Sabzevari University of Sabzevar, Iran, using of active solar systems at dining hall has been evaluated. On the basis of solar measured data and some solar models and relations, solar energy on the various surfaces and tilts are ...
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In this paper, on the basis of Green comprehensive Plan at Hakim Sabzevari University of Sabzevar, Iran, using of active solar systems at dining hall has been evaluated. On the basis of solar measured data and some solar models and relations, solar energy on the various surfaces and tilts are evaluated. Then electricity and thermal energy consumption are measured and new efficient lighting systems are introduced. Then photovoltaic/thermal panels and one ended evacuated tube solar collector for façade and rooftop installation are chosen. Results shows that 36683 Nm 3 /year natural gas and 87.6 tone/year pollutant are reduced. Payback time of the system based on internal energy carrier and export electricity price are 21.3 and 3.9 years respectively.
Renewable Energy Resources and Technologies
Bahman Heydari; Shahin Rafiee; Elham Abdollahzadeh Sharghi; Seyed Saeid Mohtasebi
Abstract
The aromatic and dark-colored spearmint essential oil wastewater (SEOW) generally contains a large amount of organic matter, including chemical oxygen demand (COD), phenolic compounds, and inorganic contents. In this study, the pollutant removal performance and biogas production rate of an up-flow anaerobic ...
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The aromatic and dark-colored spearmint essential oil wastewater (SEOW) generally contains a large amount of organic matter, including chemical oxygen demand (COD), phenolic compounds, and inorganic contents. In this study, the pollutant removal performance and biogas production rate of an up-flow anaerobic sludge blanket (UASB) reactor used for the treatment of SEOW were investigated. During the 102 days UASB operation at hydraulic retention time of 60 hours, the organic loading rate (OLR) was increased from 0.14 to 2.69 kg COD/m3.d by increasing the influent SEOW concentration. With increasing OLR from 0.14 to 2.69 kg COD/m3.d, the concentrations of COD and phenol in the influent of the UASB reactor increased to 6720±383 mg/L and 383±88 mg/L, respectively. At OLR equal to 2.69 kg COD/m3.d, the steady-state average removal efficiencies of COD and phenol were 72.0±1.4 and 63.1±6.7 %, respectively. The stability of the anaerobic system was confirmed by the average steady-state ratios of the volatile fatty acid/alkalinity and pH in the UASB reactor, which were less than 0.4 and 7.5±0.1, respectively, at different OLRs. The optimum OLR was found to be 2.69 kg COD/m3.d, where 26.9±1.7 L/d production of biogas containing 63.0±5.2 % and 22.4±4.2 % methane and carbon dioxide, respectively, was obtained. Moreover, at OLR equal to 2.69 kg COD/m3.d, the biogas yield and net heating value were 462.2±46.9 L/kg CODremoved and 24.7±5.2 MJ/m3, respectively. The results of the current study reveal the substantial potential of the UASB reactor in terms of pollutant removal performance and biogas production for the treatment of SEOW.
Renewable Energy Resources and Technologies
Tazkieh Gilvari; Behzad Aghabarari; Mohammad Pazouki
Abstract
This study investigated the esterification reaction of different carboxylic acids (Acetic acid, Palmitic acid, and Oleic acid) and ethanol by ZnO, Al2O3-ZnOmixed oxide, and phosphotungestic acid (10 wt %) immobilized on the Al2O3-ZnOmixed oxide. The heterogeneous catalysts were characterized by XRD, ...
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This study investigated the esterification reaction of different carboxylic acids (Acetic acid, Palmitic acid, and Oleic acid) and ethanol by ZnO, Al2O3-ZnOmixed oxide, and phosphotungestic acid (10 wt %) immobilized on the Al2O3-ZnOmixed oxide. The heterogeneous catalysts were characterized by XRD, BET, FE-SEM, and EDX techniques. Optimum yield was achieved by using 10 % HPW/Al2O3-ZnOas the best catalyst, and the effects of the amount of catalyst, molar ratio of acid to alcohol, reaction temperature, and time were investigated to ensure the ideal yield of esterification reaction of acetic acid and ethanol. The results showed that the esterification of acetic acid to its ethyl ester was carried out in 3.5 hours, with an alcohol-to-acid-molar ratio of 2 and a temperature of 80 ˚C with yield 98 %. Moreover, the 10 % HPW/Al2O3-ZnOcatalystshowed well activity in biodiesel production by the esterification of palmitic and oleic acids and the reaction yield did not decrease with an increase in alkyl chain lengthin acid molecules, remarkably.
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 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
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
Ehsan Hosseini; Neda Behzadfar; Mahnaz Hashemi; Majid Moazzami; Majid Dehghani
Abstract
Wind turbines can be controlled by controlling the generator speed and adjusting the blade angle and the total rotation of a turbine. Wind energy is one of the main types of renewable energy and is geographically extensive, scattered and decentralized and is almost always available. Pitch angle control ...
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Wind turbines can be controlled by controlling the generator speed and adjusting the blade angle and the total rotation of a turbine. Wind energy is one of the main types of renewable energy and is geographically extensive, scattered and decentralized and is almost always available. Pitch angle control in wind turbines with Doubly Fed Induction Generator (DFIG) has a direct impact on the dynamic performance and oscillations of the power system. Due to continuous changes in wind speed, wind turbines have a multivariate nonlinear system. The purpose of this study is to design a pitch angle controller based on fuzzy logic. According to the proposed method, nonlinear system parameters are automatically adjusted and power and speed fluctuations are reduced. The wind density is observed by the fuzzy controller and the blade angle is adjusted to obtain appropriate power for the system. Therefore, the pressure on the shaft and the dynamics of the turbine are reduced and the output is improved, especially in windy areas. Finally, the studied system is simulated using Simulink in MATLAB and the output improvement with the fuzzy controller is shown in the simulation results compared to the PI controller. Fuzzy control with the lowest cost is used to control the blade angle in a wind turbine. Also, in this method, the angle is adjusted automatically and it adapts to the system in such a way that the input power to the turbine is limited. Compared to the PI controller, by calculating different parameters, the power quality for fuzzy controller is enhanced from 2.941 % to 4.762 % for wind with an average speed of 12 meters per second.
Renewable Energy Resources and Technologies
Babak Keyvani; Bahador Fani; Hamed Karimi; Majid Moazzami; Ghazanfar Shahgholian
Abstract
Conventional droop control method has been widely adopted for power sharing between Distributed Generators (DGs) in microgrids. However, the mismatched feeder impedance of the Voltage-Sourced Inverters (VSI) may generate reactive power sharing error during islanding operation of a microgrid. In this ...
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Conventional droop control method has been widely adopted for power sharing between Distributed Generators (DGs) in microgrids. However, the mismatched feeder impedance of the Voltage-Sourced Inverters (VSI) may generate reactive power sharing error during islanding operation of a microgrid. In this paper, an improved droop control method is suggested to improve the reactive power sharing accuracy. In the proposed method, the slope correction of the droop characteristics is performed in such a way that the reactive power sharing error is reduced. In this method, the errors of reactive power sharing are detected by applying a clear signal to the microgrids and, then, by adding a new term to the P-ω and correcting the slope of Q-E, the reactive power sharing is done. In this way, the proposed method can successfully improve the reactive power sharing accuracy even at different X/R ratios. Another feature of this method is its high operation speed compared to the other methods of droop feature correction. The simulation results for a prototype microgrid point to the efficiency and flexibility of the proposed method.
Renewable Energy Resources and Technologies
Mehdi Jahangiri; Farhad Raeiszadeh; Reza Alayi; Atabak Najafi; Ahmad Tahmasebi
Abstract
Rural tourism is an important factor in achieving economic, social, and cultural development. Given that villages in Iran do not have access to permanent electricity or are associated with high power outages, the provision of sustainable electricity through renewable energy can cause more tourists to ...
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Rural tourism is an important factor in achieving economic, social, and cultural development. Given that villages in Iran do not have access to permanent electricity or are associated with high power outages, the provision of sustainable electricity through renewable energy can cause more tourists to choose these villages as their ultimate goal. Therefore, in this paper, for the first time, a hybrid system has been evaluated based on solar energy in 10 tourism target villages in Iran using HOMER software. This study investigated the design of the system with real and up-to-date data on equipment and fossil fuel prices taking into account transportation costs as well as a comprehensive study of energy-economic-environmental with electricity generation approach to the development of rural tourism. The results demonstrated that for the studied stations, the LCOE parameter was in the range of $ 0.615-0.722, the percentage of power supply by solar cells was in the range of 90-99 %, and the prevention of pollutants was 33.9-277 kg/year. According to the results, Meymand village is the most suitable and Mazichal village is the unsuitable station in the field of energy supply required by solar cells. The production pollution in the studied stations is mainly CO2 and results from the operational phase of the project and its amount is 979.5 kg/year. Given that the rural tourism has grown and become a solution for development, the authors hope that the present work results can be used as a perspective to help energy and rural tourism decision-makers.
Renewable Energy Resources and Technologies
Roxana Isabel Bernaola Flores; Carmen Elena Flores Barreda; Diana Carolina Parada Quinayá; Ursula Fabiola Rodríguez Zúñiga
Abstract
Reducing the demand for fossil fuels and the derived products can be achieved through the development of alternative energy sources. This work presents a countrywide study of the energy potential of lignocellulosic biomass sourced from agro-industrial by-products in the country of Peru. Ranking of the ...
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Reducing the demand for fossil fuels and the derived products can be achieved through the development of alternative energy sources. This work presents a countrywide study of the energy potential of lignocellulosic biomass sourced from agro-industrial by-products in the country of Peru. Ranking of the crops that produce the most waste was followed by an energy potential evaluation of carbohydrate conversion and thermochemical conversion. The crops with high calorific values were sugar cane bagasse, wood waste, and coffee husk. The energy potential of the principal lignocellulosic by-products, in terms of tons of oil equivalents per year, resulted from rice straw at 1.45 M, followed by corn residue at 1.13 M and sugar cane residue at 1.10 M. The northern region of Peru generated the highest quantities of rice (straw and husk), banana (husk and rachis), and sugar cane (bagasse and straw) by-products and the southern regions generated the greatest quantities of quinoa residue, all of which could be used as raw materials for biofuels and aggregates for materials. These results indicate that theoretically, this readily available biomass could meet the country's energy demands while promoting sustainability and national energy security.
Renewable Energy Resources and Technologies
Krishnarao Rajaram Patil
Abstract
The present study aims to develop different strategies for better utilization of oxygenated Diethyl ether and ethanol as supplementary fuels by blending them with biodiesel as the base fuel in CI engines. The used biodiesel used was readily available Karanja Oil Methyl Ester (KOME), its scientific name ...
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The present study aims to develop different strategies for better utilization of oxygenated Diethyl ether and ethanol as supplementary fuels by blending them with biodiesel as the base fuel in CI engines. The used biodiesel used was readily available Karanja Oil Methyl Ester (KOME), its scientific name being Pongamia Pinnata. Initially, 5 %, 10 %, 15 %, and 20 % amounts of ethanol (volume) were mixed with biodiesel. Further, the optimum selected blend BE15 was mixed with 5 %, 10 %, 15 %, and 20 % DEE by volume to make the ternary blend. This DEE-ethanol-biodiesel blend was tested on the same engine under the same conditions. The experimental results exhibited that the DEE-ethanol-biodiesel ternary blend, BE15DE10, mitigated BTE by 8.89 % and the smoke, NOx, and CO emissions by 15.66 %, 50.7 %, and 18.5 %, respectively, compared with neat biodiesel. The HC emission exhibited a slightly increasing trend. The results summarize the trade-off between smoke and NOx reduction using DEE and ethanol oxygenated fuels. The addition of ethanol by 15 % and DEE up to 10 % by volume to biodiesel could be considered the most favorable blend without any significant modifications in the CI engine.
Renewable Energy Economics, Policies and Planning
Zeinab Ghasemi Sangi; Abbas Tarkashvand; Hanieh Sanaeian
Abstract
The height of buildings is one of the main features of urban configuration that affects energy consumption. However, to our knowledge, the complexity of relationships between the height parameters and energy use in urban blocks is poorly understood. In this context, the present study investigates the ...
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The height of buildings is one of the main features of urban configuration that affects energy consumption. However, to our knowledge, the complexity of relationships between the height parameters and energy use in urban blocks is poorly understood. In this context, the present study investigates the effect of the height distribution of buildings located in a residential complex on the energy consumption required for cooling and heating. This research simulates different possible layouts through computational software. For this purpose, first, the density of a residential complex was determined based on the rules and regulations of Tehran city and according to the site dimensions and certain site coverage. Then, the required building density was distributed in different layouts based on their diversity at different heights. The product of this stage involved 7 different layouts in which the height varied from 1 floor to the maximum number calculated in each part of the simulation. In the next step, the annual energy consumption for cooling and heating the complex was calculated for each of these layouts and compared with each other. The parametric generative model was created in the Grasshopper plugin from Rhino software, and the energy consumption was evaluated with the Honeybee plugin over one year. Also, the research findings were validated through DesignBuilder software using the EnergyPlus engine. The results of the energy simulation indicate that the height distribution of the blocks can have a significant effect on energy consumption. In the optimal case, proper layout reduces the annual cooling and heating energy consumption by 28 % and 13 %, respectively. Therefore, achieving an optimal value for each of the cooling and heating loads depends on the specific priorities and conditions of the design project. If the design project's priority is to reduce heating energy consumption, increasing the height and distributing the floors evenly between the blocks is a better answer. However, if the priority is to mitigate cooling energy consumption, the optimal layout can include low-rise blocks and a single very high-rise block.
