6 ms·

The electromagnetic radiation still turns to waste heat.

tsimionescu 2y ago
Not necessarily, it can also turn to motion or to electricity or to chemical processes or to other things. For example, if you're using the light bulbs to light plants, it gets turned to sugar, not to heat.
- thanksgiving 2y ago
  I googled LED light efficiency what percentage of electricity becomes heat and looks like only about 20% of the input is wasted as heat? So a 15W LED light would only need 3W of cooling? It feels even more ridiculous when we put the numbers like this... There is no excuse for LED lights to not have adequate cooling or for them to fail because of overheating... > This means that about 80 percent of the electrical energy is converted to light, while 20 percent is lost and converted into other forms of energy such as heat.
  - sharpshadow 2y ago
    Light bulbs are build to break and be replaced, as far as I understand we could have eternal light bulbs but that’s not in the interest of light bulb makers. That same logic might still apply for modern light solutions like LEDs. I have a more expensive LED bar which is build on top of aluminium to disperse the heat. Did you have heard about the Dubai Lamp? It’s basically a very efficient longlife LED which they only sell in UAE.
    - daveguy 2y ago
      The Dubai Lamp is produced by Phillips, and is about 3x more efficient than typical LED bulbs -- normally 9w for 60w equivalent vs 3w. Their rated life is 25,000 hours, which is 2.5x longer than a typical 10,000 hour led. They are damn impressive, but not "forever". https://www.mea.lighting.philips.com/consumer/dubai-lamp https://www.mea.lighting.philips.com/consumer/dubai-lamp
- ainoobler 2y ago
  In the case of computers it turns to waste heat and whatever is radiated away is not usable energy and is essentially waste heat. Computers are basically devices for converting useful energy into waste radiation.
  - tsimionescu 2y ago
    Agreed, in computers all of the input power becomes waste heat. One small exception may be microntollers that use PWM to emit a signal through an antenna, or to drive a motor. I think in that case some of the energy becomes radio waves (which may never be absorbed entirely so they may not become heat) or motion in the motor.
    - thenobsta 2y ago
      'Useful' signal also comes out in the form of photons from the monitor.
      - tsimionescu 2y ago
        Monitors have an external power source, I have never heard of a monitor being powered by signal coming from the CPU or GPU. That is, the control signal coming from the CPU/GPU doesn't become light, it merely helps decide what light a separate circuit might emit.
        deleted 2y ago
        [deleted]
      - ainoobler 2y ago
        That's still radiation which turns to heat.

Not necessarily, it can also turn to motion or to electricity or to chemical processes or to other things. For example, if you're using the light bulbs to light plants, it gets turned to sugar, not to heat.

thanksgiving 2y ago
I googled LED light efficiency what percentage of electricity becomes heat and looks like only about 20% of the input is wasted as heat? So a 15W LED light would only need 3W of cooling? It feels even more ridiculous when we put the numbers like this... There is no excuse for LED lights to not have adequate cooling or for them to fail because of overheating... > This means that about 80 percent of the electrical energy is converted to light, while 20 percent is lost and converted into other forms of energy such as heat.
- sharpshadow 2y ago
  Light bulbs are build to break and be replaced, as far as I understand we could have eternal light bulbs but that’s not in the interest of light bulb makers. That same logic might still apply for modern light solutions like LEDs. I have a more expensive LED bar which is build on top of aluminium to disperse the heat. Did you have heard about the Dubai Lamp? It’s basically a very efficient longlife LED which they only sell in UAE.
  - daveguy 2y ago
    The Dubai Lamp is produced by Phillips, and is about 3x more efficient than typical LED bulbs -- normally 9w for 60w equivalent vs 3w. Their rated life is 25,000 hours, which is 2.5x longer than a typical 10,000 hour led. They are damn impressive, but not "forever". https://www.mea.lighting.philips.com/consumer/dubai-lamp https://www.mea.lighting.philips.com/consumer/dubai-lamp
ainoobler 2y ago
In the case of computers it turns to waste heat and whatever is radiated away is not usable energy and is essentially waste heat. Computers are basically devices for converting useful energy into waste radiation.
- tsimionescu 2y ago
  Agreed, in computers all of the input power becomes waste heat. One small exception may be microntollers that use PWM to emit a signal through an antenna, or to drive a motor. I think in that case some of the energy becomes radio waves (which may never be absorbed entirely so they may not become heat) or motion in the motor.
  - thenobsta 2y ago
    'Useful' signal also comes out in the form of photons from the monitor.
    - tsimionescu 2y ago
      Monitors have an external power source, I have never heard of a monitor being powered by signal coming from the CPU or GPU. That is, the control signal coming from the CPU/GPU doesn't become light, it merely helps decide what light a separate circuit might emit.
      - deleted 2y ago
        [deleted]
    - ainoobler 2y ago
      That's still radiation which turns to heat.