Comments on: Harvesting Lost Wave Energy From The Air — New Device For Generating Electricity From Wireless Energy Achieves 37% Efficiency

By: Peter Gray

Peter Gray — Wed, 13 Nov 2013 18:52:00 +0000

No, that doesn’t sound good at all, and you don’t need any fancy research to verify it on your own. For example, the world’s loudest air raid siren uses a 180-HP (134 kw) motor to produce 138 dB at 100 feet (ear-shattering at that range, audible miles away). Assuming ALL the input power is converted to sound, none is lost in transit, and 100% is recovered by these harvesting gadgets, they would collect about 10 watts/sq. meter – much less than a decent PV panel. But typical real-world sound energy levels are thousands of times lower than we’d get from that super siren. So forget about it. Not gonna happen.

By: Peter Gray

Peter Gray — Wed, 13 Nov 2013 18:22:00 +0000

I agree! Where are the content cops when we need them? This kind of sloppy reporting, all too common, makes me leery of accepting anything that appears on cleantechnica. An article a few months ago on flying cars was another example of gawdawful tech reporting.

The volts = power error is stunning, but maybe worse is the suggestion that satellite RF signals could be profitably harvested (!?!?). What scale of scientific ignorance can accommodate that? Solar RF flux is orders of magnitude (10^5, 6, 8?) higher than what any satellite can produce, and there’s a good reason we don’t bother trying to harvest the little energy tail of solar radio. Sheesh!

Newsflash, Duke dudes! We already know how to “power a sensor network in a remote location.” It’s a little thing we call solar PV. check it out someday.

By: Corbin Holland

Corbin Holland — Wed, 13 Nov 2013 02:06:00 +0000

Why do you keep calling energy NRG? Most of NRG’s electrical generation comes from fossil fuels. Are you trying to shamelessly advertise for fossil fuels on a clean tech website?

By: JamesWimberley

JamesWimberley — Tue, 12 Nov 2013 23:43:00 +0000

What’s the amount of energy typically available in the form of electromagnetic waves other than light and infrared/ultraviolet? They don’t say and I guess not much. What this will be useful for is energy harvesting. ARM and its ecosystem are working on ultralow-power sensors and processors that can scavenge enough energy from their environment to operate. Not very fast, but who needs a thermometer to be fast? We will be able to get rid of a lot of batteries.

By: sean

sean — Tue, 12 Nov 2013 23:32:00 +0000

only in the direction you are in. even then there will be some passive re-radiation. the amount of power you could pull on one of these things will be tiny..

By: sault

sault — Tue, 12 Nov 2013 22:22:00 +0000

Duke’s statement makes my head hurt…A Volt is neither a unit of energy or power! It is a unit of electrical potential between 2 points. how in the world does Duke University mess this fundamental distinction up? And then they go on to compare this device to a 5V USB port without admitting that a USB connection can move hundreds to thousands of times more current than this “wave harvester”? Maybe thats why they also try to compare it to solar cells even though solar energy again has thousands to millions of times more energy flux than all the wireless signals bouncing around down here on Earth.
Please do a better job in reporting the basic facts. Slip-ups like this only serve to discredit clean energy and embolden its opponents.

By: Matt

Matt — Tue, 12 Nov 2013 15:14:00 +0000

“including vibration and sound energy harvesting” now that application sound goods. But the one to capture WiFi or cell phone signal and convert to NRG is going to reduce the range of those signals. If I extract NRG from the signal, the signal has less strength.