Electricity Generation with Wood Heat

[pa_friendly_guy]

Seasons, I have been designing in my head for some time a system exactly like what you are taking about. If you have a 2 story house, with a 2 story chimney you could run 4" pipe starting some where along the bench, bring them in from the front of the bench to draw max air flow, and cobb the whole way up the chimney to increase the mass. Run the 4" pipes up the chimney mass and into the 2nd story. At that point you have the heat where you want it and you could run those duct pipes along a floor joist to any room up stairs that you wanted. You could also run them up the chimney to the ceiling joist and take it across the house to any room down stairs where you needed more heat. I understand that you are dumping the heat up along the ceiling, and heat rises, but you are adding heat to an otherwise cold room. A small fan in each pipe powered by one of Matts units would be a plus, but I think you could get a lot of heat just gravity flow. I think you could use at least 4 pipes along the chimney, more than that and I think you might be robbing too much heat from the chimney and effect the draft. The pipes could be run on top of the bench, along the sides of the bench, anywhere you want really. The idea is similar to running water lines through the bench to steal heat for heating water. Being a Dummy, and having never built a RMH I am SURE it will work. I have found that stupid people are always sure it will work until they try it .

[DevilsBrew]

[pa_friendly_guy]

Didn't you listen to me, I am SURE it will work. Like I said, this plan is in my head, and nowhere else. I am sure it could be tweaked a bit, but I also think it just might work to get heat where you want, or need it inside your home.

[DevilsBrew]

I like how you think. Great plan.

Keep in mind that I always have a million questions. Only looking to learn.

[matt walker]

Seasons, my neighbor does exactly what you describe, using grid powered fans, with his RMH. He swears by it, and I'm convinced it's a good way to get the heat moving around the space. He used 3" dryer ducting for the mass air runs. For sure a TEG could easily run a little fan to push air through those. Guy, I really like your passive idea too. I have dryer ducting built into the bottom of my mass that feeds a vertical space behind the bricks on my hearth, making a passive convective heat exchanger. Pretty much just what you describe, only I don't have a second story so it might be counter-productive, moving heat towards my ceiling.

[4seasons]

I was thinking of running the fans to pull warm air from over and behind the bench and push it out under the bench. I don't have a second story either, I'm just thinking about getting warm air moving out into the room. My current wood stove tends to keep the space around it very warm and the couch across the room warm. But to get the warm air into the kitchen or down the hall to the bedrooms and bathroom I need a fan to get the air moving. I am thinking that by pushing the hot air out low it will create more air flow and better heat distribution.

[pa_friendly_guy]

I would keep the exit to the pipe higher, work with gravity, not against it. Even with a fan pushing it along, work with gravity. You can have the entrance to the duct work low on the front of the bench, exit up higher on the bench with the duct running along the entire length to have as much heat gain as possible. Having a long distance to have the heat move can be a challenge. My neighbor has a small room with an air tight wood stove on the one end of his home, he hooked up a vent in the ceiling of that room and a large round metal duct that he has exiting about 1/2 way into his house next to his stairs to the 2nd floor. When its time to go to bed he goes up stairs and opens a window a crack. I know, that sounds nuts in the cold winter weather, but what he claims happens is that it makes a natural daft and draws the warm air from down stairs to the bed room. He has been doing it for years and swears up and down that it works for him. I feel that a fan is by far the best way to move air. In your situation seasons a fan at the start of the hallway should work. Unfortunately you do have to either trip over it as you try to walk down the hall, or you hit your head on it hanging from the ceiling. Either way is not what you would call ideal.

[pa_friendly_guy]

Matt, I have designed in my head, [ are we starting to see a pattern here? ] a passive system that moves hot air between floors using a chimney. Starting with a basic chimney you brick around it keeping the new brick wall 1 brick away from the chimney. Leave air spaces at the bottom by placing bricks apart leaving plenty of air flow. As you build the new brick wall around the chimney toward the 2nd story you place some dead soldiers back to the old chimney for support. When you hit the second floor you exit the air flow at floor level allowing the air that is heated by the chimney to raise gravity flow from the floor of the 1st floor to the floor of the 2nd floor. Above the floor on the 2nd floor you can brick in the new wall solid to add mass to the chimney to give you a bit more of a flywheel effect. We used to have a hunting cabin with no heat on the 2nd floor, a chimney from the kitchen cook stove ran up through the bed room I slept in and did give off some heat. I designed the brick idea at that time. We never tried it though so it is just a thought in my head.

[matt walker]

I think it would work well Guy. I love it, passive, simple, effective.

[TruGrit]

.. I've never run an RMH, but have run wood stoves for 40 years in all kinds of structures .. usually run a fan behind the heat source .. but, I found very good results by running another fan in the farthest away place, blowing the coldest air back toward the stove ..

.. in my last house (split level) the stove was in the basement, the warm air moved up the stairwell, I put a fan at the top of the stairs, in the basement door, which blew the warm air up through the house .. then when it reached the furthest bedroom, I cut a hole in the floor, installed the same type fan there, which blew the cooler air right down behind the wood stove ..

.. with both fans on low, the air in the house equalized and and only saw a 3 to 5 degree difference in temps throughout the house .. the key I think was both fans pulling and pushing at the same rate ..

.. I will try and set up something like this when I build my RMH this year .. will let ya know how it goes ..