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.
Advanced Energy Technologies
Ali Mostafaeipour; Mojtaba Qolipour; Hossein Goudarzi; Mehdi Jahangiri; Amir-Mohammad Golmohammadi; Mostafa Rezaei; Alireza Goli; Ladan Sadeghikhorami; Ali Sadeghi Sedeh; Seyad Rashid Khalifeh Soltani
Abstract
Fuel cells are potential candidates for storing energy in many applications; however, their implementation is limited due to poor efficiency and high initial and operating costs. The purpose of this research is to find the most influential fuel cell parameters by applying the adaptive neuro-fuzzy inference ...
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Fuel cells are potential candidates for storing energy in many applications; however, their implementation is limited due to poor efficiency and high initial and operating costs. The purpose of this research is to find the most influential fuel cell parameters by applying the adaptive neuro-fuzzy inference system (ANFIS). The ANFIS method is implemented to select highly influential parameters for proton exchange membrane (PEM) element of fuel cells. Seven effective input parameters are considered including four parameters of semi-empirical coefficients, parametric coefficient, equivalent contact resistance, and adjustable parameter. Parameters with higher influence are then identified. An optimal combination of the influential parameters is presented and discussed. The ANFIS models used for predicting the most influential parameters in the performance of fuel cells were performed by the well-known statistical indicators of the root-mean-squared error (RMSE) and coefficient of determination (R2). Conventional error statistical indicators, RMSE, r, and R2, were calculated. Values of R2 were calculated as of 1.000, 0.9769, and 0.9652 for three different scenarios, respectively. R2 values showed that the ANFIS could be properly used for yield prediction in this study
Renewable Energy Economics, Policies and Planning
Mahdieh Rezagholizadeh; Majid Aghaei; Omid Dehghan
Abstract
Concerning environmental pollution issues derived from fossil energy consumption, the application of renewable energies plays an important role in countries, especially in their energy sector policymaking. Since determining the relationship between different variables and renewable energy not only has ...
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Concerning environmental pollution issues derived from fossil energy consumption, the application of renewable energies plays an important role in countries, especially in their energy sector policymaking. Since determining the relationship between different variables and renewable energy not only has significant policy applications in energy sector but also is necessary in achieving sustainable development goals, this study assesses the impact of effective factors on the development of renewable energy consumption in Iran with emphasis on the role of foreign direct investment (FDI) and financial sector development (especially stock market development). This study applies Auto-Regressive Distributed Lag (ARDL) bounding test method over the period of 1978-2016. The research findings show that there is a causal relationship between foreign direct investment and the stock market and renewable energy consumption in Iran such that the increase of foreign direct investment and stock market development will increase the consumption of renewable energies in Iran. On the other hand, a growth in renewable energies consumption will significantly reduce CO2 emission in the long run. Besides, increasing FDI and stock market development will raise the economic growth of a country and, in return, increase CO2 emission.
Renewable Energy Resources and Technologies
Amin Habibzadeh; Samad Jafarmadar
Abstract
A considerable amount of waste heat is produced by internal combustion engines. Bottoming cycle application of Organic Rankine Cycles (ORC) is one of the promising technologies that recuperates the waste heat of engines. A lot of engine waste heat is released into the environment. There are a lot of ...
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A considerable amount of waste heat is produced by internal combustion engines. Bottoming cycle application of Organic Rankine Cycles (ORC) is one of the promising technologies that recuperates the waste heat of engines. A lot of engine waste heat is released into the environment. There are a lot of working fluids that can be applied in these cycles. As the engine waste heat temperature is extremely high, finding a suitable working fluid, which operates properly in the combined cycle, is challenging. In this paper, the thermodynamic analysis of ten working fluids including cyclohexane, HFE7000, HFE7100, n-hexane, n-pentane, R11, R123, R134a, R141b, and R245fa is conducted to observe the influence of different parameters on the system performance and introduce the most appropriate working fluid. Results indicated that, in the studied ranges, R134a had the best performances since (a) its thermal and exergy efficiencies were 17.39 % and 17.34 %, respectively; (b) the thermal efficiency of the engine increased by 9 %, and the net power of the system reached 7.5 kW. Furthermore, there was about 9 % reduction in fuel consumption. On the other hand, among the studied working fluids, cyclohexane operates as the least suitable one by possessing the minimum amounts.
Environmental Impacts and Sustainability
Mohammad Hossein Jahangir; Mahnaz Abolghasemi; Seyedeh Mahsa Mousavi Reineh
Abstract
Drought is considered as a destructive disaster that can have irreversible effects on different aspects of life. In this study, artificial neural network was used as a powerful means of modeling nonlinear and indefinite processes in order to simulate drought intensities at 7 synoptic stations of Khorasan ...
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Drought is considered as a destructive disaster that can have irreversible effects on different aspects of life. In this study, artificial neural network was used as a powerful means of modeling nonlinear and indefinite processes in order to simulate drought intensities at 7 synoptic stations of Khorasan Razavi from more than 35 years ago up to the year 2014. Input data were the calculations of the two indicators of PNPI and SPI by DIC software, and the output layer (drought intensity) was taken to the Matlab software and employed as the teaching data (from 25 years), experiment (from 5 years), and validation (from another 5 years). The 3-9-1 structure of the network of layers had the maximum accuracy with the error rate of less than 2 % and high correlation (more than 90 %). After trial and error for each station through sigmoid stimulation function in the Perceptron network, it was observed that the stations of Mashhad and Quchan had the minimum error and the maximum error was related to the station of Neyshabur. The results of comparisons and observations showed that the artificial neural network had high efficiency in simulation of the data. The obtained correlation amount of 0.999 for the base station represented the small error of the model in prediction. Drought forecasting was performed in this study by the trained algorithm in the artificial neural network without using the observation data. The results showed that rainfall, temperature, and speed models had a positive role in forecasting the provinces that would experience drought. Due to its lower amount of error, SPI indicator was selected for mapping, the findings of which showed that the highest drought intensity belonged to the near normal to normal wet lands.
S. Zeinali Heris; Farhad Oghazian; Mahmoud Khademi; Effat Saeedi
Abstract
In this study, the convective heat transfer and pressure drop in laminar flow of Al2O3/water and CuO/water nanofluids through square and triangular cross-sectional ducts have been numerically investigated using new technique. It has been assumed that there is constant heat flux boundary condition at ...
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In this study, the convective heat transfer and pressure drop in laminar flow of Al2O3/water and CuO/water nanofluids through square and triangular cross-sectional ducts have been numerically investigated using new technique. It has been assumed that there is constant heat flux boundary condition at walls. In addition, to include the presence of nanoparticles, the dispersion model has been used, and the system was solved numerically. Results show that by increasing the volumetric concentration and decreasing the size of nanoparticles, Nusselt number has been enhanced. Also, the Nusselt number increases by increasing the Reynolds number. In all cases, it has been observed that heat transfer coefficient of nanofluid increases in comparison with heat transfer coefficient of pure water. The results show that by adding nanoparticles, pressure drop increases in ducts. In square and triangular ducts, pressure drop is higher when we use CuO/water nanofluid instead of Al2O3/water nanofluid. In the same way, pressure drop increases by increase of faces of non-circular ducts.
Hossein Vaheed; S. Mohammad Mousavi; S. Abbas Shojaosadati; Hasan Galip
Abstract
Regarding some reported antimicrobial properties of tannins; Zymomonas mobilis was used to obtain ethanol from tannin-reduced carob pod extract (TR-CPE). Culture of 50 mL volume containing 7.5 g sugar at pH 5.5 and 0.03 g bacterial inoculums with shaking at 80 rpm was used. Using response surface methodology ...
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Regarding some reported antimicrobial properties of tannins; Zymomonas mobilis was used to obtain ethanol from tannin-reduced carob pod extract (TR-CPE). Culture of 50 mL volume containing 7.5 g sugar at pH 5.5 and 0.03 g bacterial inoculums with shaking at 80 rpm was used. Using response surface methodology (RSM), the maximum ethanol concentration of 5.34 % w/v (higher than that reported earlier, 4.01% w/v) was obtained at the optimized addition levels of yeast extract, peptone, and fermentation time; 0.13 g, 0.62 g, and 43.78 h, respectively. Carob pods extract (CPE) containing 62.23 gl-1 sugar was treated with 3 gl-1 gelatin to decrease its tannin content by 57.87 %. Sugar loss was not observed during gelatin treatment. The results revealed that there was no significant difference in ethanol production, yield, and productivity between TR-CPE and non-TR-CPE. In conclusion, tannin showed no inhibiting effect to maximum ethanol production by Zymomonas mobilis.
