LEDs are about 8 times as efficient as incandescent lights. With cost coming down what holds back this highly efficient light source from becoming the main lighting in the world? The answer is heat. Tiny LEDs generate heat which is not radiated in the form of infrared heat like the incandescent bulb does. In order to generate enough light many LEDs are clustered together to generate enough light to form an alternative to light bulbs. As every LED generates a little bit of heat, clustering them together makes it a lot of heat. Traditional ways to get rid of the heat is heatsinks. There is however a problem with heatsink. Doubling the heatsink does not double the cooling capacity of the heatsink. The effectiveness in relation to volume becomes worse as the heatsinks get bigger.

The MarulaLED team has overcome this problem with a novel technique called CoolTube. Instead of conducting the heat through an aluminium PCB towards a heatsink, Cooltubes remove the heat at the front of the printed circuit board. This is the place were it is generated first of all. It is a local cooling technique were every LED is surrounded by tubes placed in a PCB. The LED heats up these tubes and forced air sucked through the pipes removes the heated air. This technique offers some interesting advantages. Now that every LED is cooled the same way, the LED cluster can be scaled up to any size in a two dimensional plane. This was not possible with aluminium heatsink, as this has to increase in a three dimensional space. Also is an aluminium heatsink a global cooler which is less effective in the middle of an LED cluster than on the side causing unwanted temperature gradients.