Ecofan - pros and cons?

[jtcedinburgh]

Hi folks.

I read with interest about the EcoFan stovetop fans, and wondered what the consensus is about them. I don't know yet whether I'll benefit from one, and also don't know how tall they are (my stove to blanking plate distance is quite restricted - ~14" I think (will have to measure) so I might not be able to physically locate one atop my stove anyway.

Any comments welcomed, though.

Thanks,

John

 

[Roospike]

Hi folks.

I read with interest about the EcoFan stovetop fans, and wondered what the consensus is about them. I don't know yet whether I'll benefit from one, and also don't know how tall they are (my stove to blanking plate distance is quite restricted - ~14" I think (will have to measure) so I might not be able to physically locate one atop my stove anyway.

Any comments welcomed, though.

Thanks,

John

Well there a "neat" tool. They move "some" air and are quite fun to watch when running. I have bought many as gifts over the years and are a nice different item to give and to get. If you are really needing to move air and that is what you totally have in mind then this fan is not your ticket. You'll want a box fan , ceiling fan , stove blower or other air moving item. If your just wanting a nice little do-dad that does really work ( just not that well for moving real heat ) then its a great little item to have. I have always bought the 3 blade fan and cant say much about the 2 blade unit.

 

[MountainStoveGuy]

Hi folks.

I read with interest about the EcoFan stovetop fans, and wondered what the consensus is about them. I don't know yet whether I'll benefit from one, and also don't know how tall they are (my stove to blanking plate distance is quite restricted - ~14" I think (will have to measure) so I might not be able to physically locate one atop my stove anyway.

Any comments welcomed, though.

Thanks,

John

Eco fans are cool, they gently cirucluate heat away from the stove top. I would say there more of a conversation piece then anything, but, in a small house on solar power, thats the ticket.

 

[webbie]

Does the Law of Conservation of Energy mean anythang to ya?? Or do you believe in perpetual-motion machines??

Hey, Dyl - speak English!

Are you saying that less heat is provided because someone has a fan like this?

If not, what are you saying?

Certainly the fan makes use of energy from the wood - but it seems that, in this case, the energy is "free" because it comes back into the house as heat (friction of the fan shaft, radiation, etc.) - there is really no other place for it to go. Am I missing something?

 

[begreen]

We've had the 3 blade ecofan for 3 years now. Works well, better than expected. This is with 400-600 stovetop temps. It moves the same amount of air as about an 8" muffin fan and is wonderfully silent. In an open floor plan it really does the trick. If you take an incense stick and hold it say 10 feet away, you would be surprised at the amount of air it's moving. We've stopped using corner fans and now only use the ecofan all winter.

This year we've moved the stove and the kitchen is more distant from the heat. It should be the cool area of the house. So far the fan is doing its job well, but it's still in the low 50's. Once we get into serious heating I'll let you know how it is working out with this new layout.

Edit: This is not the ideal solution for stoves that have a top protective grille and/or perhaps soapstone stoves. The fan runs best between 300-600 degrees surface temperature.

 

[jtcedinburgh]

Can I ask how tall your Ecofan is? As I mentioned earlier, I don't have a lot of clearance between the stove-top and the plate above - perhaps 14" max, maybe less?

Edit: I finally found dimensions - the 800 model (the smaller one) is 8.75" tall, and the 802 is 11.5" tall. I suspect that, for good measure, I'd be better off with the smaller one as the larger one is probably too tall.

Second Edit: Will this make much of a difference to my situation, with the stove in a recess?

 

[begreen]

I had to wait until I was home to measure. Our 802 fan is 10 5/8" tall when cool. Maybe the 11.5" is when it is hot? If you have 14" clear it will work fine. I would go for the larger fan for the additional cfm. The fan should work fine in a recessed spot. What are the normal temperatures on the Morso's stovetop?

The next time I have a fire I will do a candle flame and incense stick test to see how far away from the stove the air is moving strongly. I did this last year and was pretty impressed but didn't actually measure the distance.

 

[jjbaer]

Does the Law of Conservation of Energy mean anythang to ya?? Or do you believe in perpetual-motion machines??

Hey, Dyl - speak English!

Are you saying that less heat is provided because someone has a fan like this?

If not, what are you saying?

Certainly the fan makes use of energy from the wood - but it seems that, in this case, the energy is "free" because it comes back into the house as heat (friction of the fan shaft, radiation, etc.) - there is really no other place for it to go. Am I missing something?

Web,

Just saw this but better late than never.....now you know why you gave the guy a time-out...... ;-P

Anyway, you're correct......it may "steal" energy that would otherwise go into the room but you're also correct that all energy eventually gets dissapated as heat and it ends up going into the room anyway..........

 

[Harley]

[quote author="BeGreen" date="1158952219"] Our 802 fan is 10 5/8" tall when cool. Maybe the 11.5" is when it is hot?

They "grow" as they heat up?

 

[precaud]

Will this make much of a difference to my situation, with the stove in a recess?

Last weekend I was watching stack temps on my Morso 2110. They're higher than the Quad by 100F - typically 450-500F. There's alot of heat to be had there. So I played around with a couple fan arrangements; a typical box fan at low speed pointing at the stove front (an arrangement I couldn't live with), and a smaller 8" fan placed in the alcove at the back of the stove, facing up. The point is to enhance the natural convection current and force more of it to wash over the pipe. I liked this setup better. The fan I had on hand is pretty noisey so I'm going to put together something at some point, with more fan surface area and lower speed.

 

[homebrewz]

I'm glad this thread got updated. I've been thinking about getting one of these and have been reading the old posts. BeGreen, do you have the 100 or 150 cfm one? I think those are the two main types.

I have a fairly open floor plan on the first floor, but with 9' high ceilings. I was hoping it might better distribute the heat in the room.
I remember reading somewhere that these fans are not supposed to be placed right in the middle of the stove, but rather on a corner? Probably to help the air wash over the top of the stove?

 

[Andre B.]

I remember reading somewhere that these fans are not supposed to be placed right in the middle of the stove, but rather on a corner? Probably to help the air wash over the top of the stove?

No it is more to get some colder air on the unit to prevent over heating damage to the thermoelectric module.
(broken link removed to http://www.ecofan.co.uk/ecofan-manual-wood-stove.pdf)
http://www.ecofan.co.uk/

I had one I was running on the side of the stove instead of the back like show in the manual and the hot air coming out of the step back was too close and it got too hot and the fan now only runs about half speed. So you have to watch where you put them, you want the upper part to get some cooler air from the room.

 

[lnh62]

I haven't used the Ecofan, but do have a small 5 blade Heatwave fan which runs via a Sterling engine principal (http://www.thermalengines.com/). Similar to the Ecofan, it really wants the surface temp to be in the 400F to 600F range. It's not absolutely quiet, as moving air makes noise no matter what, and the mechanism has a slight sound to it as well. It does get going pretty fast, but will have to try that incense test to check the actual air movement. Without question it's fun to watch and a little educational to my kids as it's a sterling engine.

 

[DoubleClutch]

Does the Law of Conservation of Energy mean anythang to ya?? Or do you believe in perpetual-motion machines??

Does the term "heat engine" mean anything to ya?? Or does your car run on the hot air from your mouth?

 

[restorer]

Does the Law of Conservation of Energy mean anythang to ya?? Or do you believe in perpetual-motion machines??

Does the term "heat engine" mean anything to ya?? Or does your car run on the hot air from your mouth?

Double Clutch,
No need to reply to Mr. Dylan, Not many of us ever understood him. Note the past tense he's on Time-Out, permanent I hope.

 

[Rhone]

I thought the reason for placement at the edge, and not the center was because it uses the temperature difference to power the fan. When placed at the edge the stovetop surface is hot and cool air is blowing over the fins creating what it needs to power it. Placing it in the middle, you have a hot surface and it's drawing in hot air over the fins so the temp difference isn't as great and it doesn't work as efficient (if at all). I could be wrong, thought I read that somewhere.

 

[Andre B.]

I thought the reason for placement at the edge, and not the center was because it uses the temperature difference to power the fan. When placed at the edge the stovetop surface is hot and cool air is blowing over the fins creating what it needs to power it. Placing it in the middle, you have a hot surface and it's drawing in hot air over the fins so the temp difference isn't as great and it doesn't work as efficient (if at all). I could be wrong, thought I read that somewhere.

That is true but it can also then get too hot and be damaged. I think the solder in the thermal module melts and migrates to places it should not be.

 

[ckr74]

I'm a master at tinkering. I wonder if a one of these can be built using common materials? Maybe a website on construction? Been curious for awhile. Thanks!

 

[jtcedinburgh]

I have no idea but would be interested in the outcome - the Ecofans are just a little too tall to fit on my stove as the blanking plate is a little low...

 

[duck]

I built one from household tin cans. If you do a web search for "tin can stirling" like this web site (broken link removed to http://www.boydhouse.com/stirling/index.html)
you'll see the various ones. I used a propeller built into the flywheel to make a fan. The problem with tin cans is it is difficult to get a huge temperature differential with the same materials. I had to use a propane torch to get enough heat on the heat side and put ice in the cooling water to get a large enough temperature difference to get mine to work. You also have to be very careful with clearances. If you get it too sloppy, it won't run, too tight friction kills it. It was a fun project and I will probably build another one. But, to sum it up in a nutshell the eco fans are a relatively good deal if you don't already have all the soldering and metal working items on hand, plus you get a fan that will work.

 

[begreen]

I thought the reason for placement at the edge, and not the center was because it uses the temperature difference to power the fan. When placed at the edge the stovetop surface is hot and cool air is blowing over the fins creating what it needs to power it. Placing it in the middle, you have a hot surface and it's drawing in hot air over the fins so the temp difference isn't as great and it doesn't work as efficient (if at all). I could be wrong, thought I read that somewhere.

That is true but it can also then get too hot and be damaged. I think the solder in the thermal module melts and migrates to places it should not be.

FWIW, I have always placed the ecofan in the center-top of the stove. It seems to work just fine there. At first I worried about overheating, etc. but it keeps churning away and has seen frequent forays into the 600 degree range. The temperature differential is created by the cooling fins. When sitting on a hot stovetop, you couldn't touch the base without getting burned, but the top fins are just warm. That's probably a 4-500 degree differential which is plenty to get it spinning fast. When I did the Home-Prest logs test and had too many logs going, I pulled the fan off the stove as it passed 700 degrees. It sounded like a quiet, miniature Cesna. The fan spun for about 5 minutes after being pulled off the stove.

 

[homebrewz]

BeGreen: Do you know the max heat rating? The top of my Defiant Encore frequently gets to 700 for about 10 or 15 minutes and then settles into the 600-650 range.

 

[begreen]

It's supposed to be ok up to 650. 450 to 600 is the normal operating range.