rilpoint_mw113

VATIS Update Non-conventional Energy . May-Jun 2008

Register FREE
for additional services
Download PDF
New and Renewable Energy May-Jun 2008

ISSN: 0971-5630

VATIS Update New and Renewable Energy (formerly Non Conventional Energy)* is published 4 times a year to keep the readers up to date of most of the relevant and latest technological developments and events in the field of New and Renewable Energy. The Update is tailored to policy-makers, industries and technology transfer intermediaries.

———————
* This update has been renamed as 'VATIS Update: New and Renewable Energy' from Jan-Mar 2015 onwards.

Editorial Board
Latest Issues
New and Renewable
Energy
VATIS Update Non-conventional Energy Apr-Jun 2017
Bio
Technology
VATIS Update Biotechnology Apr-Jun 2017
Waste
Management
VATIS Update Waste Management Oct-Dec 2016
Food
Processing
VATIS Update Food Processing Oct-Dec 2016
Ozone Layer
Protection
VATIS Update Ozone Layer Protection Sep-Oct 2016
Tech
Monitor
Asia-Pacific Tech Monitor Oct-Dec 2014

Contents

__NOTOCNUM__

IN THE NEWS

India offers incentives for solar power projects

The Ministry of New and Renewable Energy of India has announced a demonstration programme to support large grid-interactive solar power generation projects, up to a maximum capacity of 50 MW. Any registered company, as project developer, would be qualified to set up solar power projects on “build, own and operate” basis. Proposal from each project developer with a maximum aggregate capacity of 5 MW, either through a single project or multiple projects of a minimum capacity of 1 MW each, would be considered.

Projects with a maximum of 10 MW solar power generation capacity would be considered in a state. Projects from states where the State Electricity Regulatory Commissions (SERCs) have announced or are in the process of announcing solar power tariff would get preference. Projects that are approved and commissioned by 31 December 2009, will receive generation-based incentive from the Ministry – up to Rs 12 (US$0.30) per kWh for solar photovoltaic power and Rs 10 (US$0.25) per kWh for solar thermal power fed to the grid by the solar power project developers, after taking in to account the tariff provided by the SERC or the utility. The Ministry will also provide incentive to the concerned utility and the State Nodal Agency, which will be involved in implementation and monitoring of the projects in that state.



Source: www.pib.nic.in


Capital fund for European energy projects

European Commission said it has launched a Global Energy Efficiency and Renewable Energy Fund (GEEREF). The Commission said it will put €80 million into the fund from 2007 to 2010 to kick-start the initiative. It foresees a total initial funding from public and commercial sources of €150-200 million, and is expected to mobilize additional risk capital of at least €300 million, and possibly up to €1 billion, in the longer term. The fund will be used to secure private investments in energy efficiency and renewable energy projects in developing countries and economies in transition.



Source: www.forbes.com


China unveils renewable energy development plan

By 2010, China’s annual consumption of renewable energy will reach the equivalent of 300 million tonnes of standard coal, which would be 10 per cent of its total annual energy consumption, under the country’s renewable energy development plan for 2006-2010. The plan, released in March by the National Development and Reform Commission (NDRC), says renewable energy consumption in 2010 will be nearly double the 2005 level, which was equivalent to 166 million tonnes of standard coal. That led to an emission reduction of 3 million tonnes of sulphur dioxide and more than 400 million tonnes of carbon dioxide.


Given the dearth of petroleum and natural gas resources and the large share of coal in its energy production, it is difficult for China to sustain its development and protect the environment by relying totally on fossil fuels, NDRC said. China has abundant renewable resources that could be exploited. The plan says that by 2010:


• The nation will have hydropower projects with a combined installed capacity of 190 million kW and wind power projects with installed capacity of 10 million kW.
• Installed capacity of bio-energy projects will reach 5.5 million kW and that of solar energy projects will be 300,000 kW.
• Domestically produced hydropower equipment and solar water heaters should become competitive on global markets.
• Wind power equipment manufacturers should put generating units with installed capacities of at least 1.5 MW into mass production.


Source: www.news.xinhuanet.com


Fiji considers geothermal energy

Fiji is looking for alternative energy sources in the face of record-high fuel prices. The Ministry of Land and Mineral Resources and other stakeholders are studying three options – geothermal, solar and wind – for alternative energy bases, said the Interim Lands Minister, Mr. Netani Sukanaivalu.


Geothermal is the front-runner so far and two companies – Geothermal Electric Ltd. and Mitchell Morgan – have expressed interest in drilling for hot water springs in Fiji. Geothermal Electric reportedly intends to start drilling on state leases later this year, while Mitchell Morgan is expected to start work after completing its lease application. Areas where geothermal energy can be sourced have been identified around the country.


Alternative energy sources, especially geothermal, would help alleviate the high fuel costs, said Mr. Sukanaivalu. Fiji is one of the countries in the hottest geothermal sites in the world because of its location on the Pacific Rim.



Source: www.upi.com


Sri Lanka targets more power from renewable sources

Sri Lanka has set a difficult target to increase non-conventional, renewable energy to 10 per cent from current level of 4 per cent by 2017, said Power and Energy Minister Mr. W.D.J. Senevirathne, addressing the Washington International Renewable Energy Conference for 2008. “Our renewed pledge on renewable energy stems out from the unbearable cost of fossil fuel burdening my country at present,” he said.


The Minister emphasised that the shift from fossil fuel to renewable energy and the reduction of energy use are the two options currently available. The Sustainable Energy Authority was the flagship of the host of programmes to achieve the goals of increasing the renewable energy and energy efficiency, he said. The Minister stressed the importance of energy to a developing country like Sri Lanka.


Source: www.dailynews.lk


Bangladesh to tap renewable energy sources

In a massive move to search for alternative fuels for power generation, the government plans to increase power output using renewable resources by 10 per cent. At present, it is only 5 per cent, Power Ministry sources said. Dr. M. Tamim, Special Assistant to the Chief Adviser, said that “we are planning to take some realistic steps shortly” to step up the use of renewable and alternative energy sources like sunlight, wind and biomass for generating electricity.


Dr. Tamim said, “As per declaration we plan to reach a 100 MW production target from hydro sources. We are also keen to see the evaluation report on the Kutubdia wind pilot project, as the fate of this project will say what we could do with our islands in so far as electricity is concerned.”


The Power Cell in a study paper has said that about 2,200 MW of power could be generated by using alternative energy sources. It said that currently 4 MW of power is being produced by home solar systems and the future prospect of power generation by using solar energy is around 300 MW. It said up to 1,000 MW of power could be generated from wind energy by installing wind turbines along the coastline; at present, only 2 MW of power is being generated by wind energy. It also said that around 600 MW of power could be produced from biomass and 300 MW from co-generation.


Source: www.energybangla.com


Wind energy to address Viet Nam’s power shortage

Viet Nam, a country plagued by energy shortages, has great potential for developing wind energy, says an expert. Speaking at a conference in Ho Chi Minh City recently, Mr. Nguyen Hoang Dung, Grid Department head of Power Engineering Consulting Company No. 3, said around 28,000 square kilometres of the country’s land had an average wind speed of over 7 m/s at a height of 65 m above sea level. This speed, considered suitable for power generation by international experts, offers a potential of over 110,000 MW, he said.


Viet Nam, a survey by the World Bank revealed, has greater wind energy potential than Thailand, Lao People’s Democratic Republic and Cambodia. It can produce 513,360MW annually – 200 times the output of the Son La Hydroelectric Plant in North Viet Nam, Southeast Asia’s largest power plant, and ten times the entire national capacity forecast for 2020. Some coastal areas in the central and central highlands regions are deemed good places to set up wind farms, thanks to high “wind power density” and the wide open land.


Mr. Dung said the government had enlightened policies for harnessing wind energy. It funds programmes, surveys and experiments for the purpose, and allows tax-free import, production as well as transportation of equipment needed for developing technologies for renewable and new energy. But the development and exploitation of wind energy faces a barrier in the form of pricing.


State-owned monopoly power distributor Viet Nam Electricity (EVN) pays only US$0.45/kWh of wind energy though the cost of generating it is not less than US$0.60/kWh. Countries developing wind energy often provide subsidies, as costs cannot yet compare with that of traditional electricity. Mr. Dung said it was therefore necessary for the government to work on pricing.


Source: www.thanhniennews.com


Thailand to produce ethanol from cassava

Cassava could be the safest and most economic feedstock for the production of biofuel. Rich in carbohydrate, cassava is food for both humans and animals, and also an ideal crop for biofuels. Researchers are developing new processes and technologies for the cost-effective production of ethanol from cassava.


Scientists from Thailand’s Kasetsart University and the Cassava & Starch Technology Research Unit of the National Centre for Genetic Engineering and Biotechnology. The scientists found that the cost and time of cassava-based ethanol production can be minimized through the simultaneous saccharification and fermentation process, as in bioethanol production from cereals. Researchers have found cassava to be a better feedstock for the daily production of the two million litres of ethanol required for its 10 per cent fuel substitution plan. Thailand produces 20 million tonnes of cassava a year. The starch chip and pellet industry consumes about 80-90 per cent of the output. The balance is available for ethanol production, unlike sugarcane or molasses, which are in short supply in Thailand.



Source: www.financialexpress.com


India to set up National Biofuel Development Board

The Indian government is planning to set up the National Biofuel Development Board, and the Ministry of New and Renewable Energy has been given the responsibility of setting it up. The proposal for setting up of the Board including its draft terms of reference and composition has been submitted for necessary approvals.


Through the National Oilseeds and Vegetable Oils Development Board, the Ministry of Agriculture is providing subsidy to individual farmers and non-governmental organizations for producing tree-borne oilseeds, including biofuel crops, under the Integrated Development of Tree-borne Oilseeds Scheme. Under this, 30 per cent credit-linked subsidy is provided, which is linked with 50 per cent term loan to be taken from bank, and 20 per cent beneficiary share in the form of land, labour, etc. Furthermore, the Ministry of Rural Development has provided financial assistance of Rs 490 million (US$ 12.3 million) to nine selected states in 2005-2006 and Rs. 495 million (US$ 12.4 million) to 15 states in 2006-07 for the purpose of raising Jatropha and Pongamia seedlings and plantation.


Source: www.pib.nic.in


Key developments in China’s renewable energy sector

China is displaying surprising progress in renewables: for example, the country trails only Germany and Japan in solar photovoltaic cell output. There are several such examples that repudiate the clichés that circulate about China’s green energy potential.


A document released by New Energy Finance Ltd. and the Chinese Renewable Energy Industries Association shows that China is rolling out some really smart green energy policies. The country has released the Medium to Long-term Development Plan for Renewable Energy, setting national targets for all major renewable energy sectors for 2010 and 2020 respectively. It is implementing a plan to compensate grid companies for the additional cost of purchasing renewable power via a quota exchange system.


In the wind sector, China has made a breakthrough in installations of domestically manufactured wind turbines. Wind turbines made by domestic manufacturers account for 56 per cent of all installed turbines in China in 2007, exceeding those made by foreign and joint venture companies for the first time. At the end of 2007, installed wind capacity in China reached 6 GW. One quarter of this is in Inner Mongolia Autonomous Region, making it the first province/region in the country to have more than 1 GW installed.


China has kicked off development of grid-connected utility scale PV projects, with the National Development and Reform Commission implementing a plan to build 5 MW and larger solar photovoltaic plants in eight provinces in western China. Jinan, in Shandong province, hosts the first central government sponsored National Solar Heat Utilization Congress in China, which aims to popularize the installation of solar water heaters in buildings across the country.


China has also reformed the bidding system for the fifth round national concession wind projects so as to discourage cut-throat price competition. It has halted the approval of new grain-based biofuel projects and enacted policies to encourage non-grain biofuels development.



Source: www.businessweek.com


SOLAR ENERGY

Solar cells created with inkjet technology

Using the cartridge-based Dimatix Materials Printer (DMP) from Fujifilm, Konarka Technologies of the United States, has demonstrated the world’s-first fabrication of highly efficient solar cells using of inkjet printing technology. The technology operates by propelling variable-size droplets of liquid or molten material onto almost any medium. The most common type of computer printer, inkjet printers are also used in the production of many microscopic articles as well as to form conductive traces for circuits, colour filters in LCD and plasma displays.


The DMP used for the demonstration was a bench-top materials deposition system that uses Fujifilm’s inkjet technology and shaped piezo silicon MEMS fabrication processes in depositing picolitre-sized droplets of functional fluids on all types of surfaces. By employing single-use cartridges that researchers can fill with their own fluid materials, the DMP system minimizes waste of expensive fluid materials, thereby eliminating the cost and complexity associated with traditional product development and prototyping. The DMP is suitable for prototyping and low-volume manufacturing, and the technology is scalable from research & development to production.


Konarka says that organic solar cells can be processed with printing technologies with little or no loss compared with “clean room” semiconductor technologies, such as spin coating – a process used to apply uniform thin film solar cells to flat base materials. Inkjet technology also has the advantage of being compatible with various base materials and does not require additional patterning.


Source: www.gizmag.com


Solar cell efficiency increased with popcorn ball design

A new approach creates a dramatic improvement in cheap solar cells now being developed in laboratories. By using a popcorn-ball design – tiny kernels clumped into much larger porous spheres – scientists at the University of Washington (UW) were able to manipulate light and more than double the efficiency of converting solar energy to electricity. This could lead to a significant breakthrough in dye-sensitized solar cells, according to lead author Dr. Guozhong Cao, a professor of materials science and engineering.


Current prototypes of dye-sensitized solar cells can convert just over one-tenth of the incoming sun’s energy into electricity. This is about half as efficient as the commercial, silicon-based cells used in rooftop panels and calculators. One of the main quandaries in making an efficient solar cell is the size of the grains. Smaller grains have bigger surface area per volume, and thus absorb more rays. Bigger clumps closer to the wavelength of visible light, however, cause light to ricochet within the thin light-absorbing surface, giving it a higher chance of being absorbed.


The UW scientists made very tiny grains, about 15 nm across (3,500 grains lined up end to end would equal the width of a human hair). Then they clumped these into larger agglomerations, about 300 nm across. These larger balls scatter incoming rays and force the light to travel a longer distance within the solar cell. The balls’ complex internal structure, meanwhile, creates a surface area of about 1,000 sq. ft for each gram of material. This internal surface is coated with a dye that captures the light.


The team expected some improvement in the performance but what the scientists saw exceeded their hopes. The overall efficiency was 2.4 per cent using only small particles: the highest efficiency achieved for this material. With the popcorn-ball design, results showed an efficiency of 6.2 per cent, more than twice the previous performance.


The experiments were performed using zinc oxide, which is less stable chemically than titanium dioxide (TiO2) but easier to work with. The team is working to transfer this concept to TiO2. Dye-sensitized solar cells based on TiO2 are now at 11 per cent maximum efficiency. Dr. Guozhong hopes his strategy could push the solar cells’ efficiency significantly over that threshold.


Source: www.azonano.com


Increasing efficiencies for thin film solar cells

Researchers at the United States Department of Energy’s National Renewable Energy Laboratory recently announced that they have moved closer to creating a thin-film solar cell that can compete with the efficiency of the more common silicon solar cell. The copper-indium-gallium diselenide (CIGS) thin-film solar cell recently reached 19.9 per cent efficiency in testing at the lab, setting a new world record.

This is still far from the 42.8 per cent efficiency, achieved in July 2007 by a consortium of researchers led by the University of Delaware, using a technology that adds multiple innovations to a very high-performance crystalline silicon solar cell platform. However, there are big differences in the manufacturing costs of these two technologies, as well as in their potential fields of application.


Improvements in CIGS modules do not only come in increased efficiencies of the modules but also in other forms. SoloPower and Ascent Solar say that their modules will be flexible rather than on glass (flexible metal foil for SoloPower, high temperature plastic substrate for Ascent Solar) thus increasing the versatility and variety of potential applications.


Optimization of solar cell technologies is tackled in a different way at the Oak Ridge National Laboratory (ORNL). The ORNL pulse thermal processing is a revolutionary enabling technology for functionalizing nanomaterials due to its ability to control diffusion at the nanoscale. It employs a unique high-density plasma arc lamp, which is a very powerful radiant arc lamp. Power densities of 20,000 W/cm2 can be achieved over broad areas (up to 1,000 cm2) and can be pulsed in 1 millisecond. The inherent characteristics of this technology – high heating rate, short processing time and larger processing area – enable unique thermal annealing capabilities that can potentially revolutionize PV material systems.


Source: www.photonicsonline.com


World’s most efficient multicrystalline silicon solar cell

Mitsubishi Electric Corp., Japan, has scored a world record conversion efficiency rate of 18.6 per cent in a multicrystalline silicon (Si) solar cell. The cell uses the company’s new technology called “honeycomb texture”. The National Institute of Advanced Industrial Science & Technology, a public standards agency in Japan, measured the efficiency rate.


Thus far, the highest conversion efficiency rate of a multicrystalline Si solar cell was 18.5 per cent. This was achieved by the cell with a new electrode structure called the “back contact”, which was developed by Kyocera Corp. Mitsubishi’s latest development indicates that a cell with a standard electrode structure can provide higher conversion efficiency than that of a back contact cell. When the cell conversion efficiency improves from 16 per cent to 18 per cent, the output rises by 0.4 W per 150 mm square cell. With the use of a module composed of an array of 50 cells, the module conversion efficiency will increase by 20 W.


For forming a honeycomb textured structure, 100 million holes must be made by laser beams on a SiN film formed on the surface of a 150 mm square cell. One of the issues for mass-production is to improve the throughput of laser equipment, which will be developed in-house. The improvement in throughput will lead to a reduction in the production cost per output.


Source: www.techon.nikkeibp.co.jp


Cheap and more efficient solar cells

Plants can transport absorbed solar energy over long distances, typically about 15-20 nm, to a location where it is converted into chemical energy. This is because the chlorophyll molecules in their leaves are arranged in optimal sequence. Ms. Annemarie Huijser, working on her PhD at the Technology University, Delft, the Netherlands, attempted a partial recreation in solar cells of this process as found in plants.


She focused on dye-sensitized solar cells, which are similar to Grätzel cells. These comprise a semiconductor, such as titanium dioxide, covered with a layer of dye. The dye absorbs energy from sunlight and creates energy parcels known as excitons. These then need to move towards the semiconductor. Once the excitons reach there, they generate electric power.


“Excitons need to move as freely as possible through the solar cells in order to generate electricity efficiently,” says Ms. Huijser. Studying the best sequence of dye molecules enabled her to increase the average distance that the excitons move in the solar cell by twenty times, up to a distance of approximately 20 nm, comparable to systems found in nature. This greatly increases the efficiency of the cells. However, in order to make this new type of solar cells commercially viable, the mobility of the excitons needs to be increased further by a factor of at least three. Ms. Huijser believes that this is possible.



Source: www.sciencedaily.com


WIND ENERGY

Modular wind turbine

AeroVironment (AV) Inc., the United States, has developed a modular wind turbine system designed for installation on buildings in urban and suburban areas. AV defines a new category of wind energy systems that adds value to buildings and demonstrates clean energy at work by eliminating the support tower, reducing noise and vibration, as well as creating a sleek and adaptable housing that installs quickly and easily onto buildings, without penetrating the roof.


Property owners can integrate the Architectural WindTM systems easily into new and existing buildings, as they present a colour-matched, sleek series of specially designed, highly efficient and low profile wind turbines. These wind turbines are designed to install easily onto the building parapet, operating in plain site as an attractive complement to the building’s architecture. Furthermore, these turbines rotate at low wind speeds to generate clean energy. Architectural Wind turbine is claimed to be designed to offer cost per kW of installed capacity and an attractive return on investment.

Contact: AeroVironment Inc., Corporate Headquarters, 181 W. Huntington Drive, Suite 202, Monrovia, California, CA 91016, United States of America. Tel: +1 (626) 357 9983; Fax: +1 (626) 359 9628; E-mail: info@avinc.com.


Source: www.avinc.com


World’s first hybrid excitation wind turbine

Baotou Huiquan Rare Earth Industry Group, a Chinese conglomerate, is working on grid wind turbine at the megawatt level in collaboration with Inner Mongolia Science and Technology University and Baotou Aineng Control Engineering. The collaboration has resulted in the first ever dual armature hybrid excitation wind turbine.


The prototype generator was installed in July 2007 in the Baitou City for trial operation. The trial operation, which ran for more than 3,600 hours, showed that the new generator meet all technical indicators required, and is ready for mass-production. The conglomerate is currently working on the same type of generator at 1.5 MW and 2.5 MW levels. The 1.5 MW generator is expected to be off the assembly line by mid-2008. According to a plan, the conglomerate will produce 300 sets of 1 MW and 1.5 MW wind turbine this year, and will expand to 500 sets in 2010.


Source: www.most.gov.cn


Commercially integrated wind turbines

The world’s first-ever integrated wind turbines, installed on the Bahrain World Trade Centre, have begun to produce power. These turbines are the first to be integrated on a commercial building and are expected to meet 11-15 per cent of the power needed by the whole structure. The output of the turbines, as they work 50 per cent of the time, would be analysed in the next few months.


The elliptical shape of the two buildings is said to even accelerate the wind towards the turbines. As the Bahrain World Trade Centre is in direct path of the onshore breeze blowing from the Gulf coast, there will be no shortage of wind. According to the project manager, the cost of turbines was reduced to 3.5 per cent of the whole project’s costs. This means that, if the turbines work as expected, the project would be financially viable.



Source: www.goodcleantech.com


Floating wind power

Advances in floating platforms can take wind farms far from coasts, to reduce costs and skirt controversy. Technology developers have begun to step up work in floating turbines to make such off-shore farms feasible. Several companies are on their way to demonstrating systems by borrowing heavily from oil and gas offshore platform technology.


The Dutch floating-turbine developer Blue H Technologies launched a test platform off Italy’s southern coast last December. Recently, the company announced that it would install another test turbine off the coast of Massachusetts, the United States.

The test platform that Blue H towed put up in Puglia, Italy, is called a tension-leg platform. It is a conventional off-shore oil and gas platform design that floats below the surface, held rigidly in place by chains running to steel or concrete anchors on the seabed. Installed on top is an 80 kW wind turbine fitted out with sensors to record the wave and wind forces experienced 10 km off-shore. Much bigger floating versions – 2.5 MW and 3.5 MW – are under construction by Blue H.


Blue H turbine uses a two-bladed rotor – a design that lost out to the three-blade design in the 1990s as the wind-turbine industry scaled up. The noise and jarringly high rotation speeds that made two-bladers a loser on land are either irrelevant or an advantage off-shore. Faster rotation offers benefits. The 30-35 rpm frequency – twice that of a three-bladed turbine – is less susceptible to interference from the back-and-forth swing of the platform under wave action. Faster rotation also means less torque, meaning that the structure can be built lighter. The rotor, gearbox and generator are lighter than the lightest of comparable machines. The turbine and platform are cheaper to build. The net result is a highly competitive energy source. Blue H’s wind farms are expected to deliver wind energy for US$0.07-0.08 per kWh, roughly matching the cost of natural gas-fired generation and conventional wind energy.


Source: www.technologyreview.com


Windmill for seawater desalination

A traditional windmill that drives a pump: that is the simple concept behind the combined wind power and reverse osmosis seawater desalination system developed by the Delft University of Technology (TU Delft) in the Netherlands. The system involves a high-pressure pump, which pushes water through a membrane at a pressure of approximately 60 bar. This reverse osmosis membrane produces fresh water directly from seawater. The windmill is suited for use by, for instance, small villages in isolated and dry coastal areas.


The combination of windmills and desalination installations is already commercialized. The windmills produce electricity from wind power. The electricity is stored and subsequently used to drive the high-pressure pump for reverse osmosis. However, the storage of electricity is very expensive and energy is lost during conversion. In the TU Delftsystem, the high-pressure pump is driven directly by wind power. Water storage can be used to overcome calm periods. The storage of water is a great deal cheaper than that of electricity.


The windmill employed is one that is normally used for irrigation. These windmills turn relatively slowly and are very robust. Based on the windmill’s generation capacity at varying wind speeds, it is estimated that it will produce 5-10 m3 of fresh water per day – enough drinking water for a small village of 500 inhabitants. The first prototype built is already working at a location near the A13 motorway near Delft.

 

Source: www.waterandwastewater.com


Wind turbine design inspired by whales

Marine scientists have long suspected that humpback whales’ incredible agility comes from the bumps, known as tubercles, on the leading edges of their flippers. Scientists at Harvard University in the United States have now come up with a mathematical model that helps explain this hydrodynamic edge. The work gives theoretical weight to a growing body of empirical evidence that similar bumps could help make more stable airplane designs, submarines with greater agility, and turbine blades that capture more energy from the wind and water. The study was carried out by Mr. Ernst van Nierop, a PhD student at the School of Engineering and Applied Sciences at Harvard, mathematics professor Dr. Michael Brenner and researcher Dr. Silas Alben.


The advantage of the humpback- whale flipper seems to be the angle of attack it is capable of – the angle between the flow of water and the face of the flipper. When the angle of attack of a whale flipper – or an airplane wing – becomes too steep, the result is a stall.


In aviation, stall means enough air is not flowing over the top surface of the wing, resulting in increased drag and reduced lift, a situation that can cause a sudden loss of altitude. Previous experiments have shown, however, that the angle of attack of a humpback’s flipper can be up to 40 per cent steeper than that of a smooth flipper before stall occurs.

The Harvard research team showed that the tubercles change the distribution of pressure on the flipper so that some parts of it stall before others. Since different parts of the flipper stall at different angles of attack, abrupt stalling is easier to avoid. This effect also provides the whale more freedom to attack at higher angles and the ability to better predict its hydrodynamic limitations. The team found that the amplitude of the bumps plays a greater role than the number of bumps along a flipper’s leading edge.


Already, attempts are being made to incorporate the tubercle design into commercial products. WhalePower, Canada, has begun demonstrating the advantages of tubercles when they are integrated into the leading edges of wind-turbine and fan blades. Prototypes of wind turbine blades have shown that the delayed stall doubles the performance of the turbines at wind speeds of about 17 mph and enables the capture of more energy out of lower-speed winds. Tubercle-lined blades are also more stable, quiet and durable than conventional blades.



Source: www.technologyreview.com


New software for wind turbine design

Romax Technology, a global software and consulting firm based in the United Kingdom, has released its latest RomaxDesigner software package, Release 12.6. The new edition includes a completely new wind turbine-specific product line called RomaxWIND and several additional features within the Romax Durability and Romax Bearing product ranges. RomaxWIND provides an “all-in-one” software tailored for wind turbine applications and encompasses the design, sizing and optimization of drive-train systems.

It is also designed to be integrated within the design process and to harness existing investment in software tools. RomaxWIND provides interfaces to common analysis tools used up and downstream in the design, such as Simpack for more multi-body simulation and Garrad Hassan’s Bladed for whole turbine dynamics.


Source: www.windtech-international.com


Modified clutch helps to halve wind turbine weights

A novel mechanical power transmission system for wind turbines has cut their weight by about 50 per cent, as well as made them more efficient. The new system, based on a modified over-running sprag clutch and V-pulley assembly, was developed by Renold Clutches & Couplings of Cardiff in the United Kingdom. The modified assembly is connected to a gearbox via a torsionally rigid coupling. This allows the gearbox to change the pitch angle of the turbine’s rotors to suit different wind conditions.


In general, wind turbines use fixed-speed rotors and in high winds, they have to cope with large torque fluctuations that can cause variations in generator output power of up to 100 per cent. The new design counters this problem by using a gearbox and clutch combination that allows the rotor speed to be adjusted by varying the pitch angle of the blades. This allows the generator output to be at a constant level, regardless of fluctuations in wind speed. If an overspeed occurs, the rotor reaches a fully feathered position and cuts out, but the clutch allows the generator to continue running.


The new design, incorporated in a wind turbine with a swept blade diameter of 33 m and a top speed of 50 rpm, is about half the weight of conventional designs. This improves the cost-to-weight ratio and reduces operating costs, because only 3 per cent of the rated power is consumed by the components. Contact: Renold plc., Renold House, Styal Road, Wythenshawe, Manchester, M22 5WL, United Kingdom. Tel: + 44 (161) 498 4500: Fax: +44 (161) 437 7782.



Source: www.drives.co.uk



ASIAN AND PACIFIC CENTRE FOR TRANSFER OF TECHNOLOGY

This website is optimized for IE 8.0 with screen resolution 1024 x 768
For queries regarding this website, contact us
Copyright © 2010 APCTT | Privacy Policy | Disclaimer | Feedback