For our modern, technologically-advanced society, in which technology has become the solution to a myriad of challenges, energy is critical not only for growth but also, more importantly, survival. The sun is an abundant and practically infinite source of energy, so researchers around the world are racing to create novel approaches to "harvest" clean energy from the sun or transfer that energy to other sources.
This week in the journal Applied Physics Letters, from AIP Publishing, researchers from the University of Waterloo in Canada report a novel design for electromagnetic energy harvesting based on the "full absorption concept." This involves the use of metamaterials that can be tailored to produce media that neither reflects nor transmits any power—enabling full absorption of incident waves at a specific range of frequencies and polarizations.
"The growing demand for electrical energy around the globe is the main factor driving our research," said Thamer Almoneef, a Ph.D. student. "More than 80 percent of our energy today comes from burning fossil fuels, which is both harmful to our environment and unsustainable as well. In our group, we're trying to help solve the energy crisis by improving the efficiency of electromagnetic energy-harvesting systems."
Since the inception of collecting and harvesting electromagnetic energy, classical dipole patch antennas have been used. "Now, our technology introduces 'metasurfaces' that are much better energy collectors than classical antennas," explained Omar M. Ramahi, professor of electrical and computer engineering.
Metasurfaces are formed by etching the surface of a material with an elegant pattern of periodic shapes. The particular dimensions of these patterns and their proximity to each other can be tuned to provide "near-unity" energy absorption. This energy is then channeled to a load through a conducting path that connects the metasurface to a ground plane.
The key significance of the researchers' work is that it demonstrates for the first time that it's possible to collect essentially all of the electromagnetic energy that falls onto a surface.
"Conventional antennas can channel electromagnetic energy to a load—but at much lower energy absorption efficiency levels," said Ramahi. "We can also channel the absorbed energy into a load, rather than having the energy dissipate in the material as was done in previous works."
As you can imagine, this work has a broad range of applications. Among the most important is space solar power, an emerging critical technology that can significantly help to address energy shortages. It converts solar rays into microwaves—using conventional photovoltaic solar panels—and then beams the microwave's energy to microwave collector farms at designated locations on Earth. Japan is way out in front of rest of the world in this realm, with plans to begin harvesting solar power from space by 2030.
"Our research enables significantly higher energy absorption than classical antennas," Ramahi said. "This results in a significant reduction of the energy harvesting surface footprint. Real estate is a precious commodity for energy absorption—whether it's wind, hydro, solar or electromagnetic energy."
Other key applications include "wireless power transfer—directly adaptable to power remote devices such as RFID devices and tags or even remote devices in general," Ramahi noted.
The technology can also be extended to the infrared and visible spectra. "We've already extended our work into the infrared frequency regime and we hope to report very soon about near-unity absorption in those higher-frequency regimes," added Ramahi.
Explore further:
Video: Solar power from energy-harvesting trees
More information:
"Metamaterial electromagnetic energy harvester with near unity efficiency," by Thamer S. Almoneef and Omar M. Ramahi, Applied Physics Letters on April 14, 2015. DOI: 10.1063/1.4916232
gkam
But a standard antenna is not a big energy producer. We usually set radio signal strength to break squelch at 3 microvolts.
24volts
Liem
It was about gold nanoantennas for infrared harvesting.. the problem at the time was that they could not have fast enought current rectifiers and I don`t think they have solved this problem yet.
adam_russell_9615
1. huge energy resource
2. triggered rain when we want it (remove that energy and water MUST condense)
3. prevent that heat from going directly into the atmosphere adding to global warming.
TheGhostofOtto1923
-Its still not a whole heck of a lot is it? What we need are entirely new sources of energy suitable for both powering robots indefinitely and desalinating enough water to supply california.
And these sources may be just around the corner.
http://www.e-catw...-iccf19/
http://www.blackl...ats-new/
-We had better hope that they are.
gkam
allergg
peter_bilski
Just saying , electromagnetic waves , quite a broad spectrum one may think about. (?)
PPihkala
Those are nice, but they do not compare to what Solar Hydrogen Trends is doing with COP > 900: http://www.solarh...nds.com/ They appear to be fissioning oxygen from water to gain >0.9kg of hydrogen from 1kg of water. At room temperature.
antialias_physorg
From the linked abstract:
A quick google found a 2.54 GHz rectifier with a 60% efficiency.
TheGhostofOtto1923
http://youtu.be/inCC-PAggRA
http://youtu.be/ah5FEpGql9s
gkam
Do you dream of me at night?
ulao
3. prevent that heat from going directly into the atmosphere adding to global warming.
Sorry it doesn't work that way. Once the energy comes in it has to be dumped somewhere as heat unless you can somehow re-radiate back into space.
ulao
ARC-27s. Man you do go back. We used those things in RAPCON in the 60s. They date back to the 40s.
gkam
ulao
gkam
gkam
ulao
ulao
TheGhostofOtto1923
gkam
Pay attention, and you can learn something.
Da Schneib
They got 93% of the power back, minimum, 97% commonly, and it appears they got it through resistors, feeding the power out through vias. Simple wiring, in other words. Maybe other folks were too involved in the surface features and forgot all their electronics.
Da Schneib
contd
Da Schneib
Yep. And with good efficiency in transmission, this is a very viable technology.
gkam
Not me.
Da Schneib
Returners
You'd need collectors on the spot, which means gliders or balloons.
I've mentioned possible uses of balloons to accomplish this as they are more stable than gliders, and there are ways of doing this, I think, without causing too much use of Helium.
You'd want shaped balloons, like zeppelins but flatter instead I think, which have glider-like properties, but make use of bouyancy to maintain the majority of lift They'd carry EM collectors and send back power where needed or ferry people around.
gkam
Let's be honest: A huge grid of PV panels in space with transmitters to send EM radiation down to Earth for power is REALLY dumb.
Energy harvesting on Earth, however is a great idea.
gkam
Sorry to irritate all of you, but what I said is real. Yeah, it is full of ridiculous experience, but true. I was hoping we could discuss it all, the real world, and compare and debate, but too many folk here are playing some kind of game. otto even crows about it, his "sock puppets", and the "games" he plays with others.
But I am here to learn and teach, too. Why are you folk here?
inorg_lsc
The way this is going now, we will enjoy more energy coming from advanced windows than from silicon on roofs, in a few years.
Da Schneib
Why is it every time I come across another antitechnology nutjob, they turn out to be lying about their evidence?
Care to give some sort of reason for being against solar power satellites, Gracie? Afraid we're going to "pollute space?"
gkam
With PV the granularity goes down to the household. With energy harvesting, to the individual.
Da Schneib
Like, actually answering my question, for example?
Let me repeat it: why are you against solar power satellites, Gracie?
BTW, rating all my posts 1 when I'm not doing it to you is pretty transparent, wouldn't you say? So, vicious and vindictive much, Gracie? Just askin'.
Meanwhile, what's a "Research Engineer?" What *kind* of "Research Engineer" is that, precisely, Gracie?
Da Schneib
Maybe you never noticed.
docile
Apr 20, 2015Da Schneib
gkam
"Sock puppets"?
Does he have his hand up your ass?
Da Schneib
Is it really that hard, Gracie?
Keep in mind that the nastier you are, the surer you prove I'm right.
Da Schneib
TechMutualist
I tend to believe that distributed generation is the most likely path forward for mass electricity production, but if the cost can't come down or utilities lobby effectively to keep the grid intact, then this becomes more feasible. I mean, who originally thought that we would have a criss-cross network of copper covering most of the globe?