Nuclear Waste Reduction: Polymers Designed to Mop Up Radioactive Isotopes

Nuclear power could solve our energy problems but it has rather nasty by-products: radioactive waste. Not only the disposal of the old core rods but also reactor operation results in a large amount of low-level waste, especially contaminated cooling water.

Together with his colleague Sevilimendu Narasimhan from the Bhabha Atomic Research Center in Kalpakkam, India, the chemist PD Dr. Börje Sellergren from the Institute of Environmental Research at Technische Universität Dortmund has developed a new method to reduce the amount of this radioactive waste considerably. His approach: small beads consisting of a special polymer which “fishes” the radioactivity out of the water.

In pressurized-water reactors, the most common reactor, hot water circulates at high pressure through the steel pipes, dissolving metal ions from the walls of the pipes. When the water is pumped through the reactor’s core, these ions are bombarded by neutrons.

Because the pipes are steel pipes, most of the ions are common iron-isotopes (56 Fe), which don’t become radioactive when bombarded by neutrons. But the steel in the pipes is usually alloyed with cobalt. And when this cobalt absorbs neutrons, an instable cobalt-isotope (60 Co) emerges which is radioactive with a half-life of more than five years.

Usually the water is cleaned with ion exchangers. But this technique has a crucial disadvantage, because it doesn’t differentiate between non-radioactive iron-ions and radioactive cobalt-ions.

To overcome this problem, Sellergren and Narasimhan were looking for a material which binds cobalt and not iron. They developed a special polymer which is made through a procedure called “molecular imprinting.” This polymer is made in an environment containing cobalt. Then the cobalt-ions are extracted with hydrochloric acid, meaning that they are virtually “washed out.” The resulting cobalt-sized holes — the imprinting — are able to trap cobalt — and just cobalt — in other environments. The result: a small amount of this polymer can mop up a large amount of radioactive isotopes.

The team is now forming the polymer into small beads that can pass through the cooling system of a nuclear-power station. They expect that it would be more economical and environment-friendly to concentrate radioactivity into such beads than to dispose of large amounts of low-level waste. There obviously is a demand. Some 40 new nuclear-power stations are being built around the world. And the International Atomic Energy Agency estimates that a further 70 will be built in the next 15 years.

Story Source:

Adapted from materials provided by Technische Universitaet Dortmund, via AlphaGalileo.

http://www.sciencedaily.com/releases/2009/11/091127123921.htm

‘Cash for Clunkers,’ household edition

Program expected to boost appliance sales as economy drags

By Peter Whoriskey

Washington Post Staff Writer
Friday, November 27, 2009

In U.S. history, there may have been no better time to own a junk car, a rattling old fridge and a leaking dishwasher.

On the heels of its ballyhooed “Cash for Clunkers” program for cars, the federal government is expected to finalize details in the coming weeks of another tax-supported shopping extravaganza, known as “Cash for Appliances.”

Supported by $300 million from the economic stimulus, the program will offer rebates to consumers who buy energy-efficient refrigerators, dishwashers, air conditioners and other appliances to replace their older models.

And like the $3 billion cars program that gave consumers money for swapping their clunkers for more fuel-efficient rides, the appliance initiative seems destined to inspire shoppers, drive up sales for a while and profoundly divide economists over how much lasting good this chunk of government spending will do for the economy.

“The premise seems to be that for Americans to be richer, they need to throw out their old appliances faster — I don’t see it that way,” said James D. Hamilton, an economics professor at the University of California at San Diego, who has blogged about the clunkers rebates. “I don’t like the idea of just spending money for its own sake.”

While many economists believe that government incentives to lift consumer spending can boost the economy during a recession, they differ over whether the sales spikes that accompany the rebates are meaningful or merely concentrate sales that would have occurred before and after the rebate period anyway.

The Obama administration’s Council of Economic Advisers has indicated that the clunkers program provided a worthwhile boost even though many of the 690,000 clunkers sales would have happened anyway. In their baseline assessment, the program increased car sales in 2009 by 330,000.

Clunkers “is one of several stimulus programs whose purpose is to shift expenditures by households, businesses, and governments from the future to the present,” the council wrote in a September report. “Such time-shifting is valuable in a recession, when the economy has an abundance of unemployed resources that can be put to work at low net economic cost.”

The appliances program may be destined to continue the debate. For when it comes to stimulus, timing can be critical, and the implementation of the effort has dragged on, possibly diminishing its usefulness.

Although the $787 billion stimulus program was signed by Obama in February of 2009, much of the cash-for-appliances money won’t hit the streets until next February, March or April. The rebate program is being run by state governments, which must define and enact their rebate plans with federal government funding and approval. A survey of some of the largest states shows that California is planning to begin its program in March, New York in February, Pennsylvania in the spring, Illinois in January and April.

Under the program, Virginia is expected to receive $7.5 million, Maryland $5.4 million and the District $568,000, but the requirements and rebates have not yet been disclosed.

Now the home appliance manufacturers who celebrated the passage of the program worry that the delay in its implementation might actually depress sales at first, with consumers putting off purchases until the rebates begin.

“Our desire would be to see these programs rolled out as soon as funding is available,” said Jill Notini, a spokeswoman for the Association of Home Appliance Manufacturers. “Unfortunately, you may have people saying, ‘It’s kind of on the blink, but we’ll wait.’ We wish that the states would follow the intent, which is to stimulate the economy now.”

The number of shipments of home appliances in the United States, which is closely linked to new home construction, is down 12 percent from last year, Notini said, and this comes after three years of decline.

No one doubts that the appliances program will attract consumers. While the programs will vary by state, some of the proposed rebates that have been announced so far range from $50 to $100 per appliance. The state-administered programs also have varying requirements regarding whether consumers must recycle an old appliance to qualify for the rebate.

The states are required to estimate how many jobs their programs will create. California, which will receive $35 million, preliminarily estimated that it will create 350 jobs. This was based on the assumption that for every $92,000 expended, one job would be created.

Overshadowing the debate over the rebate program are questions regarding the health of the U.S. economy, which despite some signs of strengthening is still beleaguered by high unemployment. So while the rebates will be slower to get into consumer’s hands than some had hoped, some economists said the economy remains weak enough to justify the program even if it isn’t enacted yet.

“No one is saying we are going to have too much growth next year,” said Zach Pandl, an economist at Nomura Securities. “We want full employment of the economy’s resources, and we’re nowhere near that at this point.”

http://www.washingtonpost.com/wp-dyn/content/article/2009/11/26/AR2009112602420.html

Origami Solar Cells

Fold-up silicon: In these images, three thin films of silicon fold up into 3-D shapes under the force of surface tension as water droplets placed in their centers evaporate. The top row depicts the first step, when the water droplets are large, and the images below it show a time progression as the water droplets shrinks.   Credit: PNAS

Silicon sheets self-assemble into spheres to capture more light.

By Katherine Bourzac

One way to squeeze more power out of sunlight is to ensure that it always hits a solar panel at the ideal angle. This means either tracking the sun and maneuvering a panel to face it, or using complex optics to redirect the sun’s rays to hit the panel’s surface from above.

Researchers at the University of Illinois have now come up with self-assembling spherical solar cells capable of capturing more sunlight than flat ones. The shape is a simpler way to make more use of the sun’s rays, but has been difficult to realize in a solar cell. These new microscale solar cells are made using conventional lithography combined with self-assembly. If they prove practical, the devices could be wired up into large arrays that have the same power output as conventional cells, but that save on materials costs by using less silicon.

“Instead of a big slab of semiconductor fitted with concentrating lenses and motors to move it around, we want to make compact cells that still have a significant power output,” says Ralph Nuzzo, professor of chemistry at the University of Illinois at Urbana-Champaign.

Curved surfaces capture more light than flat ones because they have a greater surface area. But making solar cells that are curved or spherical is challenging, says Nuzzo, because the techniques used to process semiconducting materials such as silicon work best on flat surfaces. Nuzzo’s group has overcome this problem by making microscale 3-D structures that self-assemble from flat sheets.

The Illinois researchers start by treating the surface of a thin, high-quality silicon wafer and using conventional lithography to etch out a thin, two-dimensional shape. To make a sphere, the researchers cut the silicon into a flower shape. They then use an adhesive to secure a small piece of glass inside. The glass helps the structure maintain its shape once it is assembled. Finally, as a drop of water placed in the center of the flower shape evaporates, surface tension pulls its petals up, eventually bringing them together to form a sphere.

“The challenge in this is, how do you get things to follow the necessary sequence of steps to fold into the desired shape?” says Nuzzo. The Illinois group came up with mathematical models to help predict the mechanical properties of silicon sheets of different shapes and thicknesses, as well as how they interact with water, which can be tuned by chemically treating their surfaces.

Article Continues – http://www.technologyreview.com/biomedicine/24012/

Hydrogen-Economy on the Way? New Hydrogen-Storage Method Discovered

This schematic shows the structure of the new material, Xe(H₂)₇. Freely rotating hydrogen molecules (red dumbbells) surround xenon atoms (yellow). (Credit: Image courtesy of Nature Chemistry)

Scientists at the Carnegie Institution have found for the first time that high pressure can be used to make a unique hydrogen-storage material. The discovery paves the way for an entirely new way to approach the hydrogen-storage problem.

The researchers found that the normally unreactive, noble gas xenon combines with molecular hydrogen (H₂) under pressure to form a previously unknown solid with unusual bonding chemistry. The experiments are the first time these elements have been combined to form a stable compound. The discovery debuts a new family of materials, which could boost new hydrogen technologies.

The paper is published in the November 22, 2009, advanced online publication of Nature Chemistry.

Xenon has some intriguing properties, including its use as an anesthesia, its ability to preserve biological tissues, and its employment in lighting. Xenon is a noble gas, which means that it does not typically react with other elements.

As lead author Maddury Somayazulu, research scientist at Carnegie’s Geophysical Laboratory, explained: “Elements change their configuration when placed under pressure, sort of like passengers readjusting themselves as the elevator becomes full. We subjected a series of gas mixtures of xenon in combination with hydrogen to high pressures in a diamond anvil cell. At about 41,000 times the pressure at sea level (1 atmosphere), the atoms became arranged in a lattice structure dominated by hydrogen, but interspersed with layers of loosely bonded xenon pairs. When we increased pressure, like tuning a radio, the distances between the xenon pairs changed-the distances contracted to those observed in dense metallic xenon.”

The researchers imaged the compound at varying pressures using X-ray diffraction, infrared and Raman spectroscopy. When they looked at the xenon part of the structure, they realized that the interaction of xenon with the surrounding hydrogen was responsible for the unusual stability and the continuous change in xenon-xenon distances as pressure was adjusted from 41,000 to 255,000 atmospheres.

Why was the compound so stable? “We were taken off guard by both the structure and stability of this material,” said Przemek Dera, the lead crystallographer who looked at the changes in electron density at different pressures using single-crystal diffraction. As electron density from the xenon atoms spreads towards the surrounding hydrogen molecules, it seems to stabilize the compound and the xenon pairs.

“Xenon is too heavy and expensive to be practical for use in hydrogen-storage applications,” remarked Somayazulu. “But by understanding how it works in this situation, researchers can come up with lighter substitutes.”

“It’s very exciting to come up with new hydrogen-rich compounds, not just for our interest in simple molecular systems, but because such discoveries can be the foundation for important new technologies,” commented Russell Hemley, director of the Geophysical Laboratory and a co-author. “This hydrogen-rich solid represents a new pathway to forming novel hydrogen storage compounds and the new pressure-induced chemistry opens the possibility of synthesizing new energetic materials.”

This research was funded by the Department of Energy, Basic Energy Sciences hydrogen storage, and the National Science Foundation, Division of Materials Research.

Story Source:

Adapted from materials provided by Carnegie Institution, via EurekAlert!, a service of AAAS.

---

Journal Reference:

 

1. Maddury Somayazulu, Przemyslaw Dera, Alexander F. Goncharov, Stephen A. Gramsch, Peter Liermann, Wenge Yang, Zhenxian Liu, Ho-kwang Mao & Russell J. Hemley. Pressure-induced bonding and compound formation in xenon-hydrogen solids. Nature Chemistry, 2009; DOI: 10.1038/nchem.445

http://www.sciencedaily.com/releases/2009/11/091122161751.htm

Low-Carbon Fuel Rules

Slash and burn: California’s Low-Carbon Fuel Standard penalizes biofuels whose cultivation involves rainforest clearing– and thus worsen the greenhouse effect instead of easing it.   Credit: Martin Shields / Photo Researchers, Inc

California is about to implement a standard to boost cleaner fuels and punish the rest.

By Peter Fairley

Come January 1, fuel suppliers across California will have to abide by the state’s Low-Carbon Fuel Standard (LCFS). The standard aims to reduce the “life-cycle carbon intensity” of fuels consumed by cars, trucks, and other vehicles by 10 percent over the coming decade and, in the process, even the playing field for low-carbon alternatives.

This coming year a carbon intensity baseline for gasoline and diesel sold in California will be established. Each year thereafter, the state will set a standard that is progressively lower. Fuel distributors will need to reduce the carbon intensity of their fuel by blending in low-carbon fuels such as cellulosic biofuels, or by purchasing low-carbon credits earned by other firms that beat the standard.

“Those fuels with lower overall emissions will be incentivized, and those with higher emissions will be discouraged,” says Daniel Sperling, director of the Institute for Transportation Studies at the University of California, Davis and an architect of the LCFS.

Policy analysts such as Sperling predict that the LCFS will be the harbinger of smarter national and international fuel policies, in contrast to the rush into food-based fuels such as corn ethanol that offer little overall environmental benefit. “Until we adopt an LCFS nationally and internationally, policy will be politicized and ad hoc,” he says.

However, controversy has dogged measures pending in Washington and Brussels as scientists and politicians struggle for consensus on ways to evaluate life-cycle emissions. A flashpoint is whether and how to measure greenhouse gas emissions from indirect land use changes. An example of this would be the clearing of a forest to grow food crops to make biofuels.

What is clear is that the LCFS will help make some alternative fuel technologies more viable than others. Dan Kammen, co-director of the University of California’s Berkeley Institute of the Environment and another architect of the LCFS, says battery-powered vehicles should win big, given California’s preference for natural gas-fired power generation and the high efficiency of electric drivetrains. “Because of the very low emissions per mile traveled for electric vehicles versus all liquid fuels, the LCFS could strongly advance electrified transport,” says Kammen.

Electric vehicle players are already scrambling to capture the benefits. The California Air Resources Board in Sacramento has determined that charging an electric vehicle will result in 43 percent as much carbon dioxide emissions, mile for mile, as burning gasoline. Charging electric vehicles should thus generate credits under the LCFS that fuel companies can buy to offset the carbon-intensity of higher-carbon fuels.

Article Continues – http://www.technologyreview.com/energy/24003/

Ricardo Introduces Kinergy Flywheel Energy Storage System; FLYBUS and KinerStor

The Ricardo Kinergy high-speed, hermetically-sealed flywheel energy storage system.

Building on its experience in the research and development of advanced energy management concepts—including the engineering of kinetic energy recovery systems (KERS) for motorsport—Ricardo has devised Kinergy, a high-speed, hermetically-sealed flywheel energy storage system concept with an innovative and patented magnetic gearing and coupling mechanism.

The high power density and long-life potential of Kinergy technology combines both simplicity and effectiveness, avoiding the need for vacuum pumps and seals typically associated with high-speed carbon fibre based flywheel systems., Ricardo says. The lack of any mechanical coupling or other form of linkage through the system’s casing enables Kinergy to offer a robust, compact and lightweight package suitable both for incorporation into new product designs as well as retrofit applications aimed at improving the efficiency of existing vehicle fleets and industrial equipment.

<!––>Kinergy has the potential for use in a range of applications due to its comparatively very low projected production costs. Ricardo says that the technology is thus ideally suited for use in road vehicles where regenerative braking and torque assist is employed as a means of improving efficiency and hence reducing fuel consumption and CO₂ emissions. Such potential applications range from small, price-sensitive mass-market passenger cars to large luxury SUVs, buses and trucks.

Across all of these vehicle categories, Kinergy offers the prospect of enabling effective hybridization extending into market sectors where the use of conventional electro-chemical battery systems technology would be prohibitively expensive. Further potential Kinergy applications also include low-cost, compact energy management and storage systems for use in industrial and construction equipment, elevators, railway rolling stock, and local electrical substations and power distribution systems.

Cutaway of the FLYBUS with Kinergy system.

FLYBUS. The £1-million (US$1.7-million) FLYBUS project involves the development of a Ricardo Kinergy flywheel energy storage device incorporating a Torotrak patented Continuously Variable Transmission (CVT) for installation in a demonstrator vehicle based on an Optare Solo bus. Allison Transmission Inc. will also be involved, supporting the project with hardware and integration expertise.

Both technologies have already undergone development as part of a flywheel-based mechanical hybrid KERS which has been designed for use in motorsport. The mechanical hybrid system will offer the commercial vehicle sector a low-cost opportunity to deliver fuel efficiency savings of 20%. With further optimization, Torotrak believes that there are possibilities to significantly improve this.

The demonstration project will focus initially on installing an existing Torotrak CVT and Ricardo supplied flywheel in the Optare Solo bus, connecting the mechanical hybrid system directly to the Allison automatic transmission already fitted to the vehicle as standard equipment. The majority of the application, integration, development and test work will be undertaken by Torotrak in partnership with Ricardo, while Optare and Allison—providing, respectively, the test vehicle and an Allison 2000 Series transmission hardware together with control integration support—will also offer their series manufacturing expertise.

The Technology Strategy Board is to provide £0.5 million (US$0.83 million) for the FLYBUS research program as part of its Low Carbon Vehicles initiative, with the consortium partners jointly matching this investment. The aim is to demonstrate a flywheel-based mechanical hybrid system in an Optare Eco Drive Solo bus and to confirm the benefits of mechanical hybrid systems, effectively KERS-based technology, for fitment as original equipment in new commercial vehicles and also as a retrofit system for updating existing vehicles. The consortium plans to demonstrate the new low emissions, high fuel efficiency vehicle to bus companies, fleet operators and regulatory bodies both in the UK and beyond.

KinerStor. The KinerStor project will be led by Ricardo and will comprise a consortium of industrial partners including CTG, JCB, Land Rover, SKF, Torotrak and Williams Hybrid Power. The project aims to demonstrate the potential of flywheel-based hybrid systems with the potential for 30% fuel savings (and equivalent reductions in CO₂ emissions) at an on-cost of less than £1,000 (US$1,660), thus enabling the mass-market uptake of hybrid vehicles in price-sensitive vehicle applications.

The project will research and de-risk the principle critical flywheel sub-systems individually, then bring them together for system optimization in two forms of proprietary device; a mechanical/magnetic coupled flywheel system developed by Ricardo (the Kinergy system), and an electrically coupled unit developed by Williams Hybrid Power. The KinerStor project team aims to design, build and test a number of prototype units such that on completion, the developed technologies are ready for vehicle-based installation, testing and demonstration.

The KinerStor consortium brings together relevant skills and expertise in specialist areas, including: advanced flywheel systems, focusing on new material technologies including low-cost composite fibres and specialist steels; continuously variable transmissions; bearing and coupling design; drivetrain integration; and volume vehicle manufacturing. The project’s structure will allow for the development of common core-technology solutions which can be tailored to the individual needs of vehicle manufacturers, maximizing potential fuel saving and CO₂ emission reduction benefits.

The KinerStor project is supported by an investment from the UK Government-backed Technology Strategy Board with balancing resources provided by the project partners.

http://www.greencarcongress.com/2009/11/kinergy-20091124.html

Norway opens world’s first osmotic power plant

Norway opened on Tuesday the world’s first osmotic power plant, which produces emissions-free electricity by mixing fresh water and sea water through a special membrane.

State-owned utility Statkraft’s prototype plant, which for now will produce a tiny 2 kilowatts to 4 kilowatts of power or enough to run a coffee machine, will enable Statkraft to test and develop the technology needed to drive down production costs.

The plant is driven by osmosis that naturally draws fresh water across a membrane and toward the seawater side. This creates higher pressure on the sea water side, driving a turbine and producing electricity.

“While salt might not save the world alone, we believe osmotic power will be an interesting part of the renewable energy mix of the future,” Statkraft Chief Executive Baard Mikkelsen told reporters.

Statkraft, Europe’s largest producer of renewable energy with experience in hydropower that provides nearly all of Norway’s electricity, aims to begin building commercial osmotic power plants by 2015.

Here is the company’s illustration of how the plant works.

 

(Credit: Statkraft)

The main issue is to improve the efficiency of the membrane from around 1 watt per square meter now to some 5 watts, which Statkraft says would make osmotic power costs comparable to those from other renewable sources.

The prototype, on the Oslo fjord and about 40 miles south of the Norwegian capital, has about 2,000 square meters of membrane.

Future full-scale plants producing 25 megawatts of electricity, enough to provide power for 30,000 European households, would be as large as a football stadium and require some 5 million square meters of membrane, Statkraft said.

Once new membrane “architecture” is solved, Statkraft believes the global production capacity for osmotic energy could amount to 1,600 to 1,700 terawatt hours annually, or about half of the European Union’s total electricity demand.

Europe’s osmotic power potential is seen at 180 terawatts, or about 5 percent of total consumption, which could help the bloc reach renewable energy goals set to curb emissions of heat-trapping gases and limit global warming.

Osmotic power, which can be located anywhere where clean fresh water runs into the sea, is seen as more reliable than more variable wind or solar energy.

Story Copyright (c) 2009 Reuters Limited. All rights reserved.

 

Additional stories from Reuters

1. Carbon will mature as inflation hedge
2. Ex-BP renewables CEO to chair $1.5 billion carbon fund
3. Kenya sees geothermal power at 4,000 MW by 2030
4. Norway opens world’s first osmotic power plant

http://news.cnet.com/8301-11128_3-10404158-54.html?tag=newsEditorsPicksArea.0

Demonstrating a CO2 Recycler

Sun to syngas: This prototype, known as the CR5, was designed by Sandia researchers to convert carbon dioxide into carbon monoxide, or water into hydrogen, using concentrated solar energy. The carbon monoxide and hydrogen can be combined later to produce syngas, a building block for most transportation fuels. The first working prototype, shown above, has demonstrated that the process works, but efforts are underway to make it more efficient.   Credit: Tyler Hamilton

Sandia scientists successfully test a machine that creates fuel from carbon dioxide.

By Tyler Hamilton

Researchers at Sandia National Laboratories have successfully demonstrated a prototype machine that uses the sun’s energy to convert water and carbon dioxide into the molecular building blocks that make up transportation fuels. The “Sunshine to Petrol” system could ultimately prove a practical way to recycle CO₂ from power and industrial plants into gasoline, diesel, and jet fuel, assuming the process can become at least twice as efficient as natural photosynthesis.

Until recently, the system had only been validated in a laboratory in small batches. A hand-built demonstration machine was successfully tested this fall. “This is a first-of-its-kind prototype we’re evaluating,” says Sandia researcher Rich Diver, inventor of the device.

“In the short term we see this as an alternative to sequestration,” says James Miller, a chemical engineer with Sandia’s advanced materials laboratory. Instead of just pumping CO₂ underground for permanent storage, Miller says, the sun’s abundant energy can be used to achieve “reverse combustion” that essentially turns carbon dioxide back into a fuel. “It’s a productive utilization of CO₂ that you might capture from a coal plant, a brewery, and similar concentrated sources.”

The cylindrical metal machine, called the Counter-Rotating-Ring Receiver Reactor Recuperator (CR5), relies on concentrated solar heat to trigger a thermo-chemical reaction in an iron-rich composite material. The material is designed to give up an oxygen molecule when exposed to extreme heat, and then retrieve an oxygen molecule once it cools down.

The machine is designed with a chamber on each side. One side is hot, the other cool. Running through the center is a set of 14 Frisbee-like rings rotating at one revolution per minute. The outer edge of each ring is made up of an iron oxide composite supported by a zirconium matrix. Scientists use a solar concentrator to heat the inside of one chamber to 1,500 º C, causing the iron oxide on one side of the ring to give up oxygen molecules. As the affected side of the ring rotates to the opposite chamber, it begins to cool down and carbon dioxide is pumped in. This cooling allows the iron oxide to steal back oxygen molecules from the CO₂, leaving behind carbon monoxide. The process is continually repeated, turning an incoming supply of CO₂ into an outgoing stream of carbon monoxide.

Miller says the same process can be used to produce hydrogen, the only difference being that water, instead of carbon dioxide, is pumped into the second chamber. The two separately retrieved gases–hydrogen and carbon monoxide–are then mixed together to make syngas, which can be used to make a “drop-in replacement” for traditional fuels, says Miller.

Article Continues – http://www.technologyreview.com/energy/23996/

MIT researchers develop liquid metal battery for the grid and the home

By Joseph L. Flatley

We’ve see plenty of green power research over the years, from solar plants to underwater turbines , but relying on the sun or the sea for electricity is not without its challenges: the sun doesn’t always shine, for instance, and sometimes the water is calm. A group at MIT led by professor Donald Sadoway is developing grid-scale storage solutions for times when electricity isn’t being generated. Since these batteries are intended for the power grid instead of cellphones and Roombas, the researchers can use materials not feasible in consumer electronics — in this case, high temperature liquid metals. Besides being recently awarded a grant from ARPA-E (Advanced Research Projects Agency, Energy) to put these things in green power facilities, MIT has just embarked on a joint venture with the French oil company Total to develop a smaller-scale version of the technology for homes and office buildings.

http://www.engadget.com/2009/11/20/mit-researchers-develop-liquid-metal-battery-for-the-grid-and-th/

Engineers Use Aerospace Approach to Design Wave Energy System

Shown is the view from the far downstream end into the test section of the U.S. Air Force Academy water tunnel. Three blades of the cycloidal turbine are visible at the far end. Engineer Stefan Siegel and his colleagues test the turbine using the tunnel, with both steady and oscillating flow conditions simulating a shallow-water wave-flow field. (Credit: SSgt Danny Washburn, U.S. Air Force Academy, Department of Aeronautics)

The ocean is a potentially vast source of electric power, yet as engineers test new technologies for capturing it, the devices are plagued by battering storms, limited efficiency, and the need to be tethered to the seafloor.

Now, a team of aerospace engineers is applying the principles that keep airplanes aloft to create a new wave-energy system that is durable, extremely efficient, and can be placed anywhere in the ocean, regardless of depth.

While still in early design stages, computer and scale-model tests of the system suggest higher efficiencies than wind turbines. The system is designed to effectively cancel incoming waves, capturing their energy while flattening them out, providing an added application as a storm-wave breaker.

The researchers, from the U.S. Air Force Academy, will present their design at the 62nd annual meeting of the American Physical Society’s Division of Fluid Dynamics on Nov. 24, 2009, in Minneapolis, Minn.

“Our group was working on very basic research on feedback flow control for years,” says lead researcher Stefan Siegel, referring to efforts to use sensors and adjustable parts to control how fluids flow around airfoils like wings. “For an airplane, when you control that flow, you better control flight–for example, enabling you to land a plane on a shorter runway.”

A colleague had read an article on wave energy in a magazine and mentioned it to Siegel and the other team members, and they realized they could operate a wave energy device using the same feedback control concepts they had been developing.

Supported by a grant from the National Science Foundation, the researchers developed a system that uses lift instead of drag to cause the propeller blades to move.

“Every airplane flies with lift, not with drag,” says Siegel. “Compare an old style windmill with a modern one. The new style uses lift and is what made wind energy viable–and it doesn’t get shredded in a storm like an old windmill. Fluid dynamics fixed the issue for windmills, and can do the same for wave energy.”

Windmills have active controls that turn the blades to compensate for storm winds, eliminating lift when it is a risk, and preventing damage.

The Air Force Academy researchers used the same approach with a hydrofoil (equivalent to an airfoil, but for water) and built it into a cycloidal propeller, a design that emerged in the 1930s and currently propels tugboats, ferries and other highly maneuverable ships.

The researchers changed the propeller orientation from horizontal to vertical, allowing direct interaction with the cyclic, up and down motion of wave energy. The researchers also developed individual control systems for each propeller blade, allowing sophisticated manipulations that maximize (or minimize, in the case of storms) interaction with wave energy.

Ultimately, the goal is to keep the flow direction and blade direction constant, cancelling the incoming wave and using standard gear-driven or direct-drive generators to convert the wave energy into electric energy. A propeller that is exactly out of phase with a wave will cancel that wave and maximize energy output.

The cancellation will also allow the float-mounted devices to function without the need of mooring, important for deep-sea locations that hold tremendous wave energy potential and are currently out of reach for many existing wave energy designs.

While the final device may be as large as 40 meters across, laboratory models are currently less than a meter in diameter. A larger version of the system will be tested next year at NSF’s Network for Earthquake Engineering Simulation (NEES) tsunami wave basin at Oregon State University, an important experiment for proving the efficacy of the design.

The conference takes place from Nov. 22-24, 2009, at the Minneapolis Convention Center. The conference is the year’s largest devoted to fluid dynamics, bringing together researchers from across the world and across a wide range of disciplines.

The talk, “Deep Ocean Wave Cancellation Using a Cycloidal Turbine” is by Stefan Siegel, Tiger Jeans, and Thomas McLaughlin of the U.S. Air Force Academy.

Story Source:

Adapted from materials provided by National Science Foundation.

http://www.sciencedaily.com/releases/2009/11/091119111329.htm