Wood heating pros and cons

Daox · 01-23-14, 11:22 AM

I got an email from HomePower today and this was one of the links in it. I love the idea of growing my own heat in my back yard. Anyway, its worth a read:

Efficient Heating with Wood | Home Power Magazine

Quote:

Wood straddles the line between being a renewable and a fossil fuel. It is a store of solar energy and atmospheric carbon that can be consumed at a pace similar to the rate at which it is produced—in which case it is renewable. Or it can be burned more quickly, acting more like a fossil fuel. Unlike with vehicles or other complex energy systems, pollution from wood heat remains largely unregulated, and there’s a high potential for misuse. That’s reason to become better informed about the technology and how—and when—to use it most efficiently.

...

So when is heating with wood an appropriate solution, both economically and environmentally? Five factors come into play:
- Ability to obtain local, sustainably produced fuel (firewood or pellets)
- Room for storage and/or drying firewood
- No atmospheric inversion problems
- Low population density
- Ability to source and install a high-efficiency wood- or biomass-burning heater

NeilBlanchard · 01-24-14, 08:53 AM

The main problem with pellets is the very fine ash dust inside the stove. Another problem is the plastic bags and water seepage. I have see a system with a 5 ton storage hopper that can be filled with a vacuum, but the furnace (which is for a radiant floor system) still has to be manually cleaned out.

My family heated with wood for several years when I was in high school. A small (1100sq ft) cape house took ~3.5 cords of mostly apple and maple. That required a good size shed and a lot of hauling. The land my parents owned was ~14 acres that was an old apple orchard; with approximately 150 Baldwin trees and all sorts of volunteer trees. There were 5 of us with strong backs, and we did it with a chainsaw and splitting maul and a large Gardenway cart, a homemade trailer for the family Volvo.

The chimney needed cleaning and I'm sure the soot was there, but not too bad. The chimney was a triple insulated metal 8" flue with an straight vertical run of ~18'-20'.

stevehull · 01-24-14, 11:33 AM

Wood heat is lovely, the sounds of the crackling fire just so nice. But not so the other heat it takes . . . hauling it in and cleaning it out.

For many years we heated with wood (Michigan) and we used efficient airtight stoves (Vermont Castings). But compared to our geothermal heat pump; it just does not compare.

I do have a backup pellet stove, in the fireplace, for emergency heat and the use of pellets is FAR better than chunks of wood.

But thinking about it, all that splitting of wood, decades ago, probably prevented me from killing someone. Splitting wood, when it is about zero, jacket off, is very rewarding as the frozen wood just cleaves apart. Great exercise, good for the mind.

Wood when burned, is still a huge contributor to CO2 and the EPA has recently announced yet another hike in woodstove mandated efficiency.

Steve
conflicted as I love burning wood, but also realize the problems

AC_Hacker · 01-24-14, 12:17 PM

Quote:

Originally Posted by stevehull

...Wood when burned, is still a huge contributor to CO2...

In the grand scheme of things, wood burning is as CO2 neutral as the natural decay of organic material in a forest.

-AC

mrd · 01-26-14, 04:17 PM

Hydro to Heat Converter - Panoramic

I'd buy this bad boy if I could afford it. This is the only hydronic fireplace I've found available in the US. There are tons of European makes.

Hook it up to a buffer tank, with some geothermal/natural gas in tandem. Enjoy the fireplace and save heating costs at the same time.

AC_Hacker · 01-26-14, 06:06 PM

Quote:

Originally Posted by mrd

Hydro to Heat Converter - Panoramic

I'd buy this bad boy if I could afford it. This is the only hydronic fireplace I've found available in the US. There are tons of European makes.

Hook it up to a buffer tank, with some geothermal/natural gas in tandem. Enjoy the fireplace and save heating costs at the same time.

Make one.

-AC

iamgeo · 01-26-14, 07:55 PM

Quote:

Originally Posted by mrd

Hydro to Heat Converter - Panoramic

I'd buy this bad boy if I could afford it. This is the only hydronic fireplace I've found available in the US. There are tons of European makes.

Hook it up to a buffer tank, with some geothermal/natural gas in tandem. Enjoy the fireplace and save heating costs at the same time.

>.................

Acuario · 01-27-14, 02:21 AM

Last summer I installed a combined wood and solar heating system for a client of mine. He bought a second hand hugely overrated wood burner, a boiler rather than a glass fronted nice to have in the lounge burner. He soon discovered it was too powerful for his house.
I added a 1000L buffer storage tank and 4 solar panels to his system. the buffer tank also supplies domestic hot water.

The system works wonderfully. He lights is boiler for a few hours every 2 or 3 days or as needed and it supplies heating and hot water. He has his own supply of wood from olive and carob trees.
https://www.oeg.net/en/tank-in-tank-...ion-g516005400

A couple of important things to be aware of with any wood burner with a back boiler is that you must ensure it has a way to circulate the water to ensure that there is no way the water will boil and that the water tanks don't usually have a very high working pressure so are not really suited to closed systems.

Also they can consume a lot of wood! Sometimes the Kw rating of the burner is given based on burning coal not wood. The wood rating I have seen on some burners is 30% lower than the rating when burning coal.

Acuario

AC_Hacker · 01-27-14, 04:12 PM

Quote:

Originally Posted by Acuario

...I added a 1000L buffer storage tank and 4 solar panels to his system. the buffer tank also supplies domestic hot water.

The system works wonderfully. He lights is boiler for a few hours every 2 or 3 days or as needed and it supplies heating and hot water. He has his own supply of wood from olive and carob trees.
https://www.oeg.net/en/tank-in-tank-...ion-g516005400

Do you know if there is any kind of specification that came with that storage tank that describes the rate of heat loss from the tank?

-AC

Acuario · 01-28-14, 12:41 AM

I'm sure the manufacturer has something but I've not seen it. The tank came with a 15cm thick foam jacket to wrap round it - when I first saw it I thought it was a mattress! There was also a thick foam cap.

The tank is installed in a small purpose built room which also reduces the overall heat loss although energy efficiency wasn't the top priority in this project as the fuel cost is almost nothing.

Acuario

01-24-14, 08:53 AM	#2
NeilBlanchard Journeyman EcoRenovator Join Date: Dec 2009 Location: Maynard, MA Eaarth Posts: 383 Thanks: 78 Thanked 39 Times in 32 Posts	The main problem with pellets is the very fine ash dust inside the stove. Another problem is the plastic bags and water seepage. I have see a system with a 5 ton storage hopper that can be filled with a vacuum, but the furnace (which is for a radiant floor system) still has to be manually cleaned out. My family heated with wood for several years when I was in high school. A small (1100sq ft) cape house took ~3.5 cords of mostly apple and maple. That required a good size shed and a lot of hauling. The land my parents owned was ~14 acres that was an old apple orchard; with approximately 150 Baldwin trees and all sorts of volunteer trees. There were 5 of us with strong backs, and we did it with a chainsaw and splitting maul and a large Gardenway cart, a homemade trailer for the family Volvo. The chimney needed cleaning and I'm sure the soot was there, but not too bad. The chimney was a triple insulated metal 8" flue with an straight vertical run of ~18'-20'. Last edited by NeilBlanchard; 01-24-14 at 08:55 AM..

01-24-14, 11:33 AM	#3
stevehull Steve Hull Join Date: Dec 2012 Location: hilly, tree covered Arcadia, OK USA Posts: 826 Thanks: 241 Thanked 165 Times in 123 Posts	Wood heat is lovely, the sounds of the crackling fire just so nice. But not so the other heat it takes . . . hauling it in and cleaning it out. For many years we heated with wood (Michigan) and we used efficient airtight stoves (Vermont Castings). But compared to our geothermal heat pump; it just does not compare. I do have a backup pellet stove, in the fireplace, for emergency heat and the use of pellets is FAR better than chunks of wood. But thinking about it, all that splitting of wood, decades ago, probably prevented me from killing someone. Splitting wood, when it is about zero, jacket off, is very rewarding as the frozen wood just cleaves apart. Great exercise, good for the mind. Wood when burned, is still a huge contributor to CO2 and the EPA has recently announced yet another hike in woodstove mandated efficiency. Steve conflicted as I love burning wood, but also realize the problems __________________ consulting on geothermal heating/cooling & rational energy use since 1990

01-26-14, 04:17 PM	#5
mrd Apprentice EcoRenovator Join Date: Feb 2010 Location: Milford, DE Posts: 106 Thanks: 5 Thanked 9 Times in 9 Posts	Hydro to Heat Converter - Panoramic I'd buy this bad boy if I could afford it. This is the only hydronic fireplace I've found available in the US. There are tons of European makes. Hook it up to a buffer tank, with some geothermal/natural gas in tandem. Enjoy the fireplace and save heating costs at the same time.

01-27-14, 02:21 AM	#8
Acuario Apprentice EcoRenovator Join Date: May 2011 Location: Tortosa, Spain Posts: 221 Thanks: 2 Thanked 81 Times in 46 Posts	Last summer I installed a combined wood and solar heating system for a client of mine. He bought a second hand hugely overrated wood burner, a boiler rather than a glass fronted nice to have in the lounge burner. He soon discovered it was too powerful for his house. I added a 1000L buffer storage tank and 4 solar panels to his system. the buffer tank also supplies domestic hot water. The system works wonderfully. He lights is boiler for a few hours every 2 or 3 days or as needed and it supplies heating and hot water. He has his own supply of wood from olive and carob trees. https://www.oeg.net/en/tank-in-tank-...ion-g516005400 A couple of important things to be aware of with any wood burner with a back boiler is that you must ensure it has a way to circulate the water to ensure that there is no way the water will boil and that the water tanks don't usually have a very high working pressure so are not really suited to closed systems. Also they can consume a lot of wood! Sometimes the Kw rating of the burner is given based on burning coal not wood. The wood rating I have seen on some burners is 30% lower than the rating when burning coal. Acuario

01-28-14, 12:41 AM	#10
Acuario Apprentice EcoRenovator Join Date: May 2011 Location: Tortosa, Spain Posts: 221 Thanks: 2 Thanked 81 Times in 46 Posts	I'm sure the manufacturer has something but I've not seen it. The tank came with a 15cm thick foam jacket to wrap round it - when I first saw it I thought it was a mattress! There was also a thick foam cap. The tank is installed in a small purpose built room which also reduces the overall heat loss although energy efficiency wasn't the top priority in this project as the fuel cost is almost nothing. Acuario