New Things in Science & Technology Thread

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Hairy Solar Panels Could Result From Nanowire Breakthrough



Solar panels are constantly improving and breaking records. We often hear about new exotic materials and strange shapes, but this could be the weirdest announcement yet: Researchers at McMaster University (coolest name ever) have succeeded in 'growing' light-absorbing nanowires made of high-performance photovoltaic materials on carbon-nanotube fabric. The nanowires are made from exotic materials like gallium arsenide, indium gallium phosphide, etc, and they can absorb more energy from the sun than silicon, allowing the creation of both efficient and flexible solar panels .

The aim is to produce flexible, affordable solar cells composed of Group III-V nanowires that, within five years, will achieve a conversion efficiency of 20 percent. Longer term, he says, it's theoretically possible to achieve 40 percent efficiency, given the superior ability of such materials to absorb energy from sunlight and the light-trapping nature of nanowire structures. By comparison, current thin-film technologies offer efficiencies of between 6 and 9 percent.
Wow. Up to 40% for flexible panels!

But if it is known that the exotic materials used here are more efficient than silicon at converting light into electricity, why aren't they already used? Cost. That's the beauty of the nanowire approach; Each nanowire is 10 to 100 nanometers wide and up to five microns long, so very little pricey metal is used, keeping material costs down. Yet because of their shape, they absorb light quite well.

The research team, led by Ray LaPierre, a professor in the university's engineering physics department, has been given three years to achieve its goals--backed by about $600,000 from the Ontario government and private-sector research partner Cleanfield Energy, a Toronto-area developer of wind and solar technologies.

Source: http://www.treehugger.com/files/2008...s_nanowire.php

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19.9%: New Thin Film Solar Efficiency Record



The US National Renewable Energy Laboratory (NREL) has created thin film solar panels that are very close to competing with their more traditional silicon-based cousins. "The copper indium gallium diselenide (CIGS) thin-film solar cell recently reached 19.9 percent efficiency in testing at the lab, setting a new world record."

19.9% refers to how much of the sun's light is converted to electricity by the panel. Multicrystalline silicon-based solar cells have shown efficiencies as high as 20.3 percent (without concentrators...), so thin film is very close. Any fraction of a percent makes a big difference over the decades of useful life of a panel.

Source: 19.9%: New Thin Film Solar Efficiency Record : TreeHugger

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CoolEarth Raises $21 Million for Solar Balloons



CoolEarth, a company we've briefly covered before, has created an innovative way to harness the sun's energy. Instead of large expensive solar panels or costly concentrating mirrors, the company is using balloons made of metalized plastic films. Half of the balloon is transparent, letting the light in to be concentrated into a small high-efficiency solar panel by the concave interior. Each is 2 meters across and, depending on the source, estimates vary from 500 watt to 1 kilowatt. They are supported by cables, leaving the ground below clear and limiting environmental impact.

The company has just raised $21 million, and it says that "this is just the initial closing of the round, [it could be extended] over the next 60 days." The company closed a $1 million round of angel investing last June. Read on for more photos and details.



CoolEarth concentrators are suspended in series on support and control cables stretched between poles.


Here we can see how little support material it takes to keep the balloons in place.

It is reported that CoolEarth is planning to build a solar farm in the 10 megawatt range in the next few years. It would use about 10,000 balloons over 80 acres.


Above we can better see what the insides of the solar balloon look like. Quite simple and elegant.

Video: ‪Inflatable Solar Collectors‬‏ - YouTube

Source:CoolEarth Raises $21 Million for Solar Balloons : TreeHugger

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Moth Eyes May Hold Secret to Better Solar Panels



We've always been fascinated with what engineers and scientists are working on to make solar power more efficient. From solar balloons to nanotech "hairy" panels, there are lots of promising developments out there.

Today, lets look at a new approach. It's kind of similar to the "hairy" solar panel mentioned above, but this time the inspiration comes from the natural world (aka biomimicry), more specifically from the eyes of moths.

Silicon is reflective, so a lot of light that could be turned into electricity is bounced back and lost. Anti-reflective coating is used, but its effectiveness is limited and it has downsides too. So while looking for a solution, researchers noticed that moths have very non-reflective eyes ("most likely an evolutionary defense against nocturnal predators").

Peng Jiang from the University of Florida:

Moth eyes have orderly bumps on their corneas. Jiang refers to these bumps as “nipples.” The nipples are in an array that creates a situation in which almost no reflection exists. [...]
Jiang says that a method of spin coating is used to create the effect. Nanoparticles in a liquid suspension are placed on a silicon wafer, similar to those used in solar cells. As the wafer is spun, the force created distributes the nanoparticles in the liquid. A sort of mask is created that can be used as a template. Etching is used to transfer the nanoparticle structure onto the silicon wafer beneath.

But most important: in addition to being technologically easy, the process is also inexpensive. The exact opposite of the current anti-reflective coating.

The moth-eye process creates panels that reflect less than 2% of light. That's a vast improvement over the "35 to 40 percent reflection rate seen without the anti-reflection coating layers."

Source: Moth Eyes May Hold Secret to Better Solar Panels : TreeHugger

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Finding Clever Ways to Make Cheaper Solar Panels



The type of silicon used in photovoltaic panels is expensive, and as long as supply is constrained, the price of electricity produced by solar panels won't be as cheap as it could be. This high price for silicon has benefits; it is an incentive for more companies to start producing the stuff, but in an industry that sees very fast growth, it is hard to catch up with demand.

In the meantime, others are working on ways to reduce the amount of silicon required in solar panels. Solaria is one of those. Their solar cells produce about 90% of a conventional solar panel's power, while using half as much silicon.

How do they do it? It's not quite as out there as hairy solar panels and moth-eyes, but it's clever: "Ordinarily, the silicon in a solar panel spans its surface, collecting light from as much area as possible. But Solaria slices the silicon into thin strips and spaces them apart so that they only account for about half the panel's area. A clear molded plastic cover collects light from the entire panel and funnels it to the strips of silicon." See below for two pics that illustrates the concept.







The savings occur because the molded plastic is less expensive than the silicon that is saved, and because Solaria uses equipment that has already been developed by the semiconductor industry instead of trying to develop its own (see pic of robotic arm below).


They claim that their first products will be competitive in price with panels produced by much larger companies, and that successive product generations will cost between 10-30% less than their competitors.

Another benefit of Solaria's approach over traditional solar panels is that the space between the silicon strips can be used to route the wires that collect the electricity, thus taking them out of the sun's way.

To date, Solaria has raised $77 million to develop its technology, with the world's largest solar cell maker, Q-Cell, acting as a primary investor.
We wish them the best of luck, and we're happy to see yet another approach to making solar cheaper. There is no silver bullet.

Source: Solaria: Finding Clever Ways to Make Cheaper Solar Panels : TreeHugger

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New Solar Power Plant in Spain Produces Energy 24/7



Recently a company called Torresol Energy managed to solve one of the biggest issues linked with harnessing solar energy.

It managed to create a 19.9 megawatt Gemasolar concentrated solar power plant, which is located in Andalucia province, Spain. The plant features 2 tanks of molten salt that gather heat energy produced throughout the day. Thus it can generate electricity 24 hours a day.



The term "solar plant" is often associated with a plant that makes use of solar panels to produce energy. However, Gemasolar represents a plant that belongs to the category of Concentrating Solar Power (CSP) plants. These solar plants make use the sun's energy to heat a certain fluid, be it water or molten salt, to produce steam. The latter drives a turbine to produce power.

The plant consists of thousands of square meters of mirrors (and not solar panels). These mirrors are used to concentrate the same sunlight in one point (similar to when you use a magnifying glass). Then the fluid that flows past the focal point heats up to hundreds of degrees Celsius and makes use of the heat to power a turbine.

The new solar plant consists of 60 percent potassium nitrate and 40 percent sodium nitrate and the fusion of the two allows retaining 99 percent of the heat energy produced by the plant. This energy is later reused.

The somewhat small Gemasolar plant will be able to generate about 110,000 MWh of energy each year, which is enough to supply with energy over 25,000 homes.

It is worth mentioning that the plant was designed to work 6,500 hours annually. This concentrated solar power plant was officially launched in May 2011.

Video: ‪Gemasolar - The World's First Baseload (24/7) Solar Power Plant‬‏ - YouTube
Source:The World’s First Baseload (24/7) Solar Power Plant - Tony Seba - Clean Energy and Entrepreneurship - Forbes

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World's First Computer-Controlled Heliostat System for Heating and Lighting



A company called Practical Solar managed to create the world's first heliostat system that is controlled by a computer. With its help the sunlight provides enough energy for heating, lighting and other purposes.

The computer-controlled system takes advantage of the solar light even when it doesn't reach your house directly. One can install the heliostat system using only hand tools. The entire hard work is performed by the high-tech tracking technology software. The program regulates the focus and the angle while the sun moves.

Cutting down costs and saving energy use are the two main advantages of a heliostat, which can be used to direct natural sunlight in through a window. You can also use a number of heliostats in order to reflect natural lighting into a room.

When there's bright sunlight outside, one heliostat generates visible light that is equal to forty 100-watt incandescent light bulbs. In addition, the sunlight can cover an entire room in contrast to a limited range of a bulb. With the help of two heliostats one can generate about 600 watts of solar thermal energy. If a thermal receiver is added to accumulate heat then there will be enough energy to light up the house during the night.

With the help of individual heliostats you can have several targets, meaning that a heliostat can be used for a variety of tasks in different times, during different seasons. You can change the targets on demand or automatically with the help of timer function. It is worth mentioning that one heliostat uses less that 1/3,000 of the energy it generates. One driver box can control 200 heliostats

Source:Practical Solar | Making Solar Practical

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Scientists Study Butterfly Wings to Make Solar Cells More Efficient



Scientists say that the structures that disperse light, making the wings of butterflies so outstanding, could be used to develop cheaper and more efficient solar cells. It is worth mentioning that a solar cell (also called photovoltaic cell) is a tool that transforms solar energy into electricity through photovoltaic effect.

Within dye-sensitive solar cells a color covering on a titanium dioxide surface creates a so-called photoanode, which soaks up photons and draws off electrons.

In order to improve the efficiency of the solar cells, Di Zhang, a scientist of Shanghai Jiao Tong University in China together with his team decided to borrow the light-absorbing features of the wings of the Paris peacock butterfly, reports New Scientist.

Researchers soaked the samples of the butterfly's wing in a solution that included titanium. Afterwards they processed the wing to create a titanium dioxide deposit that replicated its honeycomb structure. After using this to create photoanode, scientists noticed that the efficiency of the cell was 10 percent higher than normal.

Source: Scientists Study Butterfly Wings to Make Solar Cells More Efficient*|*MaloMaaL.com

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Vulture - The Unmanned Aircraft Able to Stay in the Air for 5 Years



[img]http://4.bp.blogspot.com/_YRB7B2El99c/TM5iNoVVY2I/AAAAAAAAADY/yZrEv2llY8k*******vulture-03.jpg[/img]

Officials from Flight Global stated that DARPA will probably sign a contract to create an unmanned aircraft that is able to stay in the air for about 5 years at a time. The representatives from DARPA characterize their project, entitled "Vulture," as a "persistent pseudo-satellite capability in an aircraft package." Generally speaking the aircraft is able to fly over a single area, communicating or performing analysis for years at a time.

Having such grand goals the company has to overcome some serious barriers. One of the major obstacles is linked with the fact that designers have to figure out the way to supply power to such an aircraft during the long missions. In addition it is worth mentioning that the aircraft will carry a 1000 pound (450 kg) payload in terrible winds at an altitude of 60,000 to 90,000 feet. In regard to the design of the aircraft, it will probably be the one seen in the picture, developed by NASA, however, there is no certain time table on when the craft will actually be ready.

US Defense Advanced Research Projects Agency looks forward to push the limits of unmanned aviation to extremes. The latest UAV project of DARPA currently raises eyebrows.

"We want to completely change the paradigm of how we think of aircraft," stated Daniel Newman, who holds the post of Vulture project manager. "Aviation has a perfect record - we've never left one up there. We will attempt to break that record," he added.

"The ability to "close the business case" on an aircraft that could be launched and then not maintained or brought home for five years would be a "paradigm shift. We would no longer define an aircraft by the launch - recover - maintain - launch cycle," outlined Newman.

Besides problems with providing power to the craft, engineers are working on maximizing aero-structural efficiency and avoiding the deterioration of materials during their long-time exposure to stratospheric flight.

Basically the aircraft operates like a satellite, which is, however, not regulated by orbital mechanics. "It could be positioned over the battle, at 65,000ft versus 260 miles," outlined DARPA's Wade Pulliam. According to Pulliam, the Vulture is a pseudo-satellite, the operation of which in the stratosphere and not in the low Earth orbit would give a 65 dB upgrading in communications capability and considerably increase onboard sensor resolution.

Technology has come a long way in the past few decades and the advances don't appear to be slowing down anytime soon. From laptops and cellphones to the advent of Internet communications, we are moving toward a brave new world of possibilities. Even buying a new computer is tricky, since it'll probably be outdated by the time you open the box!





Source: http://www.tecpill.com/2011/05/vultu...nned-aircraft/
3gworld: Vulture Unmanned aerial vehicle

[jackdi]

Nice posts Master!
Post pa please.

If naa kay DIY solar project diha, post pod nya ha.
Thanks.