Harvesting the sun's energy with nanoantennas

[OKIsItJustMe]

http://www.nanowerk.com/news/newsid=3902.php

Posted: January 4, 2008

Harvesting the sun's energy with nanoantennas

(Nanowerk News) Researchers at Idaho National Laboratory, along with partners at Microcontinuum Inc. (Cambridge, MA) and Patrick Pinhero of the University of Missouri, are developing a novel way to collect energy from the sun with a technology that could potentially cost pennies a yard, be imprinted on flexible materials and still draw energy after the sun has set.

The new approach, which garnered two 2007 Nano50 awards, uses a special manufacturing process to stamp tiny square spirals of conducting metal onto a sheet of plastic. Each interlocking spiral "nanoantenna" is as wide as 1/25 the diameter of a human hair.

Because of their size, the nanoantennas absorb energy in the infrared part of the spectrum, just outside the range of what is visible to the eye. The sun radiates a lot of infrared energy, some of which is soaked up by the earth and later released as radiation for hours after sunset. Nanoantennas can take in energy from both sunlight and the earth's heat, with higher efficiency than conventional solar cells.

"I think these antennas really have the potential to replace traditional solar panels," says physicist Steven Novack, who spoke about the technology in November at the National Nano Engineering Conference in Boston.

...

[OKIsItJustMe]

1. An image of the nanoantennas

http://www.inl.gov/featurestories/2007-12-17.shtml

An array of nanoantennas, printed in gold and imaged with a scanning electron microscope. The deposited wire is roughly a thousand atoms thick. A flexible panel of interconnected nanoantennas may one day replace heavy, expensive solar panels.

http://www.inl.gov/featurestories/2007-12-17.shtml

...

The team estimates individual nanoantennas can absorb close to 80 percent of the available energy. The circuits themselves can be made of a number of different conducting metals, and the nanoantennas can be printed on thin, flexible materials like polyethylene, a plastic that's commonly used in bags and plastic wrap. In fact, the team first printed antennas on plastic bags used to deliver the Wall Street Journal, because they had just the right thickness.

...

A charged future

One day, Novack says, these nanoantenna collectors might charge portable battery packs, coat the roofs of homes and, perhaps, even be integrated into polyester fabric. Double-sided panels could absorb a broad spectrum of energy from the sun during the day, while the other side might be designed to take in the narrow frequency of energy produced from the earth's radiated heat.

While the nanoantennas are easily manufactured, a crucial part of the process has yet to be fully developed: creating a way to store or transmit the electricity. Although infrared rays create an alternating current in the nanoantenna, the frequency of the current switches back and forth ten thousand billion times a second. That's much too fast for electrical appliances, which operate on currents that oscillate only 60 times a second. So the team is exploring ways to slow that cycling down, possibly by embedding energy conversion devices like tiny capacitors directly into the antenna structure as part of the nanoantenna imprinting process.

"At this point, these antennas are good at capturing energy, but they're not very good at converting it," says INL engineer Dale Kotter, "but we have very promising exploratory research under way." Kotter and Novack are also exploring ways to transform the high-frequency alternating current (AC) to direct current (DC) that can be stored in batteries. One potential candidate is high-speed rectifiers, special diodes that would sit at the center of each spiral antenna and convert the electricity from AC to DC. The team has a patent pending on a variety of potential energy conversion methods. They anticipate they are only a few years away from creating the next generation of solar energy collectors.

[phantom power]

2. clever

[losthills]

3. This is the kind of technology

that will turn giant coal and nuclear powered water boilers into antiques...

[The2ndWheel]

5. Also the kind of technology that will help us continue to

grow at the expense of the environment. We're not getting out of jail for free. The more energy we use, the more impact we will have. At every step, as we've used more and different kinds of energy(first just our own, then human and non-human slaves, then various substances we found in the ground), we've had greater and greater impact on our habitats. That will not change if we start using various substances that we find above the ground. If anything, we'll end up having a greater impact(we haven't had less impact yet as we've used more and more energy). It may not be carbon, but it will be something else(this is still existence we're living in...it's always something).

More energy use = more impact. We can't escape that.

[Zachstar]

8. Yes we can!

You fail to realize that this energy is NOT at the expense of the planet. This is taking energy that normally falls to earth and creates more heat that causes impacts.

The alternative is MUCH worse. Think about it!

We can either accept that the population growth is likely to never end so must be supported and eventually allowed to go to other worlds OR do nothing and they go into survival mode which means MASSIVE deforestation and utilization of coal to return to a steam economy.

People are not going to use less energy. China is proving that as more and more people get cars and use power from nasty coal fired plants. Get that thought out now.

So if we make those basic assumptions we can plan ahead and use technology to minimize the impact people have and to eventually give them the option to go elseware.

Let us say we hold the fort till 2070 or so and then some team invents a form of Faster than Light travel. Then if we hold the fort for a bit longer we can establish colonies elseware and give people the chance to go. At that point the population density is not likely to further expand.

[losthills]

10. I hardly think that preparing to leave the planet

constitutes a sound energy policy....

[tinrobot]

11. Faster than light travel?

You've been watching too much Star Trek.

It's always in our best interest to make the most of this planet, regardless of how fast we can escape it. Our planet is not just another disposable item that can be discarded when it's used up.

[Zachstar]

13. Tell that to the billions of people yet to be born...

Best interest or not all that many people could give a damn about what they do to make the most of the planet.

Take the case of the massive deforestation just to plant crops. Do you think if there are a billion more farmers they will say "Better leave the trees alone for the next generation!"

Like it or not there is no simple way to get out of this situation. It's either they stay about the same population except with steam economy that will dump insane amounts of carbon into the atmosphere. Or you accept that a new energy will likely cause massive population growth and plan for it ahead of time.

This isn't Star Trek. This is the reality of the future! Unless you are just fine with 10-20 billion people on the planet. Or a planet destroyed by the current population going to steam.

[tinrobot]

14. Steam economy?

How does staying at the same population equal a steam economy? I think technology like this solar array will move us way ahead of steam. That's the point of it.

But a solar array doesn't solve all of our problems, the biggest of which is overpopulation -- and you're right, there is no easy way out of that one. A few lucky souls escaping on a spaceship in 2070 doesn't really address that problem. If we don't change our reproductive ways, the planet will reduce the population for us, and if that happens, it won't be pretty.

[Zachstar]

16. Change our reproductive ways?

Sorry but human nature will render that completely void.

The part about the steam economy is exactly what I'm talking about when it comes to the planet reducing the population for us.

Oil runs low= people starting to starve= people going into survival mode and doing what they can to survive= Steam being brought up front= many tons of extra greenhouse gases and even worse from dirty coal= Climate Change at EXTREME rates= Ecosystem descrution= People starving again= Population not getting any higher.

Technology of the solar array is great, However it is nowhere near effective and cheap enough yet to power the machinery in the 3rd world that grows the crops. And even if it did. The population will just continue to grow till it outgrows that.

None of that has to happen if people would get SERIOUS about fusion NOW. Instead of thinking these side technologies will save the day.

[losthills]

15. How old are you, Dude?

[Zachstar]

17. What a silly post!

I guess I have to be 60 before I get any respect? Go bother someone else.

I don't have to be in the golden years to realize what is going on and how people are going the wrong way. I think the existing anti-nuke power movement that is STILL going after the existing plants is evidence enough that age matters little when it comes to intelligence.

[losthills]

19. I thought so....

[ladjf]

4. OKItsJustMe - Thanks for your hard work in keeping us all

posted on renewable energy news.

[OKIsItJustMe]

6. Thanks for noticing!

(Sometimes I wonder if I'm just wasting my time.)

[ladjf]

7. I read every one of your posts. You are among the few who fully

realizes how good the future could look if the human race uses its head.

[Zachstar]

9. Giving people somthing to hope for by posting such great articles is NOT wasting your time!

They are truly a flashlight in a dark room!

[tinrobot]

12. I like this quote:

The team estimates individual nanoantennas can absorb close to 80 percent of the available energy. The circuits themselves can be made of a number of different conducting metals, and the nanoantennas can be printed on thin, flexible materials like polyethylene, a plastic that's commonly used in bags and plastic wrap. In fact, the team first printed antennas on plastic bags used to deliver the Wall Street Journal, because they had just the right thickness.

By focusing on readily available materials and rapid manufacturing from inception, Novack says, the aim is to make nanoantenna arrays as cheap as inexpensive carpet.

This sounds very promising, and perhaps there is a use for all those recycled plastic bags.

[Zachstar]

18. Well I am not exactly ready to put plastic bags on top of my house.

I hope they will make "rolls" of this in material that is nice and weather proof as well as stable and nontoxic of course.

-------------

I wonder if they can be tuned to intercept other types of energy?

Obviously there is lots of energy in the visual spectrum. Perhaps even a usable bit in the UV these days.

Even better is perhaps these can absorb the radio spectrum? Not much energy but it's better than my body absorbing them day and night.