Using a 60 Watt incandescent lamp products about 900 lumen brightness(Brightness Meter), and it must dissipate 3 Watt heat via conduction. Using the typical DC LED as light source to reach the same 900 lumen brightness needs 12 LEDs. Suppose that the forward voltage (VF) is 3.2 voltage, current is 350mA, the input power of the lamp can be calculated according to the following formula 1:
Power=12*3.2 voltage*350mA=13.4W……..Formula 1
In this case, about 20% of the input power is converted to light, 80% is converted to heat. It depends on many factors, the fever may be related to the irregular underlying and phonon emission, sealing, material etc. Total amount heat produced by the LED, there are 90% through conducting transmission. Table 1 is for the dissipation of heat from the LED interface, conduction is the main channel for the heat conduction, because convection and radiation only occupy 10% of the total heat transfer. For example, a LED may convert nearly 10.72 W heat (13.4W*0.8). Among them, 9.648W(10.72W*0.9) transfers from the LED interface via conduction.
Table 1 The heat conduction comparion of different light source
|Efficiency||Power Efficiency||Heat comsuption(%)|