# very quite axial fan, 240v



## dedee (3 Nov 2010)

I have an idea for moving the warm air from my log stove heated leaving room into the hall/stairwell.

I thought I could mount a small axial fan (like wots in computers) into the transom above the door. I have been experimenting with a 120x120 240v fan hung from the door frame but at 37db it is too loud.

Are there any super quite 240v fans equivalent to the Sharkoon Super Eagle ( http://www.sharkoon.com/?q=en/content/silent-eagle-800) which are rated at less than 15db?
If not then how do I go about stepping down the voltage from 240vAC to 12 dc. What is the smallest (physical size) transformer/power supply that I could use to run a 12v fan from a 240v supply?


Or is the whole idea of moving warm air with a very quite computer fan totally bonkers

Cheers

Andy


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## Peter T (3 Nov 2010)

The computer fans can certainly be very quiet. I have a couple in the back of my AV unit to keep everything cool and I had rig an LED to tell me when they were on!

I have used a 12v PSU from Maplins which plugs directly into a remote controlled mains socket.

Alternatively you could use a computer PSU. The lower powered versions are cheap and would allow you to run any number of fans.

Good luck,


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## RogerS (3 Nov 2010)

I googled quiet fan and got this one. Pete's idea re computer power supplies is a good one.


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## dedee (4 Nov 2010)

Roger, I think you forgot to add the link. All of the quietest fans that I found are 12v so I think that is the only way to go.

Peter, the computer PSUs all look way to large. Is this type of plug in PSU to which you refer http://www.maplin.co.uk/Module.aspx?ModuleNo=227631

I think the transom above the door is hollow with plasterboard on either side. So what I envisage is taking a feed from a nearby light switch to a fan control switch which would feed the PSU located inside the transom. The fan will sit one end of a tube with a grill at either end.

Andy


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## RogerS (4 Nov 2010)

Oops..  

http://www.ebuyer.com/product/138586?ut ... m=products

That power supply is more than ample. Do you not have an old similar power supply knocking about anywhere from an old electronic device/game etc?


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## dedee (4 Nov 2010)

Roger, thanks for the link though not as quite as the Shakoon one I linked to above.

Old electronic devices kinda passed me by I'm afraid so will have to buy one.

What do you think of the whole idea of trying to move the warm air from the living room to the hallway and therefore up the stairs as well.

Andy


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## RogerS (4 Nov 2010)

Wouldn't the hot air rise by itself through convection? 

I had been thinking of doing the opposite in the workshop as it has a very high gable and since hot air rises was going to stick a piece of soil pipe vertically with a fan inside it to suck down hot air to floor level.


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## dedee (4 Nov 2010)

RogerS":1zk23vqy said:


> Wouldn't the hot air rise by itself through convection?


yes of course especially if there was no transom above the door. The distance between the top of the door and the ceiling is about 2 feet by moving the warm air trapped close to the ceiling I hope to be able to warm other parts of the house more quickly 

Andy


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## SVB (4 Nov 2010)

Perhaps another variable to consider it the nature of the panel in which is is mounted. At one extreme a piece of 1/4 ply will tend to amplify any noise where as a more substantial panel may dampen any noise?

Just a thought.

S


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## Carlow52 (4 Nov 2010)

If the door is closed, how will you replace the 'moved' air in the room where the stove is?


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## RogerS (4 Nov 2010)

Carlow52":14lfy3is said:


> If the door is closed, how will you replace the 'moved' air in the room where the stove is?



Good question! There's a log burner in the room.


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## dedee (4 Nov 2010)

All of the windows (8) have vents rated at 15 m3 per hour, so I do not think that will be a problem.

SVS good point I'll bear that in mond


Andy


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## Carlow52 (4 Nov 2010)

15 m3 hr in = 15 m3 out somewhere else which is a fair heat loss.

I accept the fan may not create the necessary pressure to push 15m3 / hour out of the room but some form of controlled recirculation might be better


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## RogerS (5 Nov 2010)

Carlow52":qcwuqjxy said:


> 15 m3 hr in = 15 m3 out somewhere else which is a fair heat loss.
> 
> I accept the fan may not create the necessary pressure to push 15m3 / hour out of the room but some form of controlled recirculation might be better



But the fan only shifts less than 1/10 of that figure.


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## FrenchIan (7 Nov 2010)

Dedee, I had the same idea. I asked Ventaxia, and they suggested the following:

45 90 49 LoWatt WCBP 100mm bathroom fan

I've done nothing with the idea so far, so if you go ahead, please let us/me know you get on.

Cheers


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## dedee (7 Nov 2010)

Ian,
very interesting, thanks for the heads up. Very costly though (80 gbp) and I'd would have to by pass the pull cord some how. I'd also have to be convinced about the noise level, rated at 26db. The Sharkoon silent eagle at under 10 quid is rated at 12.4db and I reckon I can get a couple of grills, tube and a psu for another 20 gbp.

I will order the Sharkoon and hook it up under the door frame just to see how quite it is. 
Then I'll make an exploratory hole in the transom to see if it is as hollow as it seems and take it from there

Have you seen anything over here that would do the job? I notice on a few US sites a fan that mounts to the corner of the door frame like this
http://www.amazon.com/SUNCOURT-Doorway- ... B0007N5LHM but they all seem a bit noisy. I also reckon to get warmer air if I fitted a fan closer to the ceiling.

I will let you know how this progresses.

Andy


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## FrenchIan (7 Nov 2010)

I've not looked at locally available kit, as I can always arrange to get what I need from the UK. Nor had I looked at the price. £80 is chunky, but the low noise level is crucial.

I might need the power too, as I'm planning to duct the warm air back down to ground-level after it's taken through the wall - there is (well, will be) a convenient cupboard to hide the ducting - it would be a more efficient use of the warm air.

Good luck.


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## hanser (8 Nov 2010)

Andy 

Why don't you just leave the door into the hallway slightly ajar? Heat will transfer to the hall/stairwell without the need for mechanical assistance.

The benefits: costs you $ugger all, fully adjustable and takes no time.


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## dedee (9 Nov 2010)

Hangar,
when the fire is alight both of the doors into the hall are open wide and yes warm air does eventually finds its way out of the room.
I just thought that if I could force some of the warmest air, which is closest to the ceiling, out of the room the distribution of heat would be quicker.

I've measured the difference in temperature and there is about a 2 degree difference between the ceiling and the top of the door. 

Surely it makes sense to try and move this warmest air quickly around the house?

Andy


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## hanser (9 Nov 2010)

Andy 

I've got a old barn in France and I appreciate what you're trying to do. I don't think a little fan would make a lot of difference and there will always be that humming noise.......... it would drive me mad, however quiet.

If the fan is powerful enough to make a difference you'll end up with draughts/cooler lounge as the warm air at chest height rises to replace the hot air displaced by the fan.

For me, part of the charm of a place in France is the contrast to the 'centrally heated box' I live in for most of the time in the uk. Takes me back to my childhood when there was a stove in the kitchen and the 1 kw bar in the lounge. I can remember some b cold winters.

Bonne chance.

Hanser


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## dedee (10 Nov 2010)

Hanser,
if we were only here for high days and holidays I would be more likely to appreciate the charm.
From what I can gather 12db would probably be less noisy than the fish tank pump(which is on 24-7) or the DVD player which is on most of the time we are in the room.

As we often have to open the windows (even on the coldest nights) when the fire gets going reducing the heat I do not think would be an issue.

Last night for example, 8 degrees outside, 24 degrees at 4 feet up & 3metres diagonally away from the stove, 28 degrees at ceiling height.
Shutters (external) were closed and 2 windows ajar.

Cheers
Andy


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## RogerS (27 Nov 2010)

RogerS":1spxplow said:


> Wouldn't the hot air rise by itself through convection?
> 
> I had been thinking of doing the opposite in the workshop as it has a very high gable and since hot air rises was going to stick a piece of soil pipe vertically with a fan inside it to suck down hot air to floor level.



Got round to measuring the temperature difference between the apex (4.5m high) and head level. Only 1 degree and so don't think it's worth bothering with as I reckon that all the fans, dust extraction etc will churn the air up enough.


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## dedee (29 Nov 2010)

Roger, 
This picture was taken after the stove had been alight for about two hours. The vent on the right chucks out hot air from the chimney breast . a metal flue takes the smoke up and out.
37 degree C, is taken just in front of the plate cloe to the ceiling, 20 degrees is the temperature at the gadget. The other side of the door was 18 degrees 6feet up and about 6 feet away.






Cheers

Andy


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## RogerS (29 Nov 2010)

Ahah..I just re-read my post and realise how easy it was to misconstrue! I was referring to me sticking up my vertical soilpipe with fan to draw down hot air from the apex to my working level in the workshop...


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