Over-unity?

Implementation of science and theory into hardware.

Over-unity?

Postby FM No Static At All » Tue Mar 13, 2012 9:36 pm

From http://www.wired.co.uk/news/archive/2012-03/09/230-percent-efficient-leds

Image

MIT physicists have managed to build a light-emitting diode that has an electrical efficiency of more than 100 percent. You may ask, "Wouldn't that mean it breaks the first law of thermodynamics?" The answer, happily, is no.

The LED produces 69 picowatts of light using 30 picowatts of power, giving it an efficiency of 230 percent. That means it operates above "unity efficiency" -- putting it into a category normally occupied by perpetual motion machines.

However, while MIT's diode puts out more than twice as much energy in photons as it's fed in electrons, it doesn't violate the conservation of energy because it appears to draw in heat energy from its surroundings instead. When it gets more than 100 percent electrically-efficient, it begins to cool down, stealing energy from its environment to convert into more photons.

In slightly more detail, the researchers chose an LED with a small band gap, and applied smaller and smaller voltages. Every time the voltage was halved, the electrical power was reduced by a factor of four, but the light power emitted only dropped by a factor of two. The extra energy came instead from lattice vibrations.


On the same subject from:http://www.physorg.com/news/2012-03-efficiency.html

Image
An LED’s power conversion (wall-plug) efficiency varies inversely with its optical output power. Wall-plug efficiency can exceed 100%, the unity efficiency, at low applied voltages and high temperatures. Image credit: Santhanam, et al. ©2012 American Physical Society

(PhysOrg.com) -- For the first time, researchers have demonstrated that an LED can emit more optical power than the electrical power it consumes. Although scientifically intriguing, the results won’t immediately result in ultra-efficient commercial LEDs since the demonstration works only for LEDs with very low input power that produce very small amounts of light.


In other words, there is no funding available for it from the private sector and the government research funding won't be satisfactory to bring it to the consumer anytime soon.
Fred a.k.a.
FM No Static at All

Fix America - The Patriot Way!
Whenever any form of government becomes destructive of these ends [life, liberty, and the pursuit of happiness] it is the right of the people to alter or abolish it, and to institute new government...
-Thomas Jefferson (The Declaration of Independence)
User avatar
FM No Static At All
Commander
 
Posts: 1183
Joined: Mon Apr 06, 2009 6:55 pm
Location: Ending the reign of terror called the Federal Reserve System

Re: Over-unity?

Postby Fruitbat » Tue May 06, 2014 3:10 pm

You gotta ask, why is there no money for development of this technology?

Presumably if one made a sheet of myriads of these LED devices all side by side and each one as physically small as possible, and bent the sheet into a cylinder to focus the achieved light on some photovotaics in the middle then once you got it bump started you should have a refridgerating tube that provides electricity.

It would be nice if my refridgerator could be made to give a bit of electricity back.. Air conditioning that runs my stereo would be cool too.

And for spacecraft that would be a neat way to get shut of surplus heat which I believe is a problem.

FB.
Empty Vessels (and reverse biased semiconductors) make the most noise.
User avatar
Fruitbat
Petty Officer 1st Class
 
Posts: 130
Joined: Mon May 05, 2014 9:07 pm


Return to Engineering



Who is online

Users browsing this forum: No registered users and 0 guests

cron