Heatsinks for CFLs?

[alphacat]

My first thought was that this was a dumb question it's so obvious - but after searching around some here and elsewhere perhaps it's not...

Is there any reason why heatsinks for other devices, namely aluminum ones used for computers, couldn't be used as a CFL mount to help control some or all of the heat from, say, a 65w bulb? Anybody tried this?

 

[Deft]

It will still need to be evacuated some how if you are in a small space, I'm currently trying to get away with 150w of CFL in a closet with no ventilation lol, working so far! I do have an extra heat sink just laying around but it wont fit on my arrangement of 24w bulbs lol.

 

[alphacat]

It'll definitely still be evacuated, no doubt, but a lot of the material technology is behind excess equipment heat: the stuff uses a lot of current and has insufficient surface area to dissipate the thermal energy - so you link it to something conductive, like a heatsink with a lot more surface area to hold the same amount of thermal energy.

In fact, I see no reason at all that some kind of modified heatsink or something using the same principle couldn't be applied to cool reservoirs...

 

[Deft]

You could hook up a radiator or oil cooler with a fan on it if you want lol, but dont they sell little chillers?

 

[alphacat]

They do. I've been looking in the wrong places too, because in the Aquarium hobby chillers are fuggin' expensive!

On eBay there are a handful of small electric chillers, starting at $20 - looking at The Dopest's DIY Chiller thread (http://www.icmag.com/ic/showthread.php?t=33123) got me thinking about cannibalizing the coil assembly from something like a small electric watercooler unit or something. There's even a guy there selling a radiator billed as a "Res Chiller"! Funny.

However, I think DIY heat transfer for homegrowers is amazingly underexplored, at least based on what I've seen. Looking at all the Google results for "DIY chiller" now...

 

[Deft]

Could just let it evaporate at a constant level, that would screw up the nute strength though I think. Evaporation and the change from liquid to gas takes a lot of energy out of the remaining water. In the end I think a chiller would be the way to go, could get a fish tank heater and adjust them both so that it never gets out of optimum 02 holding potential (cold water holds more 02 as you fisherman know) in a kind of climate controlled rez. But I dont think the sub 44w CFLs will need any kind of heat sink.. allthough you could use ram heat sinks and those little ones on them lol.

 

[smokeymacpot]

i dont think a heatsink on a cfl would be very effective, because your going to try and cool glass down and your going to struggle to cool every bit of glass.

the only way i can see you having the slightest bit of sucess would be to get a solid cyclinder of alu or copper and insert it into the centre of the bulb and cooling the back part of the glass.

you will have far more success if you point a fan at the bulbs. that could be a big desk fan blowing air over all the bulbs or a single fan stuck to the end of each bulb. the latter would block some light, the glue wouldnt be very effective when it gets warm and there would be lots of wires.

easiest thing is to use a deskfan, which doubles as good ventilation for the plants too.

 

[clowntown]

You're not trying to cool the glass tube down, but instead the ballast. The glass tube puts out very little heat compared to the ballast.

But the heat from the CFLs are not the issue... it's your ventilation (or a lack thereof)! Better ventilate your grow area first. If you're still trying to remove more heat, consider taking the CFL apart and remote-ballasting your CFLs. This will be the most effective way.

 

[smokeymacpot]

You're not trying to cool the glass tube down, but instead the ballast. The glass tube puts out very little heat compared to the ballast.

But the heat from the CFLs are not the issue... it's your ventilation (or a lack thereof)! Better ventilate your grow area first. If you're still trying to remove more heat, consider taking the CFL apart and remote-ballasting your CFLs. This will be the most effective way.

so is it the ballast that transfers the heat to the tubes?? cos i find the tubes will burn you

 

[clowntown]

I've never found that to be the case in my experience, at least on T8, T12, and T4s (CFL).

 

[smokeymacpot]

maybe your 110v lights dont get as hot as our 230v ones ??

mine are 18w non spiral cfls

 

[clowntown]

I don't really have a clue as I'm no electrician, but I would logically guess the voltage doesn't have much to do with it (less amps, right?). I don't know...

Anyways, if the tube is putting out so much heat that it can't be dealt with easily, a "Cool Tube" would definitely work although the glass or other substrate would reduce the intensity of the already low-intensity light source.

 

[alphacat]

Thanks for pipin' in here fellas.

I'm talking about screw-in spiral CFL bulbs, not linear T bulbs: even with ventilation my temperature problems are more involved than just being too hot or too cold - it fluctuates due to the weather in my region, and since this is a pretty small setup it's easy to build up a lot of heat quickly during the daytime when I'm not around. I rely on the heat from the bulbs to actually bring the daytime temps up a bit; the problem is that left on long enough, they'll pass that threshold and just get warmer and warmer, sometimes bringing the ambient temp up to the low 90's and making it impossible to maintain decent RH. My setup is too small to justify expensive climate controls too.

The lighting that I'm using here is a big 65w bulb in a clamp-on fixture (ceramic socket w/ a 10½" aluminum reflector dish). My first thought was to drill a series of holes around the perimeter and put aluminum nuts & bolts pointing outward through the holes to act as heatsinks, but then it occurred to me that I might be able to buy PC heatsinks since they're so friggin' cheap and just bolt 'em on...

 

[HIDEyourBUD]

alfacat - I think you aren't understanding the way that heat works. The CFLs make X amount of heat. Using a heat sink will still cause that X amount of heat to be transferred into your grow box more quickly but will still be the exact same amount of heat. The way you can reduce the heat in your box would be to isolate the light and ballast or just the ballast from your grow cabinet. There are a number of ways to isolate these components. Once you have isolated the inconsistant heat source (lights), you can use a small space heater in the grow cabinet that will keep your ladies the perfect temperature. If you post some pictures of your cabinet, we may be able to give you some suggestions.

Here's some fun to keep you happy!

 

[alphacat]

You're right - I'm mixing up two separate issues, DUH! Thanks for the reality check.

So yeah, this 65w plugged into the reflector gets nice and warm. I think my original line of thought was to have some kind of thermal transferrance all the way out the box, but I got distracted by the reflector itself - thinking that if I could better dissipate that that temps would be better overall - but you're totally correct. It's still the same amount of thermal energy inside the box.

Back to the drawing board... to drawing thermal energy outside the box. If only superconductive tape was cheap!

I'm still finishing off the area and was going to take pics but wanna wait until it's done to spare me (and you) all of the "dude, you need to ____" posts... Heh.