INTERNATIONAL JOURNAL OF ENERGY AND ENVIRONMENTAL ENGINEERING
Year:2013 | Volume:4 | Issue:4|Papers Count:12

An integrated and sustainable fermentation process was developed which enabled both the revalorization of two regional agro-industrial discards as well as by-product reuse. Carrot and brewer's yeast, which are commonly used for animal feed, were processed to obtain 77.5 L of ethanol, 450 kg of solid waste called bagasse, 970 L of liquid effluent called vinasse, and 39.8 kg CO2 per each ton of discarded carrot. Results showed that the obtained bagasse was suitable for feeding 55 animals (calfs). The dilution of vinasse with fresh water (1: 5) satisfied the requirements necessary to be used as beverage for the same number of animals, leaving a remnant which could be newly diluted (1: 5) and used to irrigate a 0.025-ha carrot crop, the land dimension required to grow 1 ton of carrot.

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 modeling 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.

Palm oil mills are generally self-sufficient in terms of energy. However, burning of biomass fuel in a boiler has generated serious air pollution problem due to inappropriate boiler operation and inefficient dust collection system. This study aims to simulate the total dust emission from palm oil mills in Malaysia by modeling biomass fuel composition and dust collector efficiency. It has been found that before removal, the simulated average dust load after biomass boiler was 51.67±5.39 g/s at a confidence level of 95%, and total dust load was 389, 961 tonnes/year. Simulation values of total dust emission at different percentages of dust collector efficiency at 60%, 70%, 80%, 90% and 95% were 155, 984, 116, 988, 77, 992, 38, 996 and 19, 498 tonnes/year, respectively. The simulation has also shown that dust concentration at a boiler outlet was 4.5 g/Nm3. From the study, dust removal efficiency should be above 91% to ensure the compliance of dust concentration at 0.4 g/Nm3 as prescribed by the Environment Quality (Clean Air) Regulations of 1978. Whereas in 2009, Sabah state has processed the most quantities of fresh fruit bunches; it has posed a potential impact on the environment and public in terms of total dust emission. Besides stack sampling that is used to monitor dust emission status, simulation can be a more simple way and an alternative to estimate the emission.

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.

LiCoPO4 has been recognized as a promising cathode material for lithium batteries due to its high stability and high operation voltage. However, poor electronic conductivity of LiCoPO4 prohibits its practical use. A carbon coating can improve electronic conductivity of LiCoPO4. A hydrothermal synthesis is a very convenient method because it allows us easy preparation of small particles of carbon-coated LiCoPO4; however, an effect of precursor for LiCoPO4 preparation on the performance of the synthesized LiCoPO4 has yet to be cleared. In this paper, the effect of Co source for carbon-coated LiCoPO4 (LiCoPO4/C) preparation on performance as a cathode material for Li-ion battery is investigated. The Co source strongly affects the pH value in the starting solution and final products.The single-phase LiCoPO4 is obtained only when CoSO4 or CoCl2 are used as the Co sources. A quality of carbon layer on the LiCoPO4 is also affected by the Co source. The carbon layer on the LiCoPO4 synthesized from CoSO4 contains graphite carbon with high concentration which provides high electronic conductivity compared with that from CoCl2. Accordingly, the LiCoPO4/C synthesized from CoSO4 shows a superior performance than that from CoCl2 due to high-quality carbon layer.

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 Li0.20~0.45 CoPO4.

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 (4oC, 25oC, and 35oC) 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 thermo gravimetric 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 35oC, in contact with ambient air and light showed highest degradation compared to those which were stored at 25oC and 4oC. 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.

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 modeling biological growth system. The objective of this study is to estimate PAR for latitudes ranging from 9o to 34o 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 9o latitude, PAR=0.040 (Hg)0.924, R2=0.970, (b) 14o latitude, PAR=0.029 (Hg)0.952, R2=0.894, (c) 19o latitude, PAR=0.256 (Hg)0.748, R2=0.721, (d) 24o latitude, PAR=0.159 (Hg)0.775, R2=0.896, (e) 29o latitude, PAR=0.052 (Hg)0.886, R2=0.830 and (f) 34o latitude, PAR=0.016 (Hg)1.013, R2=0.768.

The quantities of common emissions are investigated for a specific type of commercial aircraft. Actual flight data and International Civil Aviation Organization emission data are used. All flight phases are considered, including landing and takeoff phases. The investigation is carried out for the domestic flights only and considers relevant parameters, such as engine type, flight phase, and ground or air operation of the flight. The findings suggest that the quantities of emissions of unburned hydrocarbon (HC) and carbon monoxide (CO) during the descent phase can exceed those for the taxi phases and the idle operation of the engines, depending on the approach procedure.The main source of nitrogen oxide (NOx) is usually the climb phase, while the mean total flight emissions are calculated as 6 to 8 kg of HC, 60 to 75 kg of CO, and 28 to 31 kg of NOx. The effect of the duration of taxi phase on the production of HC and CO emissions is also discussed.

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 thatin silico metabolic modeling 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 modeling 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.

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 69.2oC when it was studied under no-load conditions. The maximum air temperature in the dryer, under this condition, was 64.1oC. 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 m2. This solar dryer been be used in experimental drying tests under various loading conditions.

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 mE m-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.Results/Conclusions: P. subcapitata presented higher lipid productivity than C. vulgaris. High lipid concentration was achieved in microalgal cultures with higher light irradiance values. However, for 96 and 126 mE m-2 s-1, lipid productions of both microalgae were not significantly higher than with 72 mE m-2 s-1, which means that microalgal light saturation point may be achieved.