Inline or exhaust fans?

[Wasserpest]

Rolling around a new idea in my head... To cool lighting fixtures, I have always used regular computer fans, which works exceptionally well. Only drawback is the noise and the need for an opening.

I thought of a different design, basically a bit of plumbing to pull air out of the canopy, via a pipe that leads to a different room (adjacent garage). From there I want to pull the hot air through 3/4 or 1/2" PVC pipe.

Want to do the same thing not only for the canopy, but for the tank air space as well as a way to reduce humidity (and possibly cool the water a bit).

I am stuck trying to find a fan that works that way. There are "inline fans" for various applications, but they are all overkill. Looking for something small and cheap along the lines of computer fans, but with a different design so it can be attached to a pipe. I guess something like a miniature turbine?

Any ideas, sources or links would be welcome.

[hydrophyte]

i had a similar application in mind for an aquarium setup. i did quite a bit of searching with "computer fan" and several other combinations of terms. i remember seeing one that was built like a pancake fan, but a cylinder one inch or so in diameter and several inches long. it had a few fans inside of it.

sorry i don't remember where i saw it.

[Consigliere]

Here is a pic of my setup, which is basically what you are asking about.



Basically a drive cabinet cooling fan (110V) and a 4" inline duct fan you should be able to find anywhere. This is from Princess Auto. Mine eventually has to size down to a 1.5" vinyl line which I exhaust into my dryer vent. This will move a significant amount of air if you keep the pipe size large enough but my system doesn't move a lot of CFM because of the long run of small vinyl.

With the PVC and the inline fan probably cost about $60. The drive cooling fan was a freebie.

[Hoppy]

Several years ago - too many to discuss - when I remodeled my kitchen I had a very long run of 4" pipe to exhaust an oven hood fan, so I searched and found that you can buy "booster" fans that fit typical exhaust ducts. They allow you to get good air flow through longer ducts than is otherwise possible. I think if I wanted to do this I would use ducting sold for kitchen fans, and I think it is all 4 inch diameter, plus I would use one of these fans to either supply all of the "sucking" or to boost the flow through the duct.

Smaller diameter piping or ducting would have to have much higher velocity air flow through it, and would whistle enough to drive you mad! I think.

EDIT: note to self: read the post right above yours first! That photo is just what I had in mind, only I would put more distance between the fans.

[Wasserpest]

Ah thanks so much guys, inline duct fan is the term to look for. It doesn't need to have a lot of CFM, I might have to slow 'em down so I don't create a vacuum in my office. When they start to whistle it might be a sign of overkill...

Will check them out at my next trip to the BORG.

Something like that duct-taped fan might work too... Need to look for some square to large round to small round adapters. Fun in the plastics isle.

[killerproblem]

it's not the BEST thing for it but i've used the dryer vent duct for similar things and you can get "fan adaptors" for computer case fans that allow you to use whatever size fan you like with the duct... i went with a pair of 120mm low noise pc fans and a small wood frame that i stapled the dryer duct to for cooling my old 240gal reef (4X 400w halides) and i just vented them into the atic. frozencpu.com has some good low noise fans with decent cfm ratings...

[causedabigpoop]

Try looking into a boats bilge exhaust fan, they are small and are inline type you are looking for.

[wkndracer]

If you go the marine bilge fan route with a 12VDC/110AC adapter I’d research or test in some way continuous use on one of those. Their designed for intermittent use and it might not handle it.
Might be totally fine doing it but it might also fry the motor and short it out.

[Wasserpest]

Originally Posted by killerproblem

it's not the BEST thing for it but i've used the dryer vent duct for similar things and you can get "fan adaptors" for computer case fans that allow you to use whatever size fan you like with the duct... i went with a pair of 120mm low noise pc fans and a small wood frame that i stapled the dryer duct to for cooling my old 240gal reef (4X 400w halides) and i just vented them into the atic. frozencpu.com has some good low noise fans with decent cfm ratings...

Thank you very much, I think that is what I was looking for: Fan Adapter! Last night I searched around in HD and ended up with a 4" to 3" reducer thing, but I just noticed that 120mm fans are larger than 4", so that won't work.

But a quick google resulted in a bunch of 120mm to 80mm adapters, and the 80mm diameter should be easier to connect to tubing/pipes. So I'll get a few of those.

I have plenty of 120mm fans sitting around, each time there is a sale on Yate Loons or Antec or Enermax superultrawhispersilent fans I have a hard time resisting.

Edit - just found what I was looking for at the 'egg: 80mm to 120mm Fan Adapter.

From some computer builds, I have a couple of case ducts left over, they should perfectly connect to the 80mm side of the adapter, and convert it into some ~3" diameter round opening that I can reduce further. Looks like I won't need duct tape after all!

[Hoppy]

Originally Posted by Wasserpest

Looks like I won't need duct tape after all!

Now you are going too far!

[killerproblem]

[quote=Wasserpest;859046]Thank you very much, I think that is what I was looking for: Fan Adapter!

heh no worries, I dabble in WAY too many hobbies so it's not uncommon for me to find stuff outta one to use in another...

test your thruput at the far end you may need to also have a suction fan there... the smaller you reduce the pipe the higher the back pressure on the fan. usally if you go mutch lower than 40-50% of the total size you'll have very little cfm coming thru the pipe, also every corner will reduce the flow, so make the run as strait as you can...

[sunfire99]

Originally Posted by killerproblem

it's not the BEST thing for it but i've used the dryer vent duct for similar things and you can get "fan adaptors" for computer case fans that allow you to use whatever size fan you like with the duct... i went with a pair of 120mm low noise pc fans and a small wood frame that i stapled the dryer duct to for cooling my old 240gal reef (4X 400w halides) and i just vented them into the atic. frozencpu.com has some good low noise fans with decent cfm ratings...

Just wondering if venting high humidity air into the attic is such a good idea. If done constantly, I'd think you may cause a mold problem. Maybe not, but I read a thread long ago over on Reef Central about such a problem from venting into the attic rather than outside.

[Wasserpest]

Originally Posted by killerproblem

test your thruput at the far end you may need to also have a suction fan there... the smaller you reduce the pipe the higher the back pressure on the fan. usally if you go mutch lower than 40-50% of the total size you'll have very little cfm coming thru the pipe, also every corner will reduce the flow, so make the run as strait as you can...

It would be a very short run anyway, maybe a foot, since the tank will be adjacent to the garage wall. The total diameter will go down a lot, like 3/4" pipe (I still hesitate to drill my house...), but it should still work to cool a canopy or create a tiny bit of airflow to reduce moisture.

Hard to imagine living without the fan noise... but I'll get used to it.

[Hilde]

For what size tank is this for?

You know I have seen plenty of low noise pc fans on Ebay. Cheap for they have sleave bearing.

[Wasserpest]

Originally Posted by Hilde

You know I have seen plenty of low noise pc fans on Ebay. Cheap for they have sleave bearing.

Originally Posted by Wasserpest

I have plenty of 120mm fans sitting around, each time there is a sale on Yate Loons or Antec or Enermax superultrawhispersilent fans I have a hard time resisting.

I know...