OP
Wood stove top fans (heat powered)
- Thread starter CobyRupert
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I don’t understand the mechanics, but they use disimilar metals to generate electricity. I bought mine more as a novelty than to be functional, yet if I hold a piece of paper up 10 feet away I can see that there is a limited amount of air movement.
To answer the OP’s question; mine works better on the back of the stove as it gets hotter. Often it won’t even work on the front 1/2 until the fire gets good and hot. That’s when I move it to the front, and put a pot on to heat water or supper.
To answer the OP’s question; mine works better on the back of the stove as it gets hotter. Often it won’t even work on the front 1/2 until the fire gets good and hot. That’s when I move it to the front, and put a pot on to heat water or supper.
OP
CobyRupert
Super Member
I did buy it as more of a novelty than expecting it to make a difference in heat distribution.
…but a 6”-7” fan spinning at ~2000 rpm has to move some air (depending on blade pitch), right?
I guess my questions are more related to air and fan dynamics, densities, thermal boundaries and how they interact with each other.
I was wondering if airplane pilots might have some similar data?
Energy use vs lift vs rpm vs air temperature kind of stuff…??
…but a 6”-7” fan spinning at ~2000 rpm has to move some air (depending on blade pitch), right?
I guess my questions are more related to air and fan dynamics, densities, thermal boundaries and how they interact with each other.
I was wondering if airplane pilots might have some similar data?
Energy use vs lift vs rpm vs air temperature kind of stuff…??
Doughknob
Veteran Member
OK, you are not joking. So i will help out. Notice i responded to the “radiant heat” part. It is not radiant heat. Fans blow convective heat.
Doughknob
Veteran Member
That type fan needs heat on bottom and cool on top to function.
So hottest spot on stove, while at same time drawing the coolest air through fan is ideal. So - if rear is hot, that is best since cooler air can be drawn through.
Actually those fans could use a design change where an ‘offset’ exists so the base sets on the stove and the top part is slightly behind the base……
So hottest spot on stove, while at same time drawing the coolest air through fan is ideal. So - if rear is hot, that is best since cooler air can be drawn through.
Actually those fans could use a design change where an ‘offset’ exists so the base sets on the stove and the top part is slightly behind the base……
Last edited:
OP
CobyRupert
Super Member
This is why I based on question on stove top being uniform heat temperature. Assume fan motor gets same voltage applied to it no matter where placed on stove.
With equal voltage to motor, fan might SPIN faster pulling and pushing hot un-dense air, (if at front of stove) but will it move as many pounds of air?
Conversely, pulling cold dense air (fan at back) may make fan turn slower, but is it actually moving more pounds of air?
Doughknob
Veteran Member
Sorry, revised my post. But you want the maximum heat differential to get the maximum fan speed. That would be as my revised post says.
density differences in this case are trivial to fan speed.
Snobdds
Elite Member
OK, you are not joking. So i will help out. Notice i responded to the “radiant heat” part. It is not radiant heat. Fans blow convective heat.
what comes off a stove so a fan can move? A stove only can make radiant heat...it takes another energy source to convert it to convective heat.
Go play pong with someone else.
AchingBack
Veteran Member
My stove top is too small to share with a fan. I have a regular fan mounted on the wall above the stove. It does a good job of moving the heat around. I also have a ceiling fan to move heat from the ceiling.
CalG
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A stove produces HEAT Period! Produced as elevated temperatures on the exterior panels of the stove.
How that heat is transported away from the stove surface is a variable.
It could be by radiation. (Deadly Infra Red "Heat Rays ;-)
It could be by Convection. Air currents wafting past the warm stove picking up HEAT and becoming less dense. Rising ever upwards until cooled again through adiabatic mechanisms. ;-)
OR
Heat from the stove could be transported by conductance. Like when you fall against the hot side panel and place your hand between to catch your fall. Burning the skin so badly the top layer sloughs off in a sheet.
But hey! Maybe you have a special wood stove that ONLY makes a never heard of sort of heat called radiator heat.
IDK, I'm guessing.
And if one is curious to better understand the difference between HEAT and temperature, try this.
Heat up your kitchen stove to about 450 degrees F.
Open the oven door and stick your hand in. THAT"S TEMPERATURE you are feeling all over the skin of your hand. (a combination of conductance and radiative heating)
Now, Touch the metal rack with your finger. Feel the burning flesh? THAT"S HEAT! (PURE conductive heat transfer)
convection occurs WITHIN a given medium, Conductance occures between different mediums, radiation doesn't require a medium, only a difference in temperatures between two separate surfaces.
All I know, is the "heat seems to all go upstairs". ;-)