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Mine works well but then my (small) burner has a flat top and is in a recess in the wall ~600mm wide, 1m high with the front of the burner level with the wall.  I clearly need to get the air out of that recess and into the room so got a fan a few years ago.  Not sure if it makes any difference to the efficiency but you can clearly feel the hot air being moved into the room.

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I have a fan on my Becton Bunny.... but instead of having it blow warm air away from the stove , I have it drawing cold air towards the pipe. So, I guess , the wrong way round as to what it should be....kind of cooling the flue pipe....So would that improve the thermodynamics of the stove ????

Fire away critics !!?

IMG_0198.jpg

Edited by maria warwick
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1 hour ago, maria warwick said:

I have a fan on my Becton Bunny.... but instead of having it blow warm air away from the stove , I have it drawing cold air towards the pipe. So, I guess , the wrong way round as to what it should be....kind of cooling the flue pipe....So would that improve the thermodynamics of the stove ????

Fire away critics !!?

IMG_0198.jpg

Thats interesting,  I would be interested to know how long the fan motor lasts positioned like that,  looks like its a genuine Ecofan, they suggest not to long,  From an operational point of view the stove is freestanding and in a corner so hot air will just be blown out of the RH side,  cant see that would make much difference to the preferred position on the rear edge of the stove.    No doubt you have tried that,  so what are your conclusions in practise ?.

 

Thanks

 

A

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I am a stove fan.

But unless a fan is drawing HP way beyond what stove thermodynamics can provide, it simply cannot "propel" hot air across a room, the hot air will simply rise, or if the room is small enough, the fan is not needed, if the room is big enough to need a fan, the fan cannot be effective.

Unless 230V powered as per Big J.

I simply cannot understand this fallacious belief.

A heat source will cause convection currents that easily outperform any stove fan.

Like in our old living room, when sitting some 5.0m away from the Morso stove, in front of a large double glazed bay window, I could feel the warm(but cooling, therefore falling, but still warm) air coming down from the ceiling, and unnoticeable to me, carrying the window cold air down with it, that was in a room with slightly higher ceilings too.

So;

I am not a fan of stove fans.

P.S.

Ceiling temps in that room were probably not less than 30 deg C, and almost certainly more, but our bedroom was directly above.

Edited by difflock
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I saw somewhere that it's more efficient to have a (powered) fan positioned to blow cold air into the room with the woodburner. Cold air is denser than hot, so this will shift more air (and hence warmth) around the house than having the fan blowing from warm towards cold... Albeit at a small cost of electricity for the fan.

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4 hours ago, sandspider said:

I saw somewhere that it's more efficient to have a (powered) fan positioned to blow cold air into the room with the woodburner. Cold air is denser than hot, so this will shift more air (and hence warmth) around the house than having the fan blowing from warm towards cold... Albeit at a small cost of electricity for the fan.

It's right that you use less power to move a mass of cold air compared with the same mass of hot air as the power needed is pressure times volume per second, as air increases in volume by 1/273 per degree C the same mass occupies more volume.

 

Hot air rises but as a means of air movement it's not at all an efficient heat engine so it does pay to use a bit of electrical power to move air.

 

It is also well known that having feet colder than head makes one feel colder than if the feet are warmer than the head. This is what makes underfloor heating so appealing, not only can it make use of a lower temperature heat source but it means the whole space can be at a lower temperature and still feel comfortable.

 

This is why I pressed for a redesign of our pellet heaters to blow air at ground level along the floor ( I was not successful). There is a phenomenon (the Coanda affect which Dyson now use in their "bladeless" fans) which describes how a jet of air tries to hug a surface, so if warm air is blown in a thin layer along the floor it hugs the surface for longer before it rises because of its buoyancy.

 

I intend to use this when I bleed a bit of stove heat to my adjacent room and I will be using a mains electric fan to do it (about 50W should do it)

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On 15/11/2018 at 15:40, woodrascal said:

We've got two. In our place they work...

They work by mixing the air, the hot air at ceiling level is forced down to head height and the heat is also projected another 10 or 15 feet.     I let them go out on a sale or return basis,  over 80% stay sold buy they are not for everyone.

 

A

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Like rob my two stoves are fitted snuggly into fireplaces and the fans do a job of getting more air flowing around the stove and out into the room, rather than heating the brickwork around the stove quite so much

 

maria's fan is pulling cold air over it, the motor will be fine.  The instructions say don't put infront of the pipe as that would be trying to pull much armer air then. the result is the cooling fins don't get cooled so well, the temp difference across the teg is less, the teg generates little voltage, the fan spins slowly pulling little cooling air...and the result, as well as a slow and useless fan, is the teg getting too hot and frazzling.  maria's is pulling cool air and blowing it at the pipe, that's fine. 

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