Compact fluorescent enclosed space. Heat issues?

[Nick Zentena]

The tech sheets I've looked at all strongly suggest not using
larger bulbs in an enclosed space. How big is still considered enclosed? I'm
building a light source that will be 12"x12"x18" [maybe a little deeper then
18"]. I'd like to place either a large bulb in the 100+ watt range or
multiple smaller bulbs totally the same wattage. I can vent with fans if
need be. Is there any chance this will work? The bulb will be on an average
of 1 to 2 hours at a time.

Thanks

Nick

 

[Victor Roberts]

The tech sheets I've looked at all strongly suggest not using
larger bulbs in an enclosed space. How big is still considered enclosed? I'm
building a light source that will be 12"x12"x18" [maybe a little deeper then
18"]. I'd like to place either a large bulb in the 100+ watt range or
multiple smaller bulbs totally the same wattage. I can vent with fans if
need be. Is there any chance this will work? The bulb will be on an average
of 1 to 2 hours at a time.

Thanks

Nick

You want to install CFLs rated at 100 watts, or 100 watt "equivalent",
which would be closer to 25 to 30 watts?

I can't tell you if your box is big enough, and in fact there is no
line between "works" and "doesn't work". The life problem is gradual.
Most manufacturers rate their CFLs in free air at 25C. The generally
accepted rule of thumb for electronics is that each 10C rise in
temperature reduces life by 1/2. So, if the ambient in your box is
35C, the life of a CFL with integral ballast will be 1/2 the rated
value. Of the local ambient temperature is 45C, the life would be
closer to 1/4 the rated value. These are approximate numbers are vary
considerably between manufacturers.

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Vic Roberts
http://www.RobertsResearchInc.com
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[Andrew Gabriel]

The tech sheets I've looked at all strongly suggest not using
larger bulbs in an enclosed space. How big is still considered enclosed? I'm
building a light source that will be 12"x12"x18" [maybe a little deeper then
18"]. I'd like to place either a large bulb in the 100+ watt range or
multiple smaller bulbs totally the same wattage. I can vent with fans if
need be. Is there any chance this will work? The bulb will be on an average
of 1 to 2 hours at a time.

The part which is most temperature sensitive is the control gear.
Use a compact fluorescent with remote gear, and put the gear outside
the box. Nowadays, the gear itself barely gets warm -- the problem
it being roasted by the tube.

 

[Nick Zentena]

You want to install CFLs rated at 100 watts, or 100 watt "equivalent",
which would be closer to 25 to 30 watts?

I'm basically trying to replace the old PH302 bulb. So equivalent to
500watts. Give or take a little.

I can't tell you if your box is big enough, and in fact there is no
line between "works" and "doesn't work". The life problem is gradual.
Most manufacturers rate their CFLs in free air at 25C. The generally
accepted rule of thumb for electronics is that each 10C rise in

The room is lucky to hit 20C. So it sounds if I move enough air with a fan
or two then things should be okay.

Thanks
Nick