New Renewable Energy Sources Research Articles

Enhancement of Energy Harvesting Performance by a Coupled Bluff Splitter Body and PVEH Plate through Vortex Induced Vibration near Resonance

Inspired by vortex induced vibration energy harvesting development as a new source of renewable energy, a T-shaped design vibration energy harvester is introduced with the aim of enhancing its performance through vortex induced vibration at near resonance conditions. The T-shaped structural model designed consists of a fixed boundary aluminum bluff splitter body coupled with a cantilever piezoelectric vibration energy harvesters (PVEH) plate model which is a piezoelectric bimorph plate made of a brass plate sandwiched between 2 lead zirconate titanate (PZT) plates. A 3-dimensional Fluid-Structure Interaction simulation analysis is carried out with Reynolds Stress Turbulence Model under wind speed of 7, 10, 12, 14, 16, 18, 19, 20, 22.5, and 25 m/s. The results showed that with 19 m/s wind speed, the model generates 75.758 Hz of vortex frequency near to the structural model’s natural frequency of 76.9 Hz. Resonance lock-in therefore occurred, generating a maximum displacement amplitude of 2.09 mm or a 49.76% increment relatively in vibrational amplitude. Under the effect of resonance at the PVEH plate’s fundamental natural frequency, it is able to generate the largest normalized power of 13.44 mW/cm3g2.

Global Reaction Model to Describe the Kinetics of Catalytic Pyrolysis of Coffee Grounds Waste

In view of the constant search for new sources of renewable energy, the particulate agro-industrial waste reuse emerges as an advantageous alternative. However, despite the advantages of using the biomass as an energy source, there is still strong resistance as the large-scale replacement of petroleum products due to the lack of scientifically proven efficient conversion technologies. In this context, the pyrolysis is presented as one of the most widely used thermal decomposition processes. The knowledge of aspects of chemical kinetics, thermodynamics these will, heat and mass transfer, are so important, since influence the quality of the product. This paper presents a kinetic study of slow pyrolysis of coffee grounds waste from dynamic thermogravimetric experiments (TG), using different powder catalysts. The primary thermal decomposition was described by the one-step reaction model, which considers a single global reaction. The kinetic parameters were estimated using nonlinear regression and the differential evolution method. The coffee ground waste was dried at 105°C for 24 hours. The sample in nature was analyzed at different heating rates, being 10, 15, 20, 30 and 50 K/min. In the catalytic pyrolysis, about 5% (w/w) of catalyst were added to the sample, at a heating rate of 30 K/min. The results show that the one-step model does not accurately represent the data of weight loss (TG) and its derivative (DTG), but can do an estimative of the activation energy reaction, and can show the differences caused by the catalysts. Although no one can say anything about the products formed with the addition of the catalyst, it would be necessary to micro-pyrolysis analysis, we can say the influence of the catalyst in the samples, based on the data obtained in thermogravimetric tests.

Modification of Solar Energy Harvesting in Photovoltaic Materials by Plasmonic Nanospheres: New Absorption Bands in Perovskite Composite Film

Thin-film perovskite-based photovoltaics has great potential to make an important contribution to the ongoing search for new sources of clean renewable energy. Excitation of localized surface plasmons in metal nanoparticles could establish a new route for an improvement of the performance of such devices. Using the tools of electrodynamics (Lorenz–Mie theory adopted for absorbing host media), we predict a strong red shift in the spectral activity of gold and silver nanospheres and modification (negative or positive) of white and solar light harvesting in the film of perovskite host caused by centrally distributed plasmonic nanospheres. The enhancement of absorption in perovskite host is proven to be possible for photons with energies close to or smaller than the energy band gap in perovskite, with the final effect depending on the diameter of nanospheres, their concentration, and kind of metal. From the electronic band structure point of view, the predicted strengthening of absorption can be interpreted a...

APROVECHAMIENTO DEL RECURSO BIOMASA A PARTIR DE LOS DESECHOS DE MADERA PARA UNA CALDERA DE VAPOR

<p>Desde el auge del petróleo y la consecuente quema de combustibles fósiles, las emisiones de gases que provocan el efecto invernadero han aumentado. Teniendo en cuenta este punto de vista, la producción de energía renovable es necesario; por ejemplo, podemos aprovechar el potencial de la energía térmica de la biomasa residual utilizando equipos tales como una caldera de vapor, dispositivos de gran demanda en muchos procesos dentro de la industria.</p><p> </p><p>El uso de la biomasa residual, en este caso, los de residuos de madera, son de vital importancia en el medio ambiente; ya que, se trata de una contaminación neutral frente a la contaminación por hidrocarburos. Por lo tanto, la operación de una caldera de vapor con biomasa tiene como objetivo ofrecer las mismas características que un equipo convencional.</p><p> </p><p>El lector sabrá sobre: el origen de la biomasa a partir de residuos de madera, las fuentes más comerciales de la biomasa de madera, el uso final de estos desechos, y los niveles de contaminación que produce la biomasa comparables a los derivados del petróleo utilizados en la caldera. A través de pruebas experimentales de laboratorio se demuestran las propiedades físicas y energéticas que posee este recurso, con el que vamos a trabajar en los cálculos pertinentes para ser generado en la caldera de vapor.</p>

Mechanisms of Formation of Natural Hydrogen Reservoirs in Thermal Aquifers - Impact of Bacteria and Gas Bubble Dynamics

Underground hydrogen reservoirs, whose existence has been confirmed recently by geologists all over the world, represent a new source of renewable energy. Hydrogen is formed as the product of reaction of serpentinization between ferromagnesian minerals of the Mantle and water in the offshore zones of subduction or in continental zones at considerable depth beneath hydrothermal aquifers. Initially dissolved in water, hydrogen can create free gas bubbles when the local concentration of H2 dissolved in water exceeds the equilibrium value. The bubbles raise up and create the gas cap of free hydrogen. This process is significantly influenced by methanogen bacteria inhibiting in aquifers and consuming hydrogen for their metabolism. The reactions initiated by bacteria leads to the appearance of other volatile components as methane. The dimension, the form of the gas cap and the concentration of hydrogen and methane determine the efficiency of gas production and the energy potential of the reservoir. In the present paper we develop the conceptual mathematical model of gas cap formation in hydrogen reservoir. The bacterial activity is described by the equation of population dynamics with specific kinetic functions obtained by the authors by treating experimental data. The formation of free gas is modelled in terms of the formation of oversaturated nuclei, their growth and simultaneous motion of isolated bubbles. As far as the bubbles grow, they stick together and create continuous free gas. Thus, the hydrogen motion consists of two stages: (i) the motion of isolated bubbles, controlled by the equations of ganglion dynamics; and (ii) the motion of continuous gas through water, governed by Darcy’s law. The bubble growth is ensured by the mass exchange with hydrogen dissolved in water, which involves a non-equilibrium in the average hydrogen concentrations. Such a problem of hydrogen raising is solved analytically in simplified situation without bacteria. The problem can be reduced to a system of nonlinear hyperbolic equations, which has either continuous or discontinuous solutions (shock waves) depending on the degree of the non-equilibrium. Multiples deformations of the shocks under gas raising are described. The impact of bacteria is studied numerically by using the open source Basilisk (developed by D’Alembert Institute). We have revealed non trivial scenarios of the appearance of piece-wise constant traveling waves, or auto-oscillations caused by the nonlinear population dynamics. The result obtained enables us to give estimation to the characteristic time of gas cap formation and the evolution of its composition in time.

The energy of the vacuum related to the theory of energy absorption

The primary objective in this article is to investigate a new source of renewable energy, the existence of the vacuum in five environments, and the possibility of absorption of the explosion. The study has also addressed the development of new principles in the motor industry, protection against explosions, new principles of mineral processing and new types of explosives. Also, this study may offer some insight into new approaches in solving problems in thermodynamics, the development of gravity waves, the basis of renewable energy source, and the mechanism of the emergence of gravitational waves.

Energy efficiency and building environment

With the environmental protection posing as the number one global problem, man has no choice but reducing his energy consumption, one way to accomplish this is to resort to passive and low-energy systems to maintain thermal comfort in buildings. The conventional and modern designs of wind towers can successfully be used in the hot arid regions to maintain thermal comfort (with or without the use of ceiling fans) during all hours of the cooling season, or a fraction of it. Climatic design is one of the best approaches to reduce the energy cost in buildings. Proper design is the first step of defence against stress of climate. Buildings should be designed according to climate of the site for reducing the need of mechanical heating or cooling hence maximum natural energy can be used for creating pleasant environment inside the built envelope. Technology and industry progress of the last decade diffused electronic and informatics’ devices in many human activities and now appear also in building construction. The utilisation and operating opportunities components, increase the reduction of heat losses by varying the thermal insulation, optimise the lighting distribution with louver screens and operate mechanical ventilation for coolness in indoor spaces. In addiction to these parameters the intelligent envelope can act for security control and became an important part of the building demotic revolution. Application of simple passive cooling measure is effective in reducing the cooling load of buildings in hot and humid climates. 43% reductions can be achieved using a combination of well-established technologies such as glazing, shading, insulation, and natural ventilation. More advanced passive cooling techniques such as roof pond, dynamic insulation, and evaporative water jacket need to be considered more closely. The building sector is a major consumer of both energy and materials worldwide, and the consumption is increasing. Most industrialised countries are in addition becoming more and more dependent on external supplies of conventional energy carriers, i.e., fossil fuels. Energy for heating and cooling can be replaced by new renewable energy sources. New renewable energy sources, however, are usually not economically feasible compared with the traditional carriers. In order to achieve the major changes needed to alleviate the environmental impacts of the building sector, it is necessary to change and develop both the processes in the industry itself, and to build a favourable framework to overcome the present economic, regulatory and institutional barriers.

Combustion tests of grape marc in a multi-fuel domestic boiler

New sources of renewable energy have to be found in order to cope with possible fossil fuel scarcity. Among the renewable energy mix, biomass burning has an almost neutral CO2 balance, especially when local biomass sourcing is possible. Among the diverse biomass sources, agricultural by-products such as rice husk, corn waste, palm waste, sugarcane, date palm, olive mill wastewater… can be seen as renewable biomass fuels. The present study considers the combustion process of grape marc in a domestic boiler. The optimization of the heat recovery process was mainly carried out using grape marc blended with wood pellets and/or miscanthus. The combustion process was assessed considering the molar carbon ratio ([CO]/[CO]+[CO2]) and the total heat losses. These parameters have been chosen as they represent respectively the quality of the combustion in terms of CO conversion and the total efficiency of this combustion process. Gas and particulate matter emissions were estimated. It has been observed that the addition of grape marc with mass ratios in the range 25–33wt% has no significant effect on the combustion efficiency (molar carbon ratio lower than 1.3%) and on the Total Suspended Particles emissions (TSP ranged from 20 to 40mgNm−3 at 10% O2) for both mixtures. An efficient combustion of the blend miscanthus/grape marc at weight proportion 50/50 could also be achieved. The homogenization of mixtures of wood pellets and grape marc at 50/50wt% was difficult to realize and led to relative high CO emissions. Is has also been observed that Nitrogen Oxides (NOx) emissions depend on the nitrogen content of the blend but remaining acceptable (less than 260mg/Nm3 at 10% of O2). The feasibility of grape marc burning at domestic scale was therefore proved.

Thermodynamic Strategies for C-O Bond Formation and Cleavage via Tandem Catalysis.

To reduce global reliance on fossil fuels, new renewable sources of energy that can be used with the current infrastructure are required. Biomass represents a major source of renewable carbon based fuel; however, the high oxygen content (∼40%) limits its use as a conventional fuel. To utilize biomass as an energy source, not only with current infrastructure, but for maximum energy return, the oxygen content must be reduced. One method to achieve this is to develop selective catalytic methods to cleave C-O bonds commonly found in biomass (aliphatic and aromatic ethers and esters) for the eventual removal of oxygen in the form of volatile H2O or carboxylic acids. Once selective methods of C-O cleavage are understood and perfected, application to processing real biomass feedstocks such as lignin can be undertaken. This Laboratory previously reported that recyclable "green" lanthanide triflates are excellent catalysts for C-O bond-forming hydroalkoxylation reactions. Based on the virtues of microscopic reversibility, the same lanthanide triflate catalyst should catalyze the reverse C-O cleavage process, retrohydroalkoxylation, to yield an alcohol and an alkene. However, ether C-O bond-forming (retrohydroalkoxylation) to form an alcohol and alkene is endothermic. Guided by quantum chemical analysis, our strategy is to couple endothermic, in tandem, ether C-O bond cleavage with exothermic alkene hydrogenation, thereby leveraging the combined catalytic cycles thermodynamically to form an overall energetically favorable C-O cleavage reaction. This Account reviews recent developments on thermodynamically leveraged tandem catalysis for ether and more recently, ester C-O bond cleavage undertaken at Northwestern University. First, the fundamentals of lanthanide-catalyzed hydroelementation are reviewed, with particular focus on ether C-O bond formation (hydroalkoxylation). Next, the reverse C-O cleavage/retrohydroalkoxylation processes enabled by tandem catalysis are discussed for both ether and ester C-O bond cleavage, including mechanistic and computational analysis. This is followed by recent results using this tandem catalytic strategy toward biomass relevant substrates, including work deconstructing acetylated lignin models, and the production of biodiesel from triglycerides, while bypassing the production of undesired glycerol for more valuable C3 products such as diesters (precursors to diols) in up to 47% selectivity. This Account concludes with future prospects for using this tandem catalytic system under real biomass processing conditions.

Composição e dinâmica da avifauna da usina eólica da praia da Pedra do Sal, Delta do Parnaíba, Piauí, Brasil

RESUMO O impacto dos parques eólicos sobre as aves é um dos temas menos estudados no Brasil, o que contrasta com a importância dessa nova fonte de energia renovável. O presente estudo buscou caracterizar a composição e dinâmica ecológica das espécies de aves residentes e migratórias presentes na área da Usina Eólica da Pedra do Sal, em Parnaíba, Estado do Piauí. O estudo foi desenvolvido por meio de trinta e três amostragens distribuídas em dois ciclos sazonais completos (setembro de 2011 a agosto de 2013), através do método do ponto de escuta, dispostos na base de cada um dos aerogeradores. Foram registrados 6.843 contatos de aves pertencentes a 67 espécies distribuídas em 22 famílias e 13 ordens, e a espécie com maior número de contatos foi a batuíra-de-coleira (Charadrius collaris). As categorias tróficas predominantes foram as das aves insetívoras, representadas por 18 espécies, seguidas pelas aves que se alimentam de invertebrados aquáticos (17 espécies). A maioria das aves registradas é de ambiente aquático. Durante o desenvolvimento desse estudo não foram registradas colisões entre as aves e os aerogeradores.

Energy extraction from wind shear: Reviews of dynamic soaring

This paper presents a review of research works related to the application of dynamic soaring for extracting and collecting energy from certain structures in the wind using a small unmanned aerial vehicles (UAVs). By dynamic soaring, UAVs can extract energy from wind shear to produce electrical power or conduct a high-speed, long-endurance mission without adding extra weight. Combined with rapid technological development of UAVs, dynamic soaring might become a new way to explore nature's energy; extracted energy from wind shear might become a new source of renewable and sustainable energy. In this paper, we review the dynamic soaring and analyze the energy extraction process of it from the view of energy transformation. We also discuss the rate and efficiency of energy extraction as well as the possible applications, challenges and future of dynamic soaring in UAVs.

First-Principles Study of hydrogen retention and diffusion in beryllium oxide

In the quest of new renewable sources of energy, hydrogen is a promising candidate and its storage in solid-state materials is of extreme importance. Beryllium has been invoked in the past for this purpose because of its low density, and for the rather low energy of adsorption and retention of hydrogen that makes its restitution relatively easy, therefore it seems interesting to also investigate the properties of beryllium oxide. Hydrogen (and its isotopes) is also important as the fuel of deuterium–tritium plasma in tokamaks for energy production by magnetically confined nuclear fusion, when the plasma is in interaction with the beryllium (and beryllium oxide) of the inner walls of the device.Another interest of beryllium oxide (BeO) lies in its properties as a ceramic: high thermal conductivity, high electric resistivity, efficient accumulation of energy, and transparency to a large spectrum of radiations. The bad point is that beryllium oxide grows very easily as a film on pure beryllium sample and significantly perturbs the material properties on the surface in a manner that is not easy to comprehend.The dynamics of hydrogen atom retention in beryllium oxide implies the knowledge of its interactions of the atoms constituting the material, on the surface and in the bulk and in the defects present into this media. These defects can be native or generated by the hydrogen beam. This paper proposes a detailed calculation of energy trapping and diffusivity of interstitial atoms (hydrogen, beryllium, oxygen). Then the same kind of computations is described for atomic vacancies and the trapping of hydrogen atoms into these vacancies. The last step deals with the surfaces of beryllium oxide, their structures and reactivity to hydrogen.

海流発電装置設計における流速活用手法

Renewable energy has been an attention of scientists for last few decades around the world. Ocean current is also expected to be a new source of renewable energy and some types of Ocean Current Turbine is developed. For optimum ocean current turbine design, utilizing current velocity information is essential but the fact is that there is little information about current velocity and it is not organized well. Thus, in this study, a method to organize and utilize ocean current information based on power spectral model is proposed. Moreover, observation system for lack of data is considered and in-situ observation is conducted around the Kuroshio watershed area. As a result, fluctuation intensity range is quantified at the observed location and by applying current velocity reproduced from proposed spectral model, numerical simulation for design assessment gets easier. The load on the blade in time domain is estimated as an example and it would be used for the design.

Sediment microbial fuel cells as a new source of renewable and sustainable energy: present status and future prospects

SMFCs are a bioelectricity production technology for low power applications. Recent advances in SMFCs are investigated to enhance their performance. Power improvement and organic matter reduction in SMFCs enlarge their range of applications.

Perspective and Challenge of Tidal Power in Bangladesh

Tidal power can play a vital role in integrating as new source of renewable energy to the off-grid power connection in isolated areas, namely Sandwip, in Bangladesh. It can reduce the present energy crisis and improve the social, environmental and economical perspective of Bangladesh. Tidal energy is becoming popular around the world due to its own facilities. The development of any country largely depends on energy sector improvement. Lack of energy sector is because hampering of progress of any country development and energy sector will be stable by only depend on sustainable energy sources. Renewable energy is the only sustainable solution of secure energy which is environmental friendly. Bangladesh has a huge potential of tidal power at different locations but effective measure on this issue have not been considered sincerely. This paper summarizes the current energy scenario and Bangladesh can produce power approximately 53.19MW across the country to reduce the growing energy demand utilizing tidal energy as well as it is shown that Sandwip has high potential of producing tidal power which is approximately 16.49MW by investing only US $10.37 millions. Besides this, cost management for tidal power plant also has been discussed.

A global boom in hydropower dam construction

Human population growth, economic development, climate change, and the need to close the electricity access gap have stimulated the search for new sources of renewable energy. In response to this need, major new initiatives in hydropower development are now under way. At least 3,700 major dams, each with a capacity of more than 1 MW, are either planned or under construction, primarily in countries with emerging economies. These dams are predicted to increase the present global hydroelectricity capacity by 73 % to about 1,700 GW. Even such a dramatic expansion in hydropower capacity will be insufficient to compensate for the increasing electricity demand. Furthermore, it will only partially close the electricity gap, may not substantially reduce greenhouse gas emission (carbon dioxide and methane), and may not erase interdependencies and social conflicts. At the same time, it is certain to reduce the number of our planet’s remaining free-flowing large rivers by about 21 %. Clearly, there is an urgent need to evaluate and to mitigate the social, economic, and ecological ramifications of the current boom in global dam construction.

Metabolic engineering of fatty acids from soybean seeds

Background The worldwide demand for new renewable sources of energy is rising every day [1]. Biodiesel is a green fuel made mainly from soybean oil, on average composed of 25% oleic acid and 13% palmitic acid, which negatively impacts its oxidative stability and freezing point, causing a high rate of nitrogen oxide emission [2,3]. To improve the quality and performance of soybean oil as biodiesel, manipulation of its production of fatty acids is required to increase monounsaturated acids and reduce polyunsaturated acids. This work focuses on metabolic engineering of soybean to achieve those requirements.

ESTUDO DA VIABILIDADE DO USO DE RESÍDUOS LÍQUIDOS NO CULTIVO DA MICROALGA CHLORELLA SP VISANDO A PRODUÇÃO DE BIOCOMBUSTÍVEIS

The world is experiencing a global double crisis due to excessive use of fossil fuels and their harmful effects on the environment. Therefore, it is essential to obtain renewable energy sources. Thus arise the microalgae as an attractive option for renewable energy generation, as some species of microalgae contain lipids and carbohydrates that can be extracted for biofuel production. Microalgae also contribute to reducing the inappropriate release of wastewater, because they can be grown in culture media containing wastewater, reducing the pollution effect of the liquid waste. This work studied the cell growth of microalgae Chlorella sp in mixotroficos crops, through the addition of wastewater to the culture medium Bold’s Basal Medium. First glycerin used to culture medium in different ratios (2%, 4% and 10%), the results were not satisfactory for the development of microalgae studied, making it impossible to use glycerin for the cultivation of Chlorella sp. The second step consisted of supplementation of vinasse to the medium at different concentrations (10%, 15%, 20% and 25%), the results were satisfactory, since the slop had nutritional characteristics for the growth of microalgae. The proportion of vinasse that better growth was obtained with supplementation of 10% where found excellent adaptation of the cells to the new composition of the culture medium. With vinasse at levels greater than 10% in half, noted greater difficulty in cell growth due to excessive suspended material present in the vinasse favoring the drag of microalgae. Therefore, the results obtained from the use of vinasse concluded that its use is feasible for the cultivation of Chlorella sp, besides favoring a suitable destination for the liquid residue of sugarcane industries, also promotes the development of microalgae, enabling generation of new sustainable sources of renewable energy.

Characterization and Thermal Degradation of Rice Husk via TGA

New and renewable fuels are the major alternative to conventional fossil fuels. Biomass is a form of agricultural residues and is becoming popular among new renewable energy sources especially in an agricultural country such as Malaysia. Among the biomass, rice husk represents one of the highest agricultural wastes in Malaysia. Pyrolysis of biomass is one of the most important thermal conversion processes to produce bio-oil. The aim of the present study is to determine the characteristics and thermal degradation behavior of rice husk via thermal gravimetric analysis (TGA). Chemical analyses show that rice husk contains a high amount of organic constituents of hemi-cellulose (24%), cellulose (29%), and lignin (12.2%). Furthermore, the TG results show that the lignin is relatively more thermally stable than hemi-cellulose and cellulose. Evaluation of biomass resources as potential feedstock for conversion to bio-fuel generally requires information about proximate analysis, ultimate analysis, organic component analysis (hemi-cellulose, cellulose and lignin contents), and calorific value determination.

Design of Apparatus for Ni/Mg2Si and Ni/MnSi1.75 Contact Resistance Determination for Thermoelectric Legs

In recent decades, thermoelectricity has been widely studied as a potential new source of renewable energy. One of the major challenges to improve the efficiency of thermoelectric (TE) devices is to minimize the contact resistance between the active material and the electrodes, since this represents the major loss of charge in a TE module. This article describes the fabrication of an apparatus for TE leg characterization built with commercial and custom-made parts based on the analog one-dimensional transmission-line method. This device permits contact resistance measurements of bulk TE legs. p- and n-type TE materials, Mg2Si0.98Bi0.02 and MnSi1.75Ge0.02, respectively, were metallized with nickel foils and used as test materials for contact resistance characterization. Contact resistance values of 0.5 mΩ mm2 for Ni/Mg2Si0.98Bi0.02 junctions and 4 mΩ mm2 for Ni/MnSi1.75Ge0.02 junctions have been measured. Contact resistance measurements are discussed depending on materials processing and the experimental measurement conditions.