Solar dyes give a guiding light
Posted by Laird on Jul 29, 2008
Current solar plants need large mobile mirrors to produce energy
A new way capturing the energy from the Sun could increase the power generated by solar panels tenfold, a team of American scientists has shown.
The new technique involves coating glass with a specific mixture of transparent dyes which redirect light to photovoltaic cells in the frame.
The technology, outlined in the journal Science, could be used to convert glass buildings into vast energy plants.
The technology could be in production within three years, the team said.
“It makes sense to coat the side of [very tall] buildings with these new panes,” Professor Marc Baldo, one of the researchers on the team, told BBC News. “It’s not far fetched at all.”
Colour trick
The most advanced attempts to generate large amounts of electricity via the Sun require the use of a solar concentrator.
These are often bulky mobile mirrors that work by tracking the progress of the Sun and concentrating its beams on the cell at its heart.
But there are downsides to this technology: the cells at the centre have to be constantly cooled, and each concentrator requires a large amount of space to avoid shadowing its neighbour.
The technology collects and focuses different colours of sunlight
The technology collects and focuses different colours of sunlight
The new technology does away with the need for mirrors and mobility.
The Massachusetts Institute of Technology (MIT) team has found a way
to coat panes of glass or plastic with a mixture of several dyes that essentially do the same job.
“What we have is a piece of glass, with a very thin layer of paint or dye on top,” explained Professor Baldo.
“The light comes in and hits the dye and which absorbs it and re-emits the light, but now it’s inside the glass so it bounces along there until it gets to the edge. So you only need to mount the solar cells around the edge.”
The idea was first developed in the 1970s but was abandoned because much of the light energy was lost en route to the cell.
But using its expertise in optical techniques and a specific mixture of dyes, the MIT team has found a way to make the light travel much farther without losing as much energy along the way.
Window future
“When you do this there is a little bit of energy loss with the dye,” said Professor Baldo.
“The main benefit is with the cost. You use a far smaller amount of solar cells. For the same area of solar cells, you get much more electricity.”
Existing solar installations could also benefit from the new concentrator, he said.
“You could take this new kind of glass and put it on top of an existing solar cell so the cell still generates electricity but this glass pane with the dye on top captures a certain part of the spectrum and converts it more efficiently than the solar cell would do on its own.”
The MIT team believes it could improve existing panels by 50%.
In addition, the system is simple to manufacture, requiring little more than to coat glass or plastic with the combination of dyes. It could be in production within three years, the researchers believe.
If that becomes a reality, one obvious application, they said, was converting windows into energy plants.
“The coated glass would let through about 10% of the Sun to light up the room, and the remainder would be captured and funnelled to the edges to solar cells to generate electricity,” said Professor Baldo.
“It would look like smoked glass because of the dyes.”
By Matt McGrath
BBC science correspondent
Anaconda, the wave power generator
Posted by Laird on Jul 20, 2008
Anaconda, the wave power generator
Looking like something out of a Fifties B-movie, it slithers and slides through the waves.
But far from being a deadly predator, the 600ft-long rubber sea snake could one day be the answer to the country’s energy crisis. The device - named the Anaconda after the large snake that lives in water - is a wave power generator, which converts the rise and fall of the oceans into cheap, green electricity.
How the devices might look in the sea.
Its creators say it could offer a reliable alternative to the thousands
of wind turbines due to be built in the next decade.
Professors Francis Farley and Rod Rainey, the snake’s inventors, predict that, if tests continue to be successful, the first ‘Anaconda farms’ could be built within five years. The device, which is 20ft wide, is made up of a long rubber tube, closed at both ends and filled with water. Designed to be anchored with one end facing the oncoming waves, it should be used in water between 120ft and 300ft deep, typically about one or two miles from shore. Because it is made of rubber - meaning it is lighter than other wave generators and does not need complicated hydraulic ramps, hinges and articulated joints - it is cheaper to build and needs less maintenance.
A computer-generated image shows a ’snake farm’, each Anaconda providing ‘green’ energy
Tests using small-scale models of the device at Southampton University suggest each Anaconda could provide one megawatts - enough to provide energy for a few hundred homes.
Project director Tom Roach said the best sites for the farms would be off the west coast of Scotland and Ireland, or the South-West of England.
‘It works best where you have these large sea swells generated over long distances,’ he added. ‘They would have little environmental impact because they’re designed to float below the surface.’ He said a study by the Government’s-Carbon Trust found the Anaconda tubes could produce electricity more cheaply than offshore wind farms. Professor John Chaplin, who is leading the research, said: The Anaconda could make a valuable contribution to environmental protection by encouraging the use of wave power.’Snakes Alive! Each Anaconda could create enough electricity to power ‘a few hundred homes’
The snakes would be placed in water between 120 and 300 feet deep, and would be submerged under the surface
Wind Power F.A.Qs
Posted by Laird on Jul 13, 2008
How does Wind Turbines work?
A wind-Turbine generator installed on top of a tower or your home that will convert the kinetic energy in the wind into electricity to be used in a home’s electrical system.
In a typical residential application, a home is served simultaneously by the wind-Turbine generator and a local utility (or if you have a bi power wind/solar power system). If the wind speeds are below “cut-in speed” (8 mph) there will be no output from the generator and all of the needed power is purchased from the utility or . As wind speeds increase, the Turbine output increases and the amount of power purchased from the utility is proportionately decreased. When the Turbine produces more power than the house needs, the meter spins backwards creating a “credit” that can be used later. All of this is done automatically without any interaction by the homeowner. Batteries are not required with a Bi energy setup.
Can I run my wind turbine along side my Solar panels?
Yes you can combine both Wind & Solar power inputs to work together with your local utility.
Will A Wind turbine save me money?
Depending on the wind speed average and the amount of energy consumed every month, a turbine typically lowers a household electricity bill by 30% to 80%. It is not uncommon for Turbine owners with total-electric homes to have monthly utility bills of only $8 to $15 for nine months of the year. The amount of money a micro turbine saves you in the long run will depend upon its installed cost, the amount of electricity you use, the average wind speed at your site, and other factors.
Will it help the environment if I install a Wind turbine at my home?
Because a wind powered turbine is a renewable energy source, produces no pollution, and uses wind power, you will be offsetting pollution that would have been generated by your utility company. Over its life, a turbine can offset more than 6000 pounds of global warming pollutants (carbon dioxide and other gases that are associated with global warming) every year.
Does a turbine create and sound or interfere with TV reception?
A Micro turbine is extremely quiet and makes a small amount of operating sound similar to the level of a small office. It generally cannot be heard over typical background noise such as the sound of the wind. Turbines does not interfere with TV reception.
Is a wind turbine dangerous to birds?
While no formal studies have been done, anecdotal evidence indicates that birds occasionally collide with small wind generators as they do with any other type of structure. However, such events are very rare.
Should my neighbours be concerned about safety if install a wind turbine ?
No. our turbines design was done in collaboration with the U.S. Department of Energy and the National Renewable Energy Laboratories. As part of this project, extensive computer modelling and field testing was done to ensure a safe design. All of Turbine testing was done to internationally accepted standards for small wind safety and reliability. Your neighbours’ who may have some concerns about safety may appreciate the following information:
Tower stability: Thousands of small wind generators are installed in the U.S. every year and their safety track record is excellent. Trees are much more likely to fall than a properly installed turbine, but no setbacks or minimum property sizes are required for trees.
Safety of utility repair personnel during a power outage: In accordance to IEEE and UL, our turbines will automatically shut down in the event of a power outage, and will not energize a dead power line. This is necessary to protect the utility line repair person.
Ice shed from rotor blades: Ice buildup makes wind turbines blades less aerodynamic, so that they turn more slowly. Typically, ice will drop to the base of the generator tower and is not dangerous.
Children and towers: In terms of educating children about not climbing structures, a small wind generator should be treated no differently than other climbable structures such as water towers or amateur radio antennas.
Will a Wind turbine damage neighbouring property values?
No. With thousands of small wind generators installed today in the U.S., there has never been any evidence to support this claim. Actually, there are several survey sources that indicate otherwise.
Will my utility allow me to hook up a Wind turbine?
Yes. Federal regulations (specifically, the Public Utility Regulatory Policies Act of 1978, or PURPA) require utilities to connect with and purchase power from small wind energy systems. Your dealer should be able to help arrange the required utility company approvals.
Will my local government allow me to install a Wind turbine?
A Large wind turbine is a structure that normally requires a building permit. Zoning regulations often limit the height, placement, and other characteristics of “appurtenant” structures, so a conditional (special) use permit or variance may be necessary.
Will I have to change any of the wiring in my house?
No. Our turbines can easily be installed at any existing home without the need to change any wiring or appliances. In most cases, the utility will install a second utility meter to measure how much surplus electricity it is receiving from the generator owner.
What about towers?
Towers as short as 35 feet are available with our turbines. However in some circumstances, a taller tower may be necessary to raise the generator above turbulence created by obstacles on the ground and/or trees. Wind speed increases with height above ground, and increasing speed increases the amount of energy your generator will produce. Relatively small investments in increased tower height can yield high rates of return in energy production. A rule of thumb for proper and efficient operation of a Turbine suggests that the generator should be 20 feet (6 meters) above the top of anything within 300 feet (about 100 meters).
Methane Mammals part 2
Posted by Laird on Jul 11, 2008
Scientists collect cow farts in global warming study.
This cow knows that talk about global warming isn’t all hot air as its farts are collected in a tank strapped to its back.
Scientists want to know how much of a belch is methane - 23 times worse for the planet than carbon dioxide.Guillermo Berra, part of the Argentine research team, said: “When we got the results we were surprised. Thirty per cent of Argentina’s emissions could be from cows.”One can produce 1,000 litres of emissions daily. Poooohy :-}
Wind belt generator
Posted by Laird on Jul 6, 2008
Shawn Frayne invented an inexpensive non turbine wind generator called the wind belt. I have no specs other than what you see on the video. I imagine it’s use on the roof of an electric car but obviously it can be used anywhere there is wind. The bennefit is that it is very inexpensive to build as opposed to a standard turbine wind generator.
The fan simulates the wind which moves the belt which moves the magnets through the coils to make electricity to power the clock and LEDs. I don’t know how much the output voltage is.
The Windbelt is a device for converting wind power to electricity. A windbelt is essentially an aeolian harp except that it exploits to motion of the string produced by the the aeroelastic flutter effect to move a magnet closer and farther from one or more electromagnetic coil(s) and thus inducing current in the wires that make up the coil.
A famous example of aeroelasticity is the fall of the original Tacoma Narrows Bridge, which became known as Galloping Gertie and is commonly shown to engineering, architecture, and physics students as a cautionary tale.
Prototypes of the device are claimed to be ten-to-thirty times more efficient than wind microturbines, even though greater than 100% efficiency is not physically possible. One prototype has successfully powered two LEDs, a radio, and a clock using wind generated from a household fan. The cost of the materials was well under US$10, giving a savings of 10s of dollars per watt.
