LED lamps may soon be able to go much longer between fixture replacements thanks to a new graphite foam cooling system developed at the US Department of Energy's Oak Ridge National Laboratory (ORNL) in Tennessee. The graphite foam works by passively wicking heat away from the lamp via its lightly-packed, open skeletal structure – and given that a ten-degree decrease in operating temperature can double the lifespan of LED lighting components, the benefits of keeping them cool are clear.
The technology has just been licensed to LED North America, which plans on integrating it into street lights and other municipal, commercial and industrial applications.
Presently, LEDs are cooled through heat sinks, metal blade-like “fins” that increase the surface area (and thus the cooling capacity) of hot electronic devices. ORNL claims that its foam is superior to heat sinks, due to its high thermal conductivity, low weight and easy machinability, which allows for greater design flexibility. Because it’s full of air pockets, a little of it goes a long way, reportedly also making it very cost-efficient.
Due to the fact that lamps using the foam should last longer, LED North America should likewise be able to offer longer warranty periods than its competitors.
“While this technology will reduce temperatures and increase the life of the LED lighting systems, what it will really do is save municipalities millions of dollars every year in replacement fixture costs as well as maintenance,” said ORNL’s James Klett, who developed the foam.
I have observed that running LED\'s at their maximum rated power, uses up a fair amount of power, and they run hot.
Running them at about 70 - 85% of their maximum power, gives only a marginally perceptible drop in illumination and they DO last forever.