Half a croissant, on a plate, with a sign in front of it saying '50c'
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Aerogel Lightbulb

Frosted all over inside
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Use an aerogel to fill the space inside the envelope of the lightbulb. It's insulating, and you get the frosted look too.

The aerogel filling will permit the lamp filament to be run at a higher temperature, increasing efficiency.

The aerogel will, in effect providing micro-cells of convection, reduce evaporation from the filament and thus prolong its life.

The solid part of the aerogel will have to be some refractory material like alumina and the filling some inert gas, maybe krypton for the sake of the advertising tagline.

neelandan, Jun 01 2004

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       It would also reduce the light output of the bulb. Better to buy Compact Flourescents that are efficient, cheap, long lived and even available in daylight colour temperature.
macrumpton, Jun 01 2004
  

       Micro-cells of convection...you do realize there's no convection in a vacuum?
ldischler, Jun 01 2004
  

       Read the last praragraph, ldischler, it is filled with Krypton.   

       And BrauBeaton, raising the temperature is exactly what this idea is on about.
neelandan, Jun 03 2004
  

       I appreciate what you're trying to do, but the primary source of heat transfer is not conduction or convection but through radiation. Perhaps instead of insulation (which will do nothing except provide more chances of converting light into heat, which is not what we want), we can just coat the inside of a light bulb with a material that is reflective in the infra-red spectrum but clear in the visible spectrum.
Worldgineer, Jun 03 2004
  

       //Read the last praragraph//

My point was, there's no convection in an ordinary light bulb.
ldischler, Jun 03 2004
  

       1. You don't want to run the filament at a higher temperature, because this physical limit has already been fully exploited. In short, it would melt.   

       2. It doesn't matter how good an insulator you use, the light bulb would still get hot. Adding an insulator does not change the heat output of the light bulb. It would take longer to reach equilibrium, but the end temperature would be the same.
kinemojo, Feb 18 2007
  

       // 1. You don't want to run the filament at a higher temperature, because this physical limit has already been fully exploited. In short, it would melt. //   

       Halogen bulbs run their filaments at a higher temperature (using the halogen gas to reflect the infrared back to the filament), both refuting your point and making both [neelandan]'s and [Worldgineer]'s ideas unnecessary.   

       // 2. It doesn't matter how good an insulator you use, the light bulb would still get hot. Adding an insulator does not change the heat output of the light bulb. It would take longer to reach equilibrium, but the end temperature would be the same. //   

       The thermal power output will be the same. The temperature difference will not. Why do you wear a coat in the winter if what you say is true?
notexactly, Mar 30 2017
  
      
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