How to achieve efficient carbon neutral wood heating

[PVGeezer]

There is a longstanding debate about whether wood burning is an environmentally sound practice or not, with many pointing at the fossil fuel based inputs required as a major objection. And as anyone who has relied on wood heat knows firewood is labor intensive no matter how you handle it.

I'm looking to share methods and ideas for selecting, harvesting, transporting, processing, stacking, seasoning, and loading firewood that folks have come up with to keep the both the labor and fossil fuel inputs low and the burns efficient.

I'll start.

I have about 25 acres of which 12 or 13 is mixed hardwoods and pine. I've found that I can harvest 3 to 5 cords annually just from accessible standing dead or windfall trees.

I use an Ego electric chainsaw with an 18 inch bar and have 4 of their larger 7.5AH batteries for it and my other tools. I generally fell, limb, and buck the logs to finished length in the field before hauling them back to the barn for spitting. By the time I run through 3 or 4 batteries I'm ready to take a break. The Ego works pretty well for me but I occasionally wish for a larger saw when I have a big oak or pine to cut. I also have a PTO driven chipper and grind up some of the straighter limbs for use as garde mulch, most of the trash I drag back in the woods to rot.

The hauling is done using my diesel tractor loader, so this is my sole fossil fuel input in the firewood process. Once at the barn I split using a light duty electric/hydraulic splitter, then stack the wood under cover for at least a year of seasoning, preferably two years. I do notice more efficient burning even after a second year in my relatively humid climate, but it's hard to get that far ahead of the game. The little electric splitter gets the job done but I'm interested in exploring getting something faster and less labor intensive, like an electric kinetic splitter or a small firewood processing system.

I have two stoves, one in the house and one in my greenhouse. I tend to burn the pine in the house and the hardwood in the greenhouse. I try to burn both fires pretty hot, no smoldering if I can help it. Both types of wood burn just fine, but I have to shove more pine though to get the same amount of heat as the hardwood so it's easier to use that in the house and reduce my trips to the greenhouse.

I let both stoves go out overnight, relying on the heat pumps in house and heat stored in the greenhouse water storage system while the stoves are cold. I've found I only have to sweep my chimneys once a year and dont ever have more than a little creosote in them.

 

[timselectric]

This probably belongs in chitchat.

 

[JerryK]

by chance are you using a catalytic wood stove? If not those will produce more heat and less emissions up the stack.
I am in Minnesota and that is what we have been using now for over 30 years...
Once hot there is little to no visible smoke coming out of the stack....
Really cool heat waves when it's -10f or colder

 

[DPC]

Yes I agree a modern wood stove will turn your wood onto heat and not into smoke.

 

[PVGeezer]

by chance are you using a catalytic wood stove?

One is a modern low emission high efficiency woodstove that uses secondary combustion rather than a catalytic converter. The one in the greenhouse is an older water stove. About 2/3 of its heat goes into its water jacket which in turn heats a couple thermal storage tanks. The other third heats the air in the greenhouse directly. Water stoves weren't regulated by the EPA so it doesn't have an emissions or efficiency rating. I don't think you can buy a water stove nowadays edit: in the US unless it's also a cook stove.

 

[upnorthandpersonal]

I get all my firewood from my own land, where I'm turning a tree farm (read: mono-culture) into a diverse forest, which means cutting lots and lots of trees that become building material and tons of firewood. The wood is processed with electric tools: chain saw, and splitter, powered by solar (I'm off grid). I use an old McCormick 434 as a tractor to move the logs, but it's fueled with home made diesel, so no fossil fuel use.

Burning the wood is done in two places: the masonry fireplace inside the home, where it is burned at 86% efficiency, and in the gasification boiler with an efficiency of 91%. When both are fired up and you go outside, you don't see any smoke from the chimneys and you don't even smell that wood is being burned.

Trees (now diverse, different species, brush, etc.) grow back and they bring a diverse wildlife both from animals that eat saplings, as well as ground dwelling critters finding shelters in brush piles. Larger animals such as moose can now actually move on that terrain whereas before the trees would be so dense they could not get through.

 

[PVGeezer]

This probably belongs in chitchat.

I think the right place would probably be "Other renewable energy sources". But there is only one subcategory In there right now and its diy wind and hydro. If anyone knows how to create a wood heat category I'm good to move it there.

 

[upnorthandpersonal]

I think the right place would probably be "Other renewable energy sources". But there is only one subcategory In there right now and its diy wind and hydro. If anyone knows how to create a wood heat category I'm good to move it there.

I'll check with Will if we can create that (It'll be some catch all such as 'Other').

 

[DPC]

One is a modern low emission high efficiency woodstove that uses secondary combustion rather than a catalytic converter. The one in the greenhouse is an older water stove. About 2/3 of its heat goes into its water jacket which in turn heats a couple thermal storage tanks. The other third heats the air in the greenhouse directly. Water stoves weren't regulated by the EPA so it doesn't have an emissions or efficiency rating. I don't think you can buy a water stove nowadays edit: in the US unless it's also a cook stove.

Put some fire brick in the water stove.
It will make the fire box a bit smaller but shorter more intense charges will burn cleaner and save you wood too...

 

[DPC]

Burning the wood is done in two places: the masonry fireplace inside the home, where it is burned at 86% efficiency

Could we see your heating systems?

 

[upnorthandpersonal]

Could we see your heating systems?

You already did

Post in thread 'Long term energy storage solutions?'

Dec 7, 2024

Can we see your boiler?

I wrote about it half way through this article:

#6 Heating Systems

In a cold climate, effective and efficient heating systems are paramount. Because I’m off-grid, I also want a heating system that is fail…

medium.com

There is a short on my YT channel where you can see it briefly before I show there is no smoke coming form the chimney:

This is the boiler set-up with the storage tank during the installation process - at this point I'm filling the system with the glycol mixture:



The two connections on the 'right' side of the tank (top and bottom) are where the heatpump is connected. This wah, the heatpump always...

• upnorthandpersonal

• 

 

[PVGeezer]

Put some fire brick in the water stove.
It will make the fire box a bit smaller but shorter more intense charges will burn cleaner and save you wood too...

Interesting idea, although the firebox is a bit small already.

To dig in a bit what is the purpose of the firebrick? To act as an insulator between the water jacket and the fire so the fire burns hotter? If so won't that just increase the ratio of air to water heating?

That I don't really want to do, the greenhouse air is plenty warm enough in the daytime anyway. The stove is backup to a solar thermal collector/radiator on the north wall which is the primary heat source. The purpose of that stove is to store heat in the water tanks during daytime burns on cloudy or very cold days for nighttime release. I don't want to babysit it at night.

 

[PVGeezer]

I get all my firewood from my own land, where I'm turning a tree farm (read: mono-culture) into a diverse forest, which means cutting lots and lots of trees that become building material and tons of firewood. The wood is processed with electric tools: chain saw, and splitter, powered by solar (I'm off grid). I use an old McCormick 434 as a tractor to move the logs, but it's fueled with home made diesel, so no fossil fuel use.

I like that size tractor. I finally threw in the towel on my tired old Ford 2000 diesel (actually a 231 industrial but no one knows what that is) and bought a shiny new Kubota L2501 this year. It does the jobs I need it to do fine but I do miss the heavier machine a bit at times. No emissions controls in the US on sub 25hp diesels yet so I could convert it to biodiesel if I didn't care about the warranty. But how do you keep the biodiesel from solidifying in the winter?

I saw on another (now deleted) post that you use corded electric saws and have one as part of a firewood processor. Can you elaborate a bit on the processor?

 

[upnorthandpersonal]

I moved this discussion to the 'off grid living' forum as I think it fits there as well.

 

[upnorthandpersonal]

But how do you keep the biodiesel from solidifying in the winter?

You can get additives for that, just like with regular diesel.

I saw on another (now deleted) post that you use corded electric saws and have one as part of a firewood processor. Can you elaborate a bit on the processor?

I don't have a 'as part of a firewood processor' machine or something - I just use a Husqvarna 420EL corded chainsaw and an electric splitter. I have a practical set-up where I can stack logs and can cut these in one go (so I can take 5 to 10 logs or something and cut them in pieces in a few cuts) and then it gets moved on the splitter next to it. We can do an entire year's supply of wood like that in a weekend.

 

[PVGeezer]

Ok. I think it applies to on grid folks like me just as well but that's fine.

As long as it's not in chit chat which appears from the 30 seconds I spent there to be nothing but a right wing political cesspool.

 

[DPC]

Interesting idea, although the firebox is a bit small already.

To dig in a bit what is the purpose of the firebrick? To act as an insulator between the water jacket and the fire so the fire burns hotter? If so won't that just increase the ratio of air to water heating?

That I don't really want to do, the greenhouse air is plenty warm enough in the daytime anyway. The stove is backup to a solar thermal collector/radiator on the north wall which is the primary heat source. The purpose of that stove is to store heat in the water tanks during daytime burns on cloudy or very cold days for nighttime release. I don't want to babysit it at night.

The walls of the fire box are cold
The fire brick is not really a good thermal insulator it will still get hot and transfer the the heat but it will let the wood retain more heat and get the temperature up in the fire box
It also act as a moderator keeping hot spots against the steel to a minimum
The fire box will last longer
Less thermal shock to the steel

 

[PVGeezer]

The walls of the fire box are cold
The fire brick is not really a good thermal insulator it will still get hot and transfer the the heat but it will let the wood retain more heat and get the temperature up in the fire box
It also act as a moderator keeping hot spots against the steel to a minimum
The fire box will last longer
Less thermal shock to the steel

Ok so the firebrick is intended to be an insulator otherwise the fire wouldn't get hotter. But not such a good insulator that it won't reduce the heat transfer to the water jacket vs the non jacketed areas? Hmmm. Seems counterintuitive. I'll need to think about that a bit.

This discussion does make me want to try something else though. My pine firewood definitely burns hotter and faster than the hardwood. I've avoided using that in the water stove to save labor loading it. But I might try doing the opposite to see if that improves the water stove efficiency.

It would be pretty easy to be measure as well. All wood being cellulose has about the same thermal content per unit mass. I can simply weigh a days wood supply and compare that to the temperature rise in the water tanks and see if I get a noticeable improvement.

 

[PVGeezer]

You can get additives for that, just like with regular diesel.



I don't have a 'as part of a firewood processor' machine or something - I just use a Husqvarna 420EL corded chainsaw and an electric splitter. I have a practical set-up where I can stack logs and can cut these in one go (so I can take 5 to 10 logs or something and cut them in pieces in a few cuts) and then it gets moved on the splitter next to it. We can do an entire year's supply of wood like that in a weekend.

Wow that's really moving fast, I'm assuming you need several cords at least where you are. What kind of electric splitter? Mine is a low end Chinese one. Works ok but it's kinda slow. Ever looked at the kinetic electric splitters?

 

[upnorthandpersonal]

I'm assuming you need several cords at least where you are.

About three, depending on the winter. In the shoulder seasons, I can use the heat pump since I still make plenty of power but it can be pretty cold.

What kind of electric splitter?

Something like this (it's an inexpensive eastern European one):

Ever looked at the kinetic electric splitters?

No, I don't think I can even get those here. Doesn't look nearly as safe either...

 

[PVGeezer]

No, I don't think I can even get those here. Doesn't look nearly as safe either...

Thanks. The benefit of the kinetic splitters is speed, the flywheels can be storing energy while youre placing the next log in the splitter.

They assure safety by requiring you to have both hands on two separate controls before they will fire. You should wear eye protection too. Just don't have anyone else nearby while you're using one.

What I wonder about is if they'll have enough stored energy to split larger diameter or knotty logs.

 

[PrairieSwamp]

Carbon neutral is tough. Of course it used to be done. But fell, transport, buck, split, stack, transport, etc to support a modern home entirely with human and animal power is not realistic for most. (YouTuber SkillCult used to have a "one cord challenge" where the challenge was to process an entire cord with only an axe. I've never tried it but it's got to be a ton of work.)

I heat mostly exclusively with non-electric stoves in the house (Hearthstone and Vermont Castings.) Have been doing this for 22ish years. My wood lot is almost a 1/2 mile from the house and my Kubota L2800 does the heavy lifting. I have refined my process where I skid entire trees up (minus smaller branches) and process in the meadow. This was driven from necessity - the woods is a swamp, we get so few freezes anymore, and between the day job and being a single dad made woods time scarce. I used to split all the dead Ash exclusively by hand, but the ash is gone and once I got into the Elm a hydraulic splitter was a necessity.

I stay at least 2 years ahead, stack in a single north-south row in the meadow and let the sun and wind beat on it. I keep 5 cords of "this years fuel" in a wood shed so it's ready to go. Properly seasoned wood is absolutely key. I run a Stihl 021 for limbing, and bought a Stihl MS362 for the heavy stuff. I recently bought an Asian clone of a Stihl 066 (kit form) for less than 2 bills and it is an absolute monster. It's heavy but I can't believe how fast it cuts. Starts on the second pull every time.

On average I put 4 cords of well seasoned wood thru the Hearthstone in a season and really only have 1/8" or so of creosote. But my stove is really undersize for a 140 year old farmhouse so I mostly run it hard which cuts down on the creosote.

Most would say it's a lot of work and it is - but I don't want to sit around all winter and watch TV. Plus I'm only taking already dead wood or cleaning ups stuff on other peoples property that they want gone.

 

[455dan]

Thanks. The benefit of the kinetic splitters is speed, the flywheels can be storing energy while youre placing the next log in the splitter.

They assure safety by requiring you to have both hands on two separate controls before they will fire. You should wear eye protection too. Just don't have anyone else nearby while you're using one.

What I wonder about is if they'll have enough stored energy to split larger diameter or knotty logs.

Agreed they can have problems with some tough to split knotty wood . That is where a hydraulic splitter has an advantage , even if it is slower in the wedges movement.

Also agree that it is a good way to stay active and helps a person keep in shape. Tractor fun work as well.

 

[PVGeezer]

Agreed they can have problems with some tough to split knotty wood .

Yeah that was my suspicion. I'd still maybe consider getting a kinetic one to use to quickly split relatively straight grain wood and keep the hydraulic splitter for the knotty stuff. Do you have any personal experience with the kinetics?

 

[455dan]

Yeah that was my suspicion. I'd still maybe consider getting a kinetic one to use to quickly split relatively straight grain wood and keep the hydraulic splitter for the knotty stuff. Do you have any personal experience with the kinetics?

Only reading on TractorByNets threads about them. I have split lots of Pine, Tamarack, Fir, Larch and Birch with the 25 ton hydraulic , even wore out the drive coupling over the last couple decades of use, but I think maybe by now they have hopped up the Kinetics to where maybe the hydraulics have less of an advantage on the tough stuff. Your plan sounds like it will cover all the bases.