Good Source Of Renewable Energy Research Articles

Estimation of leaf nitrogen levels in sugarcane using hyperspectral models

ABSTRACT: Sugarcane is a good source of renewable energy and helps reduce the emission of greenhouse gases. Nitrogen has a critical role in plant growth; therefore,estimating nitrogen levels is essential, and remote sensing can improve fertilizer management. This field study selects wavelengths from hyperspectral data on a sugarcane canopy to generate models for estimating leaf nitrogen concentrations. The study was carried out in the municipalities of Piracicaba, Jaú, and Santa Maria da Serra, state of São Paulo, in the 2013/2014 growing season. The experiments were carried out using a completely randomized block design with split plots (three sugarcane varieties per plot [variety SP 81-3250 was common to all plots] and four nitrogen concentrations [0, 50, 100, and 150 kgha-1] per subplot) and four repetitions. The wavelengths that best correlated with leaf nitrogen were selected usingsparse partial least square regression. The wavelength regionswere combinedby stepwise multiple linear regression. Spectral bands in the visible (700-705 nm), red-edge (710-720 nm), near-infrared (725, 925, 955, and 980 nm), and short-wave infrared (1355, 1420, 1595, 1600, 1605, and 1610 nm) regions were identified. The R² and RMSE of the model were 0.50 and 1.67 g.kg-1, respectively. The adjusted R² and RMSE of the models for Piracicaba, Jaú, and Santa Maria were 0.31 (unreliable) and 1.30 g.kg-1, 0.53 and 1.96 g.kg-1, and 0.54 and 1.46 g.kg-1, respectively. Our results showed that canopy hyperspectral reflectance can estimate leaf nitrogen concentrations and manage nitrogen application in sugarcane.

Kinetic study and optimization of total solids for anaerobic digestion of kitchen waste: Bangladesh perspective.

Kitchen waste from hotels and homes is one of the major problems for urban and rural environment and could be one of the best sources of renewable energy by producing biogas through anaerobic digestion. A research work was undertaken to assess the methane potential of kitchen waste at different total solids (TS) content. Kitchen wastes such as spoiled rice, brinjal, potato, papaya, tomato, fish and poultry parts etc., which are easily decomposed, were selected for this study. Batch experiments were set up under ambient temperature. Kitchen waste was added to the batch digester at different TS content (5, 7, 10, 12 and 15%) and sealed for 146 days until the gas production stopped. Substrate characteristics were analyzed before and after the anaerobic digestion. The highest methane yield was 78.12 L/kg VS at 15% TS content followed by 12, 10, 7 and 5%. Different kinetic parameters were determined using a logistic model and the model showed a good fit with the experimental results. After modelling using Minitab®, the optimum TS content for kitchen waste was found to be 14.90%.

Effects of heat transfer based water for three square multilayer absorber solar collector

Solar energy is one of the best sources of renewable energy with minimal environmental impact. In this study, the effect of absorber solar collector on the performance of the solar water heating system has been experimentally investigated. This study is aimed to obtain the output of temperature for absorber solar collector based on water moving to the system. In the solar water heating system, volume flow rate with 2, 3 and 4 liters per minute for each solar radiation for 300, 500 and 700 W/m2 respectively. The result indicates at higher temperature output at 700 W/m2 of solar radiation within 30 minutes during charging and discharging process at volume flow rate 4 l/m is 36.9 °C. A little bit difference for 300 and 500 W/m2 which are 36 °C and 36.6 °C respectively. Solar water heating systems, in difference collectors have long distance, have temperature increases based on water medium in the system. Heat transfer performance with different radiation intensities of 300, 500 and 700 W/m2. The heat transfer performance for radiation of 700 W/m2 shows the highest followed by 500 W/m2. The lowest heat transfer performance is seen at 300 W/m2.

Numerical modeling of Maranhão Gulf tidal circulation and power density distribution

Marine resources are outstanding among renewable energy for their wide occurrence and diverse possibilities of exploitation. The tidal resource can be harnessed by the use of both potential (sea level) and kinetic energy (tidal currents). Maranhao coast presents one of the largest tidal ranges and strongest currents on Brazilian coastline, providing a good source of renewable energy. A 3D hydrodynamic model is implemented to numerically simulate the tidal circulation in the Maranhao Gulf so as to examine the tidal behavior and associated energy distribution. Amplitudes and current speeds are substantially increased by the estuary’s geomorphology and the shallow bathymetry. M2 tidal component presents the highest amplitudes among the tidal constituents, being the most energetic. Spring-neap cycle constitute an important factor in energy assessment due to their significant difference in power density and exchanged water volume between estuary and continental shelf. Maximum current velocities of 3 m s−1 are found around Medo Island, where tidal range can reach nearly 5.5 m. Three potential regions are located within the Sao Marcos Estuarine Complex, presenting surface velocities ranging from 1 to 2.15 m s−1 and power density as high as 5 kW m−2. The estuary is long and presents significant variations of tidal phase that allows a geographical disposition of turbines in order to lower the downtime.

Rice Straw Biomass to High Energy Yield Biocoal by Torrefaction:Indian Perspective

India is an agriculture based country and generates more than 600 million tonnes of biomass waste from different crops and produces 140 million tonnes of rice straw alone annually. To dispose the rice straw for making field ready for next crop, farmers are burning it in the fields. Burning of rice straw in agriculture fields poses lot of environmental, health and economic issues in various parts of the country. On one hand, rice straw is a good source of renewable energy but on the other hand it has some inherent problems. Therefore, to mitigate problems due to the burning of rice straw, in this study, an effort is made to convert rice straw into an useful product by torrefaction process, i.e. biocoal. The biocoal which has the calorific value equivalent to that of bituminous coal is used in thermal power plants. By optimizing the processing parameters of torrefaction process, desired calorific value of torrefied product has been archived. The 10% use of torrefied product with coal can consume 140 million tonnes of rice straw and as a consequence, it reduces the consumption of fossil fuels. This can greatly solve problems arising due to burning of rice straw and reduce greenhouse gas emission significantly.

Fully coupled wellbore-reservoir simulation of supercritical CO2 injection from fossil fuel power plant for heat mining from geothermal reservoirs

Abstract The concept of injecting supercritical CO2 (sCO2) into a geothermal reservoir was computationally investigated to assess its performance in terms of the benefit of using CO2 captured from fossil power plants for geothermal heat mining. A coupled wellbore-reservoir system was simulated considering the flow of pure sCO2 in an injection well, the interaction of sCO2 and water in a permeable reservoir, and the flow of the two-phase mixture of sCO2 and water in a production well. Results of simulations indicate that this CO2 application is capable of providing a good source of renewable energy. It was found that for a reservoir with a 0.08 km3 volume, about 8–9 MWth could be extracted in a steady state fashion for a 30-year lifetime operation. This is approximately equivalent to 100 MWth/km3. A sensitivity analysis provided information on the impact of certain parameters on the performance of the integrated system. The injection flowrate, the distance between the production and injection wellbores and the penetrating depth of the production wellbore into the reservoir have a first order impact on the pressure management of the reservoir. Additionally, CO2 injection temperature has a large effect on the thermosiphon characteristics of the system.

Composition of Domestic Solid Waste on Biogas Production and Characteristic in MSW Landfill

Organic solid waste will undergo a decomposition process and produces some gases compounds such as a large enough of Methane (CH4), Carbon Dioxide (CO2) with Oxygen (O2) and N2. The high heating value of CH4 in biogas can make biogas as a good source of renewable energy and environmentally friendly. Biogas calorie efficiency is proportional to the concentration of CH4 in biogas. However, the quantity and quality of biogas that produced in landfill depend on the characteristic and density of domestic solid waste in landfill. The composition of organic and inorganic waste and the density of waste pile will alter the CH4 content. This study focuses on measuring CH4 content of the solid waste with different density while also identifying the composition of disposed solid waste. The result indicates that the CH4 content ranges from 33% to 57.7% with 22.19% to 42.24% of CO2 and approximately 1.21% - 7.92% of O2. The presence of inorganic waste and density level of waste contribute to the decomposition rate and CH4 content.

Pyrolysis of Napier Grass in a Fixed Bed Reactor: Effect of Operating Conditions on Product Yields and Characteristics

This study presents a report on pyrolysis of Napier grass stem in a fixed bed reactor. The effects of nitrogen flow (20 to 60 mL/min), and reaction temperature (450 to 650 °C) were investigated. Increasing the nitrogen flow from 20 to 30 mL/min increased the bio-oil yield and decreased both bio-char and non-condensable gas. 30 mL/min nitrogen flow resulted in optimum bio-oil yield and was used in the subsequent experiments. Reaction temperatures between 450 and 600 °C increased the bio-oil yield, with maximum yield of 32.26 wt% at 600 oC and a decrease in the corresponding bio-char and non-condensable gas. At 650 °C, reductions in the bio-oil and bio-char yields were recorded while the non-condensable gas increased. Water content of the bio-oil decreased with increasing reaction temperature, while density and viscosity increased. The observed pH and higher heating values were between 2.43 to 2.97, and 25.25 to 28.88 MJ/kg, respectively. GC-MS analysis revealed that the oil was made up of highly oxygenated compounds and requires upgrading. The bio-char and non-condensable gas were characterized, and the effect of reaction temperature on the properties was evaluated. Napier grass represents a good source of renewable energy when all pyrolysis products are efficiently utilized.

Pyrolysis of Oil Palm Residues in a Fixed Bed Tubular Reactor

Searching for alternative energy sources continues to grow in recent times due to the fear of energy insecurity in the near future and environmental and sociopolitical issues associated with the use of fossil fuel. Among the renewable energy sources, biomass is the only source that has carbon in its building blocks which can be processed to liquid fuel. In this study, pyrolysis of oil palm residues (trunk, frond and empty fruit bunch) was carried out in a fixed bed tubular reactor under nitrogen atmosphere at 30 mL/min, 30?C/min heating rate and 600?C reaction temperature. Pyrolysis products (bio-oil, bio-char and non-condensable gas) were characterized. Water content, acidity (pH), higher heating value (HHV) and oxygen content of the bio-oil varied between 39.28 - 43 wt%, 2.92 - 3.20, 19.29 - 21.92 MJ/kg and 58.47 - 59.85 wt% respectively. Low pH, highwater and oxygen contents in the oil make it unsuitable for being used as fuel and therefore require upgrading. Scanning electron microscopy and ultimate analysis of the bio-char suggests that it is a porous material and consists mainly carbon between 82.22 - 84.96 wt% and has HHV in the range of 25.98 - 27.65 MJ/kg. This may be used as solid biofuel, adsorbent and source of carbon. High percentage of hydrogen (H2) and carbon monoxide (CO) were observed in the non-condensable gas which may be processed to transportation fuel via Fisher-Tropsch process. Oil palm residues represent good source of renewable energy when all the pyrolysis products are efficiently utilized.

Abattoir by-Product Utilization for Sustainable Meat Industry: A Review

Meat sector in India plays an important role in providing livelihood to rural people in the country. Animal slaughtering not only provides meat but also valuable byproducts to the mankind. By slaughtering and processing of meat animal, only one third is meat while the rest comprise of byproducts and waste, which need to be adequately processed and utilized. Traditional markets for edible meat by-products have gradually been disappearing because of concerns about health and economic returns. In response to these problems, meat processors have directed marketing and research efforts toward inedible applications. Efficient utilization of byproducts has direct impact on the economy and environmental pollution of the country, the former being an asset and the latter is a responsibility. The yield of animal by-products ranges between 50-60% of the live weight. According to various statistics 107 million livestock and more than 650 million poultry birds were slaughtered annually in India leading to production of 6.3 million tonnes meat. It leaves huge loads of byproducts. The load is further increased by dead and fallen animals. The value of unprocessed by-products from buffalo and sheep in India was reported to be quite high. If these by-products are processed then the returns will be almost equal to the value of the meat derived from an animal. Therefore, the potential and scope of by-product utilization is really great which will result in industrial development, employment generation, environmental management and better returns to the farmers. Non-utilization of animal by-products in a proper way may create major aesthetic and catastrophic health problems. Value addition of animal byproducts has two benefits. Firstly, the meat industry gets additional revenue by processing them to industrial, household, and cosmetic products; livestock feed additives; pet foods; pharmaceutical and medical supplies etc that otherwise would have been unrealized. Secondly, the costs of disposing of these secondary items are avoided. Utilization of these byproducts as fertilizer contributes a lot in organic farming and could reduce our dependence on synthetic fertilizers. Animal byproducts and wastes are a good source of renewable energy as well its production is economically feasible.

Similarity solution to three dimensional boundary layer flow of second grade nanofluid past a stretching surface with thermal radiation and heat source/sink

Development of human society greatly depends upon solar energy. Heat, electricity and water from nature can be obtained through solar power. Sustainable energy generation at present is a critical issue in human society development. Solar energy is regarded one of the best sources of renewable energy. Hence the purpose of present study is to construct a model for radiative effects in three-dimensional of nanofluid. Flow of second grade fluid by an exponentially stretching surface is considered. Thermophoresis and Brownian motion effects are taken into account in presence of heat source/sink and chemical reaction. Results are derived for the dimensionless velocities, temperature and concentration. Graphs are plotted to examine the impacts of physical parameters on the temperature and concentration. Numerical computations are presented to examine the values of skin-friction coefficients, Nusselt and Sherwood numbers. It is observed that the values of skin-friction coefficients are more for larger values of second grade parameter. Moreover the radiative effects on the temperature and concentration are quite reverse.

An Overview of Energy Sector and Wind Power Potential in Malaysia

With the new era of industrialization and urbanization, the use of renewable energy is a solution to resolve the impacts of the current dependency on fossil based fuels and hike in fuel prices in the world. The rapid economic development in recent years has led to the energy increase demand in Malaysia and the situation is expected to grow in the near future. The country energy sector is heavily dependent on fossil based fuels for electrical energy generation. Currently, wind energy systems are swiftly gaining recognition as one of the best sources of renewable energy because of its emission free characteristics. This paper reviews the recent scenario and the future expected energy situation in Malaysia. Wind energy resources assessment and potential in Malaysia is also discussed.

Heat transfer and entropy generation through nanofluid filled direct absorption solar collector

Sustainable energy generation is one of the most important challenges facing society today. Solar energy is one of the best sources of renewable energy with minimal environmental impact which offers a solution. The present work investigates the heat transfer performance and entropy generation of forced convection through a direct absorption solar collector. The working fluid is Cu–water nanofluid. The simulations focus specifically on the effect of solid volume fraction of nanoparticle and Reynolds number on the mean Nusselt number, mean entropy generation, Bejan number and collector efficiency. Also Isotherms and heatfunction are presented for various solid volume fraction and inertia force. The governing partial differential equations are solved using penalty finite element method with Galerkins weighted residual technique. The results show that both the mean Nusselt number and entropy generation increase as the volume fraction of Cu nanoparticles and Reynolds number increase. The results presented in this study provide a useful source of reference for enhancing the forced convection heat transfer performance while simultaneously reducing the entropy generation.

Microalgae as a Renewable Source of Energy: A Niche Opportunity

Algae are believed to be a good source of renewable energy because of its rapid growth rate and its ability to be cultivated in waste water or waste land. Several companies and government agencies are making efforts to reduce capital cost and operating costs and make algae fuel production commercially viable. Algae are the fastest growing plant and theoretically have the potential to produce more oil or biomass per acre when compared to other crops and plants. However, the energy efficiency ratio and carbon and water footprint for algal based biofuels still need to be evaluated in order to fully understand the environmental impact of algal derived biofuels.

Effects of physical parameters on natural convection in a solar collector filled with nanofluid

AbstractSolar energy is one of the best sources of renewable energy with minimal environmental impact. A numerical study has been conducted to investigate the natural convection inside a solar collector having a flat‐plate cover and a sine‐wave absorber. The water‐alumina nanofluid is used as the working fluid inside the solar collector. The governing differential equations with boundary conditions are solved by the penalty finite element method using Galerkin's weighted residual scheme. The effects of physical parameters on the natural convection heat transfer are simulated. These parameters include the number of wave λ and non‐dimensional amplitude A of the sinusoidal corrugated absorber. Comprehensive average Nusselt number, average temperature, and mean velocity field for both nanofluid and base fluid within the collector are presented as functions of the parameters mentioned above. Comparison with previously published work is made and found to be in excellent agreement. The numerical results show that the highest heat transfer rate is observed for both the largest λ and A. In addition, the design for enhancing the performance of the collector is determined by examining the above‐mentioned results. © 2012 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.21026

Feasibility Study for Production of Biofuel and Chemicals from Marine Microalgae Nannochloropsis sp. Based on Basic Mass and Energy Analysis

Algae are believed to be a good source of renewable energy because of their rapid growth rate and their ability to be cultivated in waste waters or waste land. The algae Nannochloropsis sp. was chosen for this study, where lipids were extracted and transesterified for biodiesel production. The FFA (free fatty acid) content in the lipid was estimated to be 27 wt% of the total fatty acids. The remaining biomass after lipid extraction was pyrolyzed at 200°C, 300°C, and 400°C to produce solid, liquid, and gas products. The GC/MS showed that the lipids of Nannochloropsis sp. consist of high concentration of polyunsaturated fatty acids (29 wt%), eicosapentaenoic acid. The bio-oil produced from pyrolysis of algae biomass (after lipid extraction) at 300°C was composed of 50 wt% acetone, 30 wt% methyl ethyl ketone and 19 wt% aromatics such as pyrazine and pyrrole. The heating value of bio-oil is 32 MJ/kg of oil.

Sweet Sorghum as Feedstock for Biofuel Production: A Review

Fossil energy resources, the primary source of transport fuel in the world is depleting dramatically to meet the ever-increasing energy demands globally. Crop plants are one of the best sources of renewable energy which can be used as feedstock for biofuel production. Sweet sorghum [Sorghum bicolor (L.) Moench], a C4 Graminaceous crop which has sugar-rich stalks and which is a water-use efficient crop has a very good potential as an alternative feed stock for ethanol production. It is the only crop that provides grain and stem that can be used for sugar, alcohol, syrup, jaggery, fodder, fuel, bedding, roofing, fencing, paper and chewing. Sweet sorghum juices usually contain approximately 16–18% fermentable sugar, which can be directly fermented into ethanol by yeast. Technical challenges of using sweet sorghum for biofuels are a short harvest period for highest sugar content and fast sugar degradation during storage. Various review works based on the problems of sweet sorghum were described in this review. Some studies are on the genetic potential of sweet sorghum for higher green cane yield and juice extractability where as some studies are purely on the shelf life of the juice how to preserve the juice with low cost against bacterial contamination. Studies also involve testing the potential of genotypes for superior yields of cane during post rainy and summer seasons also to make the cane available for maximum period in a year. Studies on fermentation and hydrolysis of lignocellulose are also addressed in this review.

Nanofluid-based direct absorption solar collector

Solar energy is one of the best sources of renewable energy with minimal environmental impact. Direct absorption solar collectors have been proposed for a variety of applications such as water heating; however the efficiency of these collectors is limited by the absorption properties of the working fluid, which is very poor for typical fluids used in solar collectors. It has been shown that mixing nanoparticles in a liquid (nanofluid) has a dramatic effect on the liquid thermophysical properties such as thermal conductivity. Nanoparticles also offer the potential of improving the radiative properties of liquids, leading to an increase in the efficiency of direct absorption solar collectors. Here we report on the experimental results on solar collectors based on nanofluids made from a variety of nanoparticles (carbon nanotubes, graphite, and silver). We demonstrate efficiency improvements of up to 5% in solar thermal collectors by utilizing nanofluids as the absorption mechanism. In addition the experimental data were compared with a numerical model of a solar collector with direct absorption nanofluids. The experimental and numerical results demonstrate an initial rapid increase in efficiency with volume fraction, followed by a leveling off in efficiency as volume fraction continues to increase.