Wood stove top fans (heat powered)

[Snobdds]

@CalG
a lot of people do not have any understanding of heat transfer.

You hear a lot of "it's always 72 according to my thermostat, why do I feel cold in the winter!" a: radiation heat transfer to the cold wall surface despite the air temp

better though to describe it as heat transfer instead of just "heat". its about the movement of energy, not just the energy.

@Snobdds

your stove produces heat, and that heat is transferred to your body or wall by different methods including radiation, convection and conduction.

conduction to the air touching it, or the pot of water on top
radiation due to the temperature difference between objects ie: stove side and wall
convection is how we quantify a fluid (air) being warmed by the other 2 and then it moving and being replaced with lower temperature fluid (air) due to its density being reduced.

a wood stove is very good at radiation heat transfer, but its not the only thing happening. it's why it feels so damn good in a room with a hot stove on a cold day. the wall surface in the rest of the house is cold and your body is radiating energy to the walls. in the room with the wood stove and its radiation, the wall surfaces are much warmer, plus you are getting heat input into your body by the temp difference between your skin and the stove, not to mention the convection currents of air around it.

I understand thermal dynamics. Convection requires another source of energy to push radiant heat. Conduction requires the transfer of a heat source to another by the delta between two different conducting bodies.

 

[DIYOrangeDave]

I put mine at the front edge of my stove with my water bath behind it to help distribute the moisture. It is either pushing or pulling the air around it. Where ever you get the best action would be a good starting point.

 

[CalG]

I understand thermal dynamics. Convection requires another source of energy to push radiant heat. Conduction requires the transfer of a heat source to another by the delta between two different conducting bodies.

Convection occurs within a medium based on the CHANGES in DENSITY attributed to TEMPERATURE.

The AIR molecules around your burning wood stove impacts the hot surfaces Caloric heat is transferred to the air molecule BY CONDUCTANCE, causing that molecule to INCREASE it's VELOCITY. The INCREASED VELOCITY requires MORE VOLUME for a given number of air molecules (mostly Nitrogen 2) at a constant PRESSURE.
Thus DECREASING the density of the warm air relative to the cold air that has NOT come in contact with the hot stove surface. Random Collisions of the fast moving molecule with other air molecules can result in conductive heat (energy as velocity?) transfer both ways depending on collision physics.
Lesser density will "float" on greater density, whether air , water or iron.
The Heat Transfer by Convection ignorant will say "heat rises".
Those in the know will say, HOT AIR rises. Hot water rises, hot air balloons rise aloft. Cold air sinks, the cellar is cold, the loft is warm.

Actually, Cream rises, but that IS a different topic.

ETA
I just now put wood in the stove. The ceiling fan is turning overhead,
I put on leather gloves to protect myself from the damaging effects of conductance while exposed to the hot coals.
I could feel the radiant heat of the stove dramatically increase when the glass door was opened. (Glass is essentially opaque to far infra red radiation. !0 micron wavelength is about the human body temp emission.)

Planck's Law​

Planck's Law can be generalized as such: Every object emits radiation at all times and at all wavelengths. If you think about it, this law is pretty hard to wrap your brain around. We know that the sun emits visible light (below left), infrared waves, and ultraviolet waves (below right), but did you know that the sun also emits microwaves, radio waves, and X-rays? OK... you are probably saying, the sun is a big nuclear furnace, so it makes sense that it emits all sorts of electromagnetic radiation. However, Plank's Law states that every object emits over the entire electromagnetic spectrum. That means that you emit radiation at all wavelengths -- so does everything around you!


It's all a matter of degree! ;-)

 

[CalG]

curious aside.

Common water filled "radiators" in our cars and trucks have little mechanism for radiative heat transfer.

In Germany, they are called "COOLERS". Who would have thunk it?

 

[metalbender]

Got one for Christmas one year, out on the heater, works when it's hot, spins, a novelty. Kinda like a science experiment that has no real use but actually does something.

 

[34Willys]

I have one of those given to me from my Mom. They work like the thermocouple in your water heater pilot light system. Instead of voltage/current going through a hold-in coil to keep your pilot light lit, they route it through a dc motor and the hotter the fire, the faster the propeller spins.
We were renting a crappy cold cabin a year ago and the stove was having draft issues. The stove service guy came to house snickering about how the thing doesn't do squat. I said, yes it does. Since there is no window in the door, rather than opening the door and filling the room with smoke to check the fire several times, I know when the propeller slows or stops, it's time to add wood. And, I can see the propeller from most of the living areas.
Patrick

 

[MossRoad]

My wood stove only produces radiant heat. Maybe yours has special crystals or something that defies physics.

Your wood stove produces more than just radiant heat. The air molecules that touch your wood stove are heated through the process of conduction. Direct contact with each other. That causes the air molecules to expand. As they do, they move up and away from the stove, and cooler, denser molecules take their place. That's called convection.

 

[i7win7]

This one doesn't make/use electricity

This Is Mesmerizing

www.bitchute.com

 

[mikester]

My experience has been the fan motor is made with plastic parts that WILL melt and ruin your fan. I now keep my fan on the outside corners (coldest part) of the stove on an angle.

 

[oosik]

My house has exposed beam cathedral ceilings. I have a large paddle fan mounted at the peak - in the living room. It circulates the warm air around the living room and kitchen.

When we had a wood stove( LOPI ) we cooked on its top. Never had any type of fan anywhere near the wood stove.