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Showing papers in "international journal of energy and environmental engineering in 2013"


Journal ArticleDOI
TL;DR: In this article, the effect of woody biochar amendment (yellow pine from pyrolysis at 400°C) on the water holding capacity of loamy sand soil with different mixture rates was investigated.
Abstract: With the rise in global population and increased agricultural requirements comes an increasing need for freshwater. Currently, it is estimated that approximately 75% of fresh water consumption is for the growth of agricultural crops, and only 10% to 30% of this water is actually made available to plants. It is widely accepted that farming practices which rely heavily on chemical fertilizers and unsustainable land management practices have led in many regions to infertile sandy soils with reduced water holding capacity and insufficient amounts of organic matter. Combined with increasing global population, the need to better manage fresh water use, particularly agricultural usage, is paramount. The use of biochar as a soil amendment has been suggested as a way to increase water holding capacity, but only limited quantitative studies exist in terms of the effectiveness of biochar in increasing a soil's water holding capacity. The main purpose of this study was to determine the effect of woody biochar amendment (yellow pine from pyrolysis at 400°C) on the water holding capacity of loamy sand soil with different mixture rates. Results show a doubling in water holding capacity by mass using a 9% mixture of biochar (equivalent to 195 metric ton/ha), which is an agriculturally relevant concentration. High percentage mixtures of biochar increase water holding capacity dramatically. These results suggest the use of biochar has potential to mitigate drought and increase crop yields in loamy sand soil.

161 citations


Journal ArticleDOI
TL;DR: In this article, the authors evaluate and compare environmental impacts of various food waste management systems: anaerobic digestion, co-digestion with sewage sludge, and volume reduction using a garbage dryer followed by incineration from generation to final disposal.
Abstract: This study is aimed to evaluate and compare environmental impacts of various food waste management systems: anaerobic digestion, co-digestion with sewage sludge, and volume reduction using a garbage dryer followed by incineration from generation to final disposal. An environmental credit using life cycle assessment was employed to compare by-products. The entire disposal process, namely discharge, collection, transportation, treatment, and final disposal, was included in the system boundary. The functional unit was 1 tonne of food waste from households for each treatment option. Global warming potential of the category indicator was selected to assess the environmental impact of food waste disposal options. The net global warming potential (environmental credit) of the options (wet based) was 33 kg of carbon dioxide equivalent (CO2-eq) for anaerobic digestion and �315 kg of CO2-eq for incineration by renewable energy production as electricity, thermal energy, and primary materials avoided. We found that dryer-incineration option was an available alternative for food waste recycling in a metropolitan area in Korea.

82 citations


Journal ArticleDOI
TL;DR: In this article, the authors investigated the optimization of biodiesel production from neem (Azadirachta indica) oil using a two-step transesterification process and determination of the qualities of the neem oil biodiesel.
Abstract: This work investigated the optimization of biodiesel production from neem (Azadirachta indica) oil using a two-step transesterification process and determination of the qualities of the neem oil biodiesel. This was with a view to establish its production and viability potentials. Biodiesel production was carried using a two-step transesterification process. The first step was carried out using 0.60 w/w methanol-to-oil ratio in the presence of 1% w/w H2SO4 as an acid catalyst in 1 h at 50°C. The second step was base (NaOH) transesterification of the product from the first step using conditions specified in the optimization design. The central composite design optimization conditions for the second step were temperature (45°C to 65°C), catalyst amount (0.45% to 1.45% w/w), reaction time (45 to 65 min), and methanol/oil molar ratio (1.5 to 7.5). The physicochemical properties of the neem biodiesel were carried out using standard methods, while the fatty acid profile was determined using gas chromatography. Optimized biodiesel yield of 89.69% was produced at reaction time of 65 min, catalyst amount of 0.95 g, temperature of 55°C, and methanol/oil molar ratio of 4.5:1. The values for the physicochemical properties are 0.05% moisture content, 0.9 specific gravity at 25°C, 5.5 mm2/S kinematic viscosity, 207 mg KOH/g, 70.7 g I2/100 g iodine value, 55.31 cetane number, 39.85 MJ/Kg calorific value, 4 pour point, 8 cloud point, and 110 flash point. These values conform to international standards, in particular, American Society Testing Materials (ASTM).

81 citations


Journal ArticleDOI
TL;DR: In this paper, the authors present a techno-economic assessment potential to utilize the energy obtainable from municipal solid waste (MSW) for the generation of electrical power, which is generally accepted as a renewable energy resource.
Abstract: The continued concerns over energy prices, increase in population, and climate change issues have led towards a need for alternative and new energy sources. Municipal solid waste (MSW) is generally accepted as a renewable energy resource. This research study presents a techno-economic assessment potential to utilize the energy obtainable from MSW for the generation of electrical power. The assessment was carried out for energy generation by thermochemical (incineration or combustion) and biochemical (landfilling and anaerobic digestion) processes and based on the available data from seven selected municipalities. Due to the broad scope of this topic, life cycle impact of waste management, social acceptance, policy aspects, and emission reduction or fossil fuel offset are not considered and are not part of the assessment. Results presented in tabular form indicate, for example, that the price of steam generated by a fluidized steam generator is in the range of US$0.018/kWht (Lagos) to US$0.044/kWh (Nsukka) and compares favorably with the typical cost of steam at US$0.015/kWh. Electrical power generation using a combined heat and power plant provides electricity at a cost that is in the range of US$0.017/kWhe (Lagos) to US$0.040/kWhe (Nsukka) and also compares well with the typical cost of electricity in Nigeria at US$0.14/kWhe (as of 2012).

79 citations


Journal ArticleDOI
TL;DR: In this article, the effect of species, particle size and compacting pressure on relaxed density and compressive strength in cleft of briquettes produced from sawdust of tropical hardwoods was investigated.
Abstract: Densification of biomass waste materials has provided a great boost to the utilization of wood and agricultural waste for domestic and industrial fuel. However, the processes involved in the production of this fuel make it more expensive than fossil fuel. This is because densification of wood waste into fuel briquettes is not simple. This paper reports the results of research conducted to determine the effect of species, particle size and compacting pressure on relaxed density and compressive strength in cleft of briquettes produced from sawdust of tropical hardwoods. Briquettes were made using a laboratory hydraulic press. Compacting pressure was varied from 10 to 50 MPa at an interval of 10 MPa. Species used were Triplochiton scleroxylon, Ceiba pentandra, Aningeria robusta, Terminalia superba, Celtis mildbreadii and Piptadenia africana. The results indicate that species, compacting pressure and particle size of sawdust at 5% level of significance have significant effect on the relaxed density and compressive strength in cleft of briquettes produced. The multiple correlation coefficient (R) and adjusted R 2 for the regression model between relaxed density of briquettes, and species density, particle size and compacting pressure were 0.93 and 0.87, respectively. Additionally, the multiple correlation coefficient and adjusted R 2 for the regression model between compressive strength of briquettes, and species density, particle size and compacting pressure were 0.83 and 0.69, respectively. The regression models suggest that species density, particle size and compacting pressure are good predictors of relaxed density and compressive strength in cleft of briquettes produced from sawdust of tropical hardwoods.

74 citations


Journal ArticleDOI
TL;DR: In this article, a statistical approach was employed to optimize biodiesel production from sesame oil in which response surface methodology was applied, and the effects of four variables, viz. reaction temperature, catalyst amount, reaction time, and methanol/oil molar ratio, and their reciprocal interactions were determined.
Abstract: Statistical approach was employed to optimize biodiesel production from sesame oil in this work. Precisely, response surface methodology was applied, and the effects of four variables, viz. reaction temperature, catalyst amount, reaction time, and methanol/oil molar ratio, and their reciprocal interactions were determined. Central composite rotatable design was used to generate a total of 30 individual experiments, which were designed to study the effects of these variables during alkali-catalyzed methanolysis of sesame oil. A statistical model predicted the highest conversion yield of sesame biodiesel to be 99.71% at the following optimized variable conditions: reaction temperature of 63°C, catalyst amount of 1.04 wt.%, and methanol/oil molar ratio of 6.24, with a reaction time of 51.09 min. Using these variables under experimental condition in four independent replicates, an actual biodiesel yield of 98.36% was accomplished. The fuel properties of biodiesel produced were found to be within the ASTM D6751 and DIN EN 14214 biodiesel specifications.

65 citations


Journal ArticleDOI
TL;DR: A 10.3kW single-cylinder water-cooled direct-injection diesel engine was evaluated using blends of biodiesel (B10 and B20) obtained from a mixture of mahua and simarouba oils (50:50) with high-speed diesel (HSD) in terms of brake specific fuel consumption, brake thermal efficiency, and exhaust gas temperature and emissions such as CO, HC, and NOx as mentioned in this paper.
Abstract: A 10.3-kW single-cylinder water-cooled direct-injection diesel engine was evaluated using blends of biodiesel (B10 and B20) obtained from a mixture of mahua and simarouba oils (50:50) with high-speed diesel (HSD) in terms of brake specific fuel consumption, brake thermal efficiency, and exhaust gas temperature and emissions such as CO, HC, and NOx. Based on performance and emissions, blend B10 was selected for long-term use. Experiments were also conducted to assess soot deposits on engine components, such as cylinder head, piston crown, and fuel injector tip, and addition of wear metal in the lubricating oil of diesel engine when operated with the biodiesel blend (B10) for 100 h. The amount of soot deposits on the engine components was found to be, on average, 21% lesser for B10-fueled engine as compared with HSD-fueled engine due to better combustion. The addition of wear metals such as copper, zinc, iron, nickel, lead, magnesium, and aluminum, except for manganese, in the lubricating oil of B10-fueled engine after 100 h of engine operation was found to be 11% to 50% lesser than those of the HSD-fueled engine due to additional lubricity.

62 citations


Journal ArticleDOI
TL;DR: In this article, a mixed-mode solar dryer with forced convection using smooth and rough plate solar collector was constructed based on preliminary investigations under controlled condition of drying experiments, and the results of experiments to compare the performance of the smooth and the roughed plate collector.
Abstract: Based on preliminary investigations under controlled condition of drying experiments, a mixed-mode solar dryer with forced convection using smooth and rough plate solar collector was constructed. This paper describes the development of dryer considerations followed by the results of experiments to compare the performance of the smooth and the roughed plate collector. The thermal performance of solar collector was found to be poorer because of low convective heat transfer from the absorber plate to air. Artificial rib roughness on the underside of the absorber plate has been found to considerably enhance the heat transfer coefficient. The absorber plate of the dryer attained a temperature of 69.2°C when it was studied under no-load conditions. The maximum air temperature in the dryer, under this condition, was 64.1°C. The dryer was loaded with 3 kg of grapes having an initial moisture content of 81.4%, and the final desired moisture content of 18.6% was achieved within 4 days while it was 8 days for open sun drying. This prototype dryer was designed and constructed to have a maximum collector area of 1.03 m 2 . This solar dryer been be used in experimental drying tests under various loading

55 citations


Journal ArticleDOI
TL;DR: In this article, a series of wind tunnel investigations on semi-cylindrical three-bladed Savonius rotor scale models with different overlap ratios and without overlap were conducted in front of a low-speed subsonic wind tunnel at different Reynolds numbers.
Abstract: The purpose of this research work is to investigate experimentally and computationally the feasibility of improving the performance of the vertical-axis Savonius wind turbine. The authors first performed a series of wind tunnel investigations on semi-cylindrical three-bladed Savonius rotor scale models with different overlap ratios and without overlap. These experiments were conducted in front of a low-speed subsonic wind tunnel at different Reynolds numbers. Pressures around the concave and convex surfaces of each blade, as well as the static torque for the rotor models, were measured. Using these experimental data, the authors calculated aerodynamic characteristics such as drag coefficients, static torque coefficients, and power coefficients. The authors then performed computational fluid dynamics (CFD) simulations using the commercial CFD software FLUENT and GAMBIT to analyze the static rotor aerodynamics of those models. The experimental and computational results were then compared for verification. Three different models with different overlap ratios were designed and fabricated for the current study to find the effect of overlap ratios. The results from the experimental part of the research show a significant effect of overlap ratio and Reynolds number on the improvement of aerodynamic performance of the Savonius wind turbine. At higher Reynolds number, the turbine model without overlap ratio gives better aerodynamic coefficients, and at lower Reynolds number, the model with moderate overlap ratio gives better results.

52 citations


Journal ArticleDOI
TL;DR: In this article, the levelized cost of electricity (LCOE) and present value cost (PVC) methods for six locations selected across all the geopolitical zones of Nigeria were examined.
Abstract: Technical electricity generation assessment and economic analysis of six wind energy conversion systems in the categories small, medium, and large (with power ratings of 20, 35, 275, 500, 1,000, and 2,000 kW) were examined in this study. Electricity cost values were estimated based on the levelized cost of electricity (LCOE) and present value cost (PVC) methods for six locations selected across all the geopolitical zones of Nigeria. This was done using wind speed data that span between 25 and 37 years, measured at the height of 10 m. The result showed that the annual average energy output ranges from 2.242 MW h in Uyo with P10-20 turbine to 12,521.55 MW h in Kano using Vestas V80-2 MW wind turbine. Furthermore, of all the selected sites, Kano gave the least costs of electricity production per kilowatt hour with Vestas V80-2 MW model at 67-m hub heights, while the highest is obtained in Uyo with GEV-HP (1 MW) model at 70-m hub heights for the LCOE and PVC height for both the LCOE and PVC methods. In addition, sensitivity of the selected parameters to the levelized cost of electricity was also carried out.

51 citations


Journal ArticleDOI
TL;DR: In this paper, an innovative methodology to exploit wind flow fields, calculated by means of computational fluid dynamic (CFD) codes in urban environments, within the geographical information system (GIS) platform was proposed.
Abstract: Among renewable energy sources, the electrical generation from micro-wind turbines has not yet disclosed its huge potential especially in urban settings. Increasing the spread of micro-wind turbines not only promotes the decentralized generation of energy, but also helps tackle fuel poverty and to achieve reductions in the emission of greenhouse gases (GHGs). This work proposes an innovative methodology to exploit wind flow fields, calculated by means of computational fluid dynamic (CFD) codes in urban environments, within the geographical information system (GIS) platform. In this way, the platform of users is amplified, even non-specialist users, that can utilize wind data to evaluate the potential production of electricity using micro-wind turbines. A pilot study was conducted for assessing the applicability of the approach in a Sicilian city. The results of this case study show the energy yield produced from a building-mounted wind turbine (BUWT). The developed methodology permits to enrich the information usually stored in the GIS platform allowing to supply useful information about suitable sites where micro-wind energy plants can be installed and to assess the production of renewable energy in the urban settings.

Journal ArticleDOI
TL;DR: In this article, a set of data recorded from a pryanometer located on latitude 6.45° north of the equator was used to generate average monthly radiation over the latitudes.
Abstract: This work optimises the collection of solar energy within the period of its availability in order to increase its utilisation and also to enhance performance of heating systems that depend on it through appropriate determination of optimum solar collector tilt angles. Buoyancy-induced flow equation in solar collector pipe was established by continuity, energy and Navier–Stokes equations in cylindrical coordinates. Fundamental solar radiation equations were programmed to determine optimum tilt angles in locations within latitudes 1° and 14°. A set of data recorded from a pryanometer located on latitude 6.45° north of the equator was used to generate average monthly radiation over the latitudes. Graphs obtained from latitude 6° and 13° data were analysed to investigate solar radiation on some tilt angles. The optimum tilt angles for solar heating for periodic tracking of the sun in the region within latitudes 1° and 14° were predicted as ∅ + 25° for November, December and January; ∅ + 15° for February, September and October; ∅ − 15° for August; ∅ − 25° for May, June and July; and ∅ for March and April. The results of this work confirmed that solar radiation on tilted surface increases with latitude.

Journal ArticleDOI
TL;DR: In this article, the authors developed an integration of direct evaporative cooling tower with a solar chimney multi-zone thermal ventilation model to achieve a decrease in indoor temperatures that reach 10°C to 11.5°C compared to outdoor temperatures.
Abstract: Cooling buildings in summer is one of the main environmental problems for architects and occupants in many hot dry countries. The summer temperature during these countries reaches peaks of more than 40°C in some. Mechanical air conditioners can solve the problem, but they put a heavy strain on the electricity consumption. Egypt in general has rich sunny and clear skies. Therefore, these conditions encourage to enhance evaporating with natural ventilation and save energy. This paper develops an integration of direct evaporative cooling tower with a solar chimney multi-zone thermal ventilation model. Simulation is done using commercial couple multi-zone airflow under COMIS-TRNSYS software (Madison, WI, USA) to assess natural ventilation and indoor thermal comfort. The results show that the system generates 130.5 m 3 /h under the effect of solar radiation only and minimum 2 ACH without pressure coefficient which is considered the minimum requirement of ACH. The findings show that the new integrated system interacts with the building envelope and weather conditions to achieve a decrease in indoor temperatures that reach 10°C to 11.5°C compared to outdoor temperatures.

Journal ArticleDOI
TL;DR: In this article, the authors analyzed the electricity generation potential from wind at Kano, Nigeria (12.05°N; 08.2°E; altitude 472.5 m; air density 1.1705 kg/m3).
Abstract: This study analyzed the electricity generation potential from wind at Kano, Nigeria (12.05°N; 08.2°E; altitude 472.5 m; air density 1.1705 kg/m3). Twenty one years (1987 to 2007) monthly mean wind speed data at a height of 10 m were assessed from the Nigeria Meteorological Department, Oshodi. The data were subjected to different statistical tests and also compared with the two-parameter Weibull probability density function. The outcome shows that the average monthly wind speed ranged from 6.6 to 9.5 m/s. Seasonally, average wind speeds ranged between 6.6 to 8.5 m/s and 7.4 to 9.5 m/s for dry (October to March) and wet (April to September) seasons, respectively. Also, estimated monthly wind power ranged between 3.6 and 12.5 MWh/m2. The most probable and maximum energy carrying wind speeds were also determined and the two parameters of the Weibull statistics were found to lie between 2.1 ≤ k ≤ 4.9 and 7.3 ≤ c ≤ 10.7, respectively. These results indicate that wind speeds at Kano may be economically viable for wind-to-electricity at and above the height of 10 m. In addition, five practical turbine models were assessed for the site’s wind profile, with results suggesting strong economic viability.

Journal ArticleDOI
TL;DR: This review presents the perspective that in silico metabolic modelling based on genome-scale metabolic networks can be used for understanding the metabolisms of the anodic microorganisms and optimizes the performance of their metabolic networks for MFCs.
Abstract: A microbial fuel cell (MFC) is a device that uses microorganisms as biocatalysts to transform chemical energy or light energy into electricity. However, the commercial applications of MFCs are limited by their performance. This review presents the perspective that in silico metabolic modelling based on genome-scale metabolic networks can be used for understanding the metabolisms of the anodic microorganisms and optimizes the performance of their metabolic networks for MFCs. This is in contrast to conventional research that focuses on engineering designs and study of biological aspects of MFCs to improve interactions of anode and microorganisms. Four categories of biocatalysts - microalgae, cyanobacteria, geobacteria and yeast - are nominated for future in silico constraint-based modelling of MFCs after taking into account the cell type, operation mode, electron source and the availability of metabolic network specifications. In addition, the advantages and disadvantages of each organism for MFCs are discussed and compared.

Journal ArticleDOI
TL;DR: The sugar mill has become a multipurpose factory since it produces food, energy, and bio-fuels at present as discussed by the authors, and the key cause of this change is the use of sugarcane agro-industrial residues as feedstock for energy cogeneration and biofuel production.
Abstract: The sugarcane agro-industry is seen as a great opportunity for economic and industrial development in many sugarcane-producing countries. Important changes happening in recent decades have converted the sugar mill from being just a food producer into a diversified production factory. The sugar mill has become a multipurpose factory since it produces food, energy, and biofuels at present. The key cause of this change is the use of sugarcane agro-industrial residues as feedstock for energy cogeneration and biofuel production.

Journal ArticleDOI
TL;DR: In this article, the authors explored the potential of energy generation using the land above national road highways by constructing a roof structure, which can contribute to the energy generation without extra cost for the land.
Abstract: Energy generation using solar photovoltaic requires large area. As cost of the land is growing day by day, there is a strong requirement to use the available land as efficiently as possible. Here, we explored the potential of energy generation using the land above national road highways by constructing a roof structure. This space can contribute to the energy generation without extra cost for the land. It also results in energy efficiency, for example, improved vehicle movement and minimum energy for air conditioning of vehicles. Additionally, it also helps in minimum road repairs and longer vehicle tire life due to the effect of sun shade. Thus, the expenditure for wear and tear for road repairs is reduced considerably. From our modelling study, it is observed that the Ahmedabad-Rajkot highway can generate 104 MW of electricity (163 GWh of annual energy generation) and the Ahmedabad-Vadodara highway space can generate 61 MW of electricity (96 GWh of annual energy generation) for single-layer solar panels. If there are two layers of solar panels one over the other, the annual energy generation of the same highways, Ahmedabad-Rajkot and Ahmedabad-Vadodara, can be increased to 229 GWh and 140 GWh, respectively. If our concept is implemented throughout India, it not only increases the power generation to more than a few gigawatts of electricity but also has other various fringe benefits including longer road life, employment generation, reduced CO2 emission in environment, etc.

Journal ArticleDOI
TL;DR: In this article, a power regression model showing the relationship between photosynthetically active radiation (PAR) and Hg is presented for six Indian latitudes and for the entire year based on hourly and monthly average of the daily global radiation (Hg).
Abstract: Photosynthetically active radiation (PAR) as a component of solar radiation plays a major role in different applications dealing with plant canopies, biomass production and microalgae growth. The amount of PAR energy depends upon location, time of the year and atmospheric conditions. Understanding the PAR and its availability is very essential for modelling biological growth system. The objective of this study is to estimate PAR for latitudes ranging from 9° to 34° and for the entire year based on hourly and monthly average of the daily global radiation (Hg). Based on the estimated data, a power regression model showing the relationship between PAR and Hg is presented for six Indian latitudes. The ratios of hourly sum of PAR to Hg and monthly average of hourly global radiations (Ig) vary smoothly with significant seasonal variations and are influenced by several other local climatic conditions. The power regression equation between PAR and Hg obtained are as follows: (a) For 9° latitude, PAR = 0.040 (Hg) 0.924 , R 2 = 0.970, (b) 14° latitude, PAR = 0.029 (Hg) 0.952 , R 2 = 0.894, (c) 19° latitude, PAR = 0.256 (Hg) 0.748 , R 2 = 0.721, (d) 24° latitude, PAR = 0.159 (Hg) 0.775 , R 2 = 0.896, (e) 29° latitude, PAR = 0.052 (Hg) 0.886 , R 2 = 0.830 and (f) 34° latitude, PAR = 0.016 (Hg) 1.013 , R 2 = 0.768.

Journal ArticleDOI
TL;DR: In this paper, a study was made to obtain low cost building materials using industrial wastes (welding and furnace slags) in low-cost construction with adequate compressive strength.
Abstract: In this project, a study was made to obtain low cost building materials using industrial wastes (welding and furnace slags). The objective of the study is to use these wastes in low-cost construction with adequate compressive strength. Different fine aggregate replacements have been studied by substituting 5%, 10%, and 15% of slag. The waste material was substituted for replacement of fine aggregates and for the preparation of concrete blocks. In this project, we have followed Indian standard methods and arrived at the mix design for M25 grade concrete. Experimental studies were conducted only on plain cement concrete. The preliminary studies were conducted by mixing the slag with the cement concrete cubes of standard sizes. The building material specimens were analyzed for compressive strength as per IS code. For the test and other specifications, it can be concluded that the welding and furnace slags can increase the strength of the concrete. The optimum compressive strength of concretes after 28 days has been found to be 41 N/mm2 for 5% welding slag and 39.7 N/mm2 for 10% furnace slag replacements. The results show that 5% of welding and 10% furnace slags replacement with sand is very effective for practical purpose.

Journal ArticleDOI
TL;DR: In this paper, a simple and fast technique to determine appropriate location and size of distributed generation (DG) units in distribution network has been demonstrated, where vulnerable buses of the network are arranged rank-wise to form a priority list for allocation of DG units.
Abstract: Penetration of distributed generation (DG) units in distribution network has increased rapidly stimulated by reduced network power loss, improved bus voltage profile, and better power quality. Appropriate size and allocation of DG units play a significant role to get beneficial effects. The objective of this study is to demonstrate a simple and fast technique to determine appropriate location and size of DG units. A voltage stability indicator (VSI) is derived which can quantify the voltage stability conditions of buses in distribution network. According to VSI, vulnerable buses of the network are arranged rank-wise to form a priority list for allocation of DG units. To determine the size of DG units, a feed forward artificial neural network is prepared in MATLAB environment (The MathWorks, Inc., Massachusetts, USA). The effectiveness of the proposed methodology has been tested on a 52-bus radial distribution network. After appropriate allocation of DG units, voltage profiles of most of the buses are increased significantly. The results also indicated that the total loss of the distribution network has reduced by nearly 76.39%, and voltage stability conditions of buses are improved considerably. Voltage stability conditions of bus-13, bus-36, and bus-44 are raised by 23.16%, 29.23%, and 37.64% respectively.

Journal ArticleDOI
TL;DR: In this article, the experimental results of the prototype parabolic trough made of fiberglass-reinforced plastic with its aperture area coated by aluminum foil with a reflectivity of 0.86 have been described.
Abstract: Solar collector and concentrator system can be used for industrial process heat application in various industries. Apart from the low temperature applications, there are several potential fields of application for solar thermal energy at medium-high temperatures (80°C to 300°C). This paper describes the experimental results of the prototype parabolic trough made of fiberglass-reinforced plastic with its aperture area coated by aluminum foil with a reflectivity of 0.86. From Indian conditions, there is a large potential available for low-cost solar-concentrating technologies for domestic as well as industrial process heat applications. This line-focusing parabolic trough with mild steel receiver coated with black proxy material has been tested with and without glass cover. Instantaneous efficiency of 51% and 39% has been achieved with and without glass cover, respectively. Performance evaluation of the prototype system has been done during the months of April and May 2010 at Shivaji University, Kolhapur (16.42°N latitude, 74.13°W longitude). The total cost of the prototype system developed has been calculated as Rs10,000 (US$200).

Journal ArticleDOI
TL;DR: In this paper, the link between electricity consumption and mean monthly maximum temperature index in Pakistan, as a case study, is deduced and a linear trend model for electricity consumption is also developed as a function of temperature.
Abstract: Nowadays, different sectors of the economy are being significantly affected by the weather vagaries. Electricity market is one of the most sensitive sectors, due to the fact that electricity demand is connected to the numerous climatic variables, especially the atmospheric temperature. In this paper we have deduced the link between electricity consumption and mean monthly maximum temperature index in Pakistan, as a case study. ARIMA time series forecast model is developed for the temperature index. The forecast values of mean monthly maximum temperature shows an increasing trend. Linear trend model for electricity consumption is also developed as a function of temperature. Electricity consumption reveals a significant trend due to increase in temperature and socio- economic factors. The monthly behavior of our forecast values depicts that the electricity consumption is more for summer season, and this demand will be highest (6785.6 GWh) in July 2020, due to rise in temperature. Forecast model reveals that the electricity consumption (EC) and mean monthly maximum temperature are increasing with the passage of time.

Journal ArticleDOI
TL;DR: In this article, the authors present a thermodynamic investigation and environmental consideration of combined Stirling-organic Rankine cycle (ORC) power cycle, which is assisted by solar energy and an ORC used as an annular cold-side heat rejector for a free piston Stirling cycle.
Abstract: This paper presents thermodynamic investigation and environmental consideration of combined Stirling-organic Rankine cycle (ORC) power cycle. Combined cycle can be assisted by solar energy and an ORC used as an annular cold-side heat rejector for a free piston Stirling cycle. ORC can increase the power output efficiency by 4% to 8% compared to that of a Stirling standard cycle. Operating temperatures of ORC are between 80°C and 140°C. The main objective of this work is to model the combined cycle for performance optimization in respect to the use of several different working fluids with relevant temperature ranges. Total power efficiency in the range of 34% to 42% was observed for different cases. Several working fluids in the ORC were investigated from a thermal, operational, and environmental point of view. Working fluids considered were FC72, FC87, HFE7100, HFE7000, Novec649, npentane, n-decane, R245fa, and toluene. Practical issues like thermodynamic cycle efficiency, latent heat, density, toxicity, flammability, ozone depletion potential, global warming potential, and atmospheric lifetime are considered. Considering the cycle efficiency, n-decane shows the best performance at both levels of temperature supposed. However, this fluid has the highest saturated vapor specific volume (resulting in a larger condenser) and the lowest condenser saturation pressure (higher infiltration of non-condensable gases). The best candidates for the cycle regarding all the considered aspects were found to be toluene, HFE7100, and n-pentane. Comparing these three fluids, toluene presents the highest efficiency, the highest impact on the environment, the biggest vapor specific volume, and the minimum mass flow rate in Rankine cycle, therefore decreasing the pump power consumption. N-pentane exhibits the lowest cycle efficiency and vapor specific volume, but this fluid has super-atmospheric saturation pressure advantage. HFE7100 is a good working fluid from environmental and safety point of view.

Journal ArticleDOI
TL;DR: This study analyzes the effect of light supply (one of the most important culture parameters) on lipid production of selected microalgae, Chlorella vulgaris and Pseudokirchneriella subcapitata to find out whether microalgal light saturation point may be achieved.
Abstract: Background: The depletion of fossil fuel reserves has stimulated the search for sustainable sources of energy that are carbon-neutral or renewable. In this context, microalgae are a promising energetic resource. They are photosynthetic microorganisms that use CO2 as carbon source, with high specific growth rates. Furthermore, some species present high lipid content that can be easily converted into biodiesel. Accordingly, this study aims to analyze the effect of light supply (one of the most important culture parameters) on lipid production of selected microalgae, Chlorella vulgaris and Pseudokirchneriella subcapitata. Methods: Both microalgal species were cultured under different light irradiance values (36, 72, 96, and 126 μ Em �2 s �1 ) and for each light irradiance value, three light/dark ratios (10:14, 14:10, and 24:0) were tested. Lipid contents of both microalgae were then determined using a recently developed colorimetric method.

Journal ArticleDOI
TL;DR: In this article, the authors reported the findings of densifying ground maize cobs and Ceiba pentandra sawdust at room temperature using low compacting pressure without a binder.
Abstract: This paper reports the findings of densifying ground maize cobs and Ceiba pentandra sawdust at room temperature using low compacting pressure without a binder. The maize cobs were crushed using a hammer mill. Particle sizes of maize cobs and C. pentandra used for the study were ≤1 mm. The two materials were combined at mixing percentages of 90:10, 70:30 and 50:50 (C. pentandra/maize cobs). Briquettes were produced using a laboratory hydraulic press. Compacting pressure was varied from 20 to 50 MPa at an interval of 10 MPa. The results indicated that the relaxed density of briquettes produced from particles of maize cobs only ranged from 541 to 659 kg/m 3 whilst that made from a mixture of maize cobs and C. pentandra ranged from 565 to 774 kg/m 3 . Compressive strength in cleft of briquettes produced from maize cobs only ranged from 0.12 to 0.54 N/mm whilst that produced from a combination of maize cobs and C. pentandra ranged from 7.72 to 59.22 N/mm. Additionally, at all compacting pressure levels, briquettes made from maize cobs only had an impact resistance index of 0%. Whilst those made from a combination of maize cobs and C. pentandra ranged from 115% to 500%. Thus, briquettes with adequate physical and mechanical characteristics could be produced from maize cobs at room temperature using low compacting pressure when maize cobs are combined with sawdust of C. pentandra. These findings could enhance the existing technology for densifying agricultural residues, for example, maize cobs, especially in rural communities.

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TL;DR: In this paper, a semiclathrate hydrate system of carbon dioxide in tetra-n-butylammonium bromide (TBAB) with a small amount of surfactant, sodium dodecyl sulfate (SDS), for 5, 10, and 20 wt.% TBAB to determine the phase equilibrium temperature and pressure conditions.
Abstract: Experimental studies are carried out on a semiclathrate hydrate system of carbon dioxide in tetra-n-butylammonium bromide (TBAB) with a small amount of surfactant, sodium dodecyl sulfate (SDS), for 5, 10, and 20 wt.% TBAB to determine the phase equilibrium temperature and pressure conditions. It is observed that the presence of SDS did not influence the equilibrium conditions of the semiclathrate hydrate. Re-nucleation (memory) effect of semiclathrate hydrates of CO2 is studied for few cases of TBAB concentration in an aqueous solution. The equilibrium pressure and temperature conditions obtained for memory effect and regular experimental run without memory effect were observed to be quite close. It is concluded that in the case of no memory effect, with increasing TBAB percentage in the system, the time required for nucleation is reduced. For the same TBAB concentration, the incipient pressure and temperature required for nucleation and re-nucleation of semiclathrate hydrates increase while the time required for re-nucleation decreases.

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TL;DR: In this article, the effect of temperature and ambient condition on Jatropha biodiesel storage was investigated for a period of 12 months, where the samples were taken out to analyze acid value, density, kinematic viscosity, and thermogravimetric profile to monitor the quality of biodiesel.
Abstract: Jatropha curcas L. seeds as a raw material for biodiesel production is a rapidly growing interest over the world because of its high oil content, ecological adaptability, and excellent fuel properties. Though there is an increase in productivity of biodiesel, showing solution for future energy insecurity, there still remains some concern for commercialization due to its susceptibility to degradation during long storage. The aim of this paper is to investigate the effect of temperature and ambient condition on Jatropha biodiesel storage. An experiment was conducted for a period of 12 months, where Jatropha biodiesel stored in three groups at different temperatures (4°C, 25°C, and 35°C) and environmental conditions (exposed in dark, light, and air). At regular intervals, the samples were taken out to analyze acid value, density, kinematic viscosity, and thermogravimetric profile to monitor the quality of biodiesel. Analysis showed that acid value, density, kinematic viscosity, and the onset temperature of volatilization and distillation increases with the increase in storage time of biodiesel samples. However, Jatropha biodiesel stored at 35°C, in contact with ambient air and light showed highest degradation compared to those which were stored at 25°C and 4°C. Among all the parameters studied, high temperature and air exposure are the two most potent parameters which accelerate the degradation process. Along with that, light exposure had mild but significant effect on Jatropha biodiesel degradation over a long storage period.


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TL;DR: In this paper, a modified ecological function is presented for four-temperature-level absorption refrigerators, and an absorption refrigerator has been optimized using this function An equivalent system was initially identified, followed by the application of the first and second laws of thermodynamics Next, the optimization results were interpreted.
Abstract: In this study, a modified ecological function is presented for four-temperature-level absorption refrigerators, and an absorption refrigerator has been optimized using this function An equivalent system was initially identified, followed by the application of the first and second laws of thermodynamics Next, the optimization results were interpreted The results of the optimization process, optimum point of xH, xR, aH, and aR, were defined as 087, 058, 241, 025, respectively In addition to that, the effects of xH, xR, aH, aR, Ta, Tc, Te, and Tg were shown according to exergy destruction, ecological function, coefficient of performance, and cooling load As a result, it was understood that especially the xH, parameter, and the generator temperatures are the variables of the system that require special attention because, at some points, they cause that generator and absorber transfer heat in the opposite direction they need to do

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TL;DR: In this article, the dependence of the impedance spectrum on the state of charge and the carbon content was explored by exploring the origin of this discrepancy by studying the dependence on impedance spectrum and carbon content.
Abstract: Recently, there exists a discrepancy on the lithium ion de-intercalation mechanism for LiCoPO4 electrode. In the present work, the study was focused upon exploring the origin of this discrepancy by studying the dependence of the impedance spectrum on the state of charge and the carbon content. For the pure LiCoPO4 electrode, the two plateaus in the charge curve are at 4.82 and 4.92 V. We have also studied the variation of electrochemical impedance spectroscopies (EISs) with the state of charge. The EIS measurement has shown that the total interfacial resistance increases as the state of charge increases for the pure LiCoPO4 electrode. If higher content of sucrose was added in the precursor (this implies higher carbon content in the synthesized sample), only one potential plateau can be found in the charge curve. For this electrode, the total interfacial resistance decreases with the state of charge. Especially, the total interfacial resistance has a dramatic decrease when the state of charge increases from 20% to 40%. It is believed that the influence of carbon impurity on the variation tendency of the EIS pattern may reflect the change of the fine structure. For the pure LiCoPO4 electrode, the intermediate phase is Li0.20~0.45CoPO4.