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Something I've always thought about. Northern Canada we run our wood stoves for ~8 months a year. Temp on the surface of the stove is 200C to 300C. Outside is
by grecy 3y ago
Something I've always thought about.
Northern Canada we run our wood stoves for ~8 months a year. Temp on the surface of the stove is 200C to 300C. Outside is -20C to -40C.
Let's say an average of 200C temp delta across the TEC.
Throw a radiator on the outside of the cabin, use coolant with a tiny pump to circulate. How much power am I going to generate with a square foot (or two) of TECs strapped to the wood stove, using the coolant loop to cool the other side?
It feels like we have such a huge temperature delta we should be able to do something with.
- Loughla 3y agoWouldn't that effectively just suck the heat from your home? I feel like that's not a great use of your stove?
- UI_at_80x24 3y agoHeating with a wood stove doesn't really have a 'medium' setting. You get 100% while it's roaring away, and that slowly diminishes as the fuel burns down. (Yes you can adjust dampers, and air-flow valves to "slow it down"; but that doesn't really work/happen.) I've lived in a home heated by a wood stove for 10 years. You would build-up the stove so it blasts away, goto bed, and by morning there would be enough coals left to start it up again but quite chilly in the house. There is nothing like it. I love it. I don't have the same access my father did to family farms, wood lots, and trees. Today I would look into rocket mass heaters. Spread that heat out and allow it to more slowly heat a house.
- petermcneeley 3y agoThis sounds all very "homesteading". If you automate various components including wood feed you could get a better experience.
- thsksbd 3y agoOr you do what slavs did for century and build a massive mud oven to trap the heat in.
- at_a_remove 3y agoBetter yet, bring back Feolite for ridiculous heat capacity in Calories per gram.
- Loughla 3y agoYes I'm aware. I grew up with a wood stove as a primary source of heat, and hated it. But that doesn't really address my issue. For an ambient wood stove, the heat is pushed through the house from one central spot (the stove). If you use a system to use that heat for power or something else, aren't you just going to cool your home?
- serpix 3y agoThe solution to this is and has been for centuries is to add mass to the stove.
- Retric 3y agoDoing that pumps energy outside your house without heating your house. A better option is to use the temperature differential between the stove and your house. You get less electrical power, however waste energy from both the stove and the device still heats your house effectively making a system over 100% efficient. Ie convert 1% of the stoves energy into electricity which you then use to power a fan. The fan‘s waste heat also heats the room thus you get to use both the utility of the fan (1%) + waste heat from stove (99%) + waste heat from fan (1%) = 101%.
- waterheater 3y agoYou're not going to achieve an over-unity system. Assuming no other losses, you'll be using 100% of heat energy from the stove. The equation is missing a -1% term somewhere.
- Retric 3y agoYou’re allowed to make use of the same energy at different points in time. The 1% used by the fan is the same 1% that’s heating your room. A computer converts 99.9% of the electricity to heat a room just like a space heater. However, you can play video games on the PC while it’s heating your room.
- pishpash 3y agoThat's why all electric heating should be devices that do work or compute. Do not waste the Gibbs free energy of the universe.
- andbberger 3y agothis was the only sane argument for blockchain mining but it was never competitive with heat pumps
- Scoundreller 3y agoDepends how cold it is outside, but yes, heat pumps usually win.
- skyfaller 3y agoTo steelman your proposal, I should mention that Low-Tech Magazine thinks you're on to something, although they suggest putting the panels on the stove inside the cabin: https://solar.lowtechmagazine.com/2020/05/thermoelectric-stoves-ditch-the-solar-panels/ https://solar.lowtechmagazine.com/2020/05/thermoelectric-sto... I disagree with that article for the simple reason that I do not consider burning wood to be sustainable, or healthy for anything with lungs. Wood should be used for long-lasting construction or left alone / carefully nurtured to aid our forests in rebuilding biodiversity. https://www.nytimes.com/interactive/2022/09/07/world/europe/eu-logging-wood-pellets.html https://www.nytimes.com/interactive/2022/09/07/world/europe/... https://www.theguardian.com/commentisfree/2022/dec/27/wood-burning-stove-environment-home-toxins https://www.theguardian.com/commentisfree/2022/dec/27/wood-b... But if you're going to burn wood anyhow, perhaps thermoelectric stoves aren't a terrible way to generate electricity for yourself.
- antisthenes 3y agoMost burned wood is wood unsuitable for construction. No one goes into the woods and cuts down a 200-year oak to burn in their stove. Short lengths, widths, knots, imperfections, wood waste pressed into pellets, etc. Although you do have a point about it being bad for air quality. Especially old stove installations.
- jfoutz 3y agoI thought pellet stoves got hot enough to be pretty clean. Co2, yes, but not much else?
- jonstewart 3y agoIf you run it properly. A good wood stove will run cleanly as well. It’s all about the secondary combustion. An open fireplace will not get hot enough for secondary and be dirty.
- ericbarrett 3y agoResidential pellet stoves sound great but in practice they are not reliable (moving mechanical parts that operate at high temps, electronics poorly shielded from said temps—the manufacturers are pretty shady in my experience), and the cost of fuel varies quite a bit and can be very high. Compare to a wood stove that needs no electricity and can burn just about any combustible solid. Modern wood stoves are pretty efficient, too.
- petermcneeley 3y agoYes there is a massive potential for power generation. Stirling engine would give you the maximum efficiency but maybe not the max power output. https://en.wikipedia.org/wiki/Stirling_engine https://en.wikipedia.org/wiki/Stirling_engine https://www.youtube.com/watch?v=Ge3cerSVEI0 https://www.youtube.com/watch?v=Ge3cerSVEI0
- grecy 3y agoWhen it's -40 often, and you live off grid, no moving parts trumps complexity every time
- thsksbd 3y agoFor the PD to deliver work it would have to transport heat outside. Heat you're burning wood to have inside. Better to store the heat somehow, and have it be slowly released.
- grecy 3y agoHeat we have a massive, massive, massive excess of. It's electricity I want, in the winter, when the sun is only on the solar panels for ~3 hours a day.
- thsksbd 3y agoya, but not enough to overcome PD's limitations. You're better off buying a little steam turbine and generating electricity directly off of the stove. On top of the electricity, you get to keep the heat. Or, better yet, buy a propane tank and a suitably large generac. Then pipe the cooling water into radiators in the house.