Less heat buildup in reflectored LEDs?

[brightnorm]

Incandescants project more heat out the front and LEDs accumulate more heat in the body, but won't reflectored LEDS (ie McGizmo 5W-Pelican M6) project more heat foward, making for cooler bodies?

Brightnorm

 

[dw_1984]

I think (don't quote me) that the heat from incandescents come from the beam itself while LED's don't "shoot" heat out but is produced in the leads (or slug of Luxeons).

I think there was a post before from a member of the Armed Forces who got back from Iraq (sorry I don't remember his name) that said the mosquitos were attracted to all the incandescents while none were after his LED flashlights. That kind of plays into your heat accumulation idea but I believe that the heat in LEDs are produced from the leads and not the light output.

Can anyone confirm/deny?

Daniel

 

[Tomas]

The heat produced by LEDs is from their inherant internal inefficiency at making light.

The amount of power dissipated WILL equal the amount of power consumed. Most of the power that does not come out as light comes out as heat.

IE: If you put in 1 watt of power and only get out 1/5 watt of light, most of the rest of that watt is dissipated as heat.

White LEDs are more efficient than incandescent lights, but still not as efficient as florescents. Red LEDs are the most efficient ...

 

[brightnorm]

Daniel, that sounds interesting but I would need to understand more about it.

Tomas, isn't the idea that inefficiency results in more heat than light the same for incandescents and LEDs? I'm still not clear on the difference in the way one projects heat and the other contains and conducts it.

Thanks both for your responses.

Brightnorm

 

[dw_1984]

As would I brightnorm. It's still quite fuzzy in my mind.

I'm sure some of the more experienced modders can shed some more light on this topic.

Hope you find what you're looking for,
Daniel

 

[shankus]

There is heat in the light of an incandescent light, because the spectrum contains infrared light.

When you shine a bright light at your face (eyes closed, right?), you can feel the heat on your face. Try the same thing with a 5 watt luxeon, you won't feel anything. The spectrum of the white LED has little or no UV (which is why they don't attract insects so much), or IR.

The heat in an LED is caused from it's resistance to the flow of electrons. Resistance always results in heat.

 

[shankus]

Here is the post from the member returning from Iraq, it is BentHeadTX:
Back from Iraq, lighting favorites and ponderings

 

[McGizmo]

[ QUOTE ]
shankus said:
............
The heat in an LED is caused from it's resistance to the flow of electrons. Resistance always results in heat.

[/ QUOTE ]

I was under the impression that the heat from a LED was the result of photons that don't make it out of the die but are absorbed and the energy is converted to heat. As the efficiency of the LED's improve, gained light will be offset by less heat generated. The LED's are just going to be getting cooler as improvements come about. /ubbthreads/images/graemlins/grin.gif

- Don

 

[Darell]

Cool(er)!

 

[NightStorm]

/ubbthreads/images/graemlins/cool.gif er AND a reduction in operating temperature!! /ubbthreads/images/graemlins/grin.gif

Dan