[Greenbuilding] [Strawbale] Sustainability of wood heat.

[Speireag Alden]

On 2008, Jan 31, at 01:02, Sherwood Botsford wrote:

> Speireag Alden wrote:
>>
>>      No.  Burning wood produces particulates and ashes, and most of
>> the time the wood is not harvested sustainably, though in theory it
>> can be.  I would not use wood in an application where you will lose
>> 70-80% of your input.
>
> Oh come now.
>
> Particulates depend on how well you run the stove.  Poison and  
> pollution
> are matters of concentration.  I have 12 neighbors within a 4 mile
> radius.  That's 1 neighbor per 900 acres roughly.
>
> Ashes are fertilizer. (Potassium and phosphorus) One of my spring  
> chores
> is to take the ashes out to the wood lot ans spread them around.
>
> 70-80% is a bit harsh.  Even crummy wood stoves can manage about  
> 60% if
> they have a reasonable tight door.

     All of your points are fine.  Yes, you can minimize  
particulates.  Yes, ashes are fertilizer if you use them properly.   
Yes, you can harvest sustainably (even though most don't).

     In this application, all that is beside the point.  We were  
talking about an AGS system (Annualized Geo-Solar Storage), where  
you're putting energy into the earth around the house to crank up the  
earth's temperature in the hope of getting some back out much later.   
In single-house application, I'm told that you're going to get back  
only 20-30% of the heat you put into the earth.

     That raises the bar.  I could burn a stove as efficiently as  
possible (call it 95%, which I have heard is basically impossible).   
I generate x pollution.  Now, if I use the stove to heat the earth  
around my house, for the same return of heat to the house, I generate  
3x or 4x pollution.

     No good.

     The percentage I named was not stove efficiency.

-Speireag.