Wednesday, March 07, 2012

LED Bulb That is 230% Efficient

You read that right. An MIT research team has shown an LED bulb can actually give off more energy (in light) than it consumes in electricity. Every law about the conservation of energy or thermodynamics that you learned in school just flew out the window. How is this possible?

Well for clarity, lets look at the Gizmodo article:

  • (scientists) from MIT posited that while the bulb's energy requirements decrease at an exponential rate (halving the voltage reduces the input power by a factor of four), the lumen output would decrease linearly (halve the voltage and the lumens drop by half as well). This means that at some point, the amount of lumens the bulb is emitting would be more than the amount of energy spent—essentially "free" light.
Still it's enough to make you head spin!  The factors we do have to watch though are that the bulbs are extremely small and the amount of voltage applied is minuscule.   To get an idea, let's look at the article again:

  • the team was able to generate 69 picowatts of light from just 30 picowatts of energy. (to get an idea of how small a picowatt is,  a picowatt is 1 trillionth of a watt)
But some of the methods used to boost efficiency is equally amazing.  In this instance, the MIT team boosted the bulb's inherent electrical inefficiency by capturing waste heat from the bulb's atomic lattice!  This cools the device and raises the efficiency.   The really good news is that the methods employed can be applied to the LEDs in use today, making them "cold" bulbs.  Though they would not reach the efficiency of  the MIT's bulb, the bulbs would still be giving off light without any waste heat to rob the bulb's overall efficiency. 

Physics online article here


kallamis said...

For hydroponics this would be great. LED's are already the best way to grow any hydroponic plants. You can get the wavelengths you need easily without the heat or energy being used. You can use LED to make a great little under the cupboard hydro herb garden. Fluorescent works, but the LED is the much better way to go, with the only thing in the way, being cost. But they last a long time, and I love having fresh herbs all year.

Beam Me Up said...

excellent point Kallamis!
I myself have not made the jump into led grow lamps, but I do use them in virtually all my light projects now. But the problem for me was when I get into the watt and above bulbs, the major problem is heat. The thought of using a 3 to 5 watt led unit without any or little loss of power and not have to install huge heat sink, is very attractive.