[Strawbale] Sustainability of wood heat.

[Sherwood Botsford]

Derek Roff wrote:

...Munch

>  Even a 
> clean burning stove produces a fair quantity of oxides of nitrogen 
> (NOx) and other gases, in addition to CO2 and H2O.  NOx compounds are 
> more active greenhouse gases than CO2.  Many sources say that NOx 
> produces 5 times the warming effect as a similar amount of CO2.  NOx 
> compounds also contribute to acid rain.
>   
NOx at city scale usage levels is a problem.  Los Angeles is prime 
example.  NOx at rural levels on non-granitic
soils is probably a benefit.  Granite based soils, such as the Canadian 
Shield area have very little buffer capacity. Many cases the water is 
already at a pH of 5 or so from acidic peat bogs.  Soils with 
significant amounts of limestone, marble, dolomite, sandstone have huge 
buffering capacity for acid rain due to the amount of carbonates. NOx => 
nitrogen fertilizer.
>> 70-80% [waste] is a bit harsh.  Even crummy wood stoves can manage
>> about 60% if they have a reasonable tight door.
>>     
>
> I think Speireag was discussing the energy wasted in heating a 
> greenhouse with wood, rather than the simple efficiency of a wood 
> stove.  As Sherwood said in another post, "Energy efficient and green 
> house are an oxymoron."
>   
Unless it's energy that would otherwise be lost.  Epcor's Genesee power 
plant, 5 miles north of me, drops 3+ gigawatts into the local pond.  In 
our climate that could heat a couple of square miles of greenhouse.  To 
give them credit, they've tried to interest people, but all the good 
uses for that waste heat require a man power supply that isn't available 
locally.  Most greenhouse jobs pay minimum wage to twice min wage.  The 
nearest town is 30 km away, and it has only 500 people.  No one will 
commute for a $12/hour job. Our economy right now has truss maker 
carpenters making $30/hr.
> One last assertion:  PVC has a high environmental cost.  Please avoid 
> it when there is a practical alternative.
>
>   
I'm considering a PVC pipe + PE film greenhouse this summer.  What 
should I be using for the frame instead?