[Strawbale] Sustainability of wood heat.

[Speireag Alden]

On 2008, Feb 16, at 10:54, Sherwood Botsford wrote:

> Steel tubing is hard to bend, and substantially more expensive than  
> (factor of 3) than pvc.
> ABS hadn't occurred to me.  Is it flexible enough to put an 1/8  
> circular arc (45 degree) in 16 feet?

     I don't know, but I suspect that it could be used that way.   
It's reasonably flexible, but all of my actual experience to date is  
with 4-inch schedule 80, and so I can't answer your question directly.

     I can say that the stuff I've used has sat out in the sun for a  
few years with no sign of degradation.

> Pointer to using ABS pipe for structural purposes?

     Haven't got one.  Google on "ABS" and "structural support" or  
"structural strength".

> Greenhouse environments are very humid.  Wood doesn't last long in  
> a warm humid environment.
> A greenhouse frame with wood elements needs to be replaced every  
> few years, or it has to be pressure treated.

     Well, that's why I suggested saplings.  You have a wood lot.   
You can probably cut, annually, far more wood than you actually  
need.  Use durable attachment hardware, like the steel plates or  
steel tubing which they used for geodesic domes.  If you have to swap  
out a few saplings every year, well, cut them to short pieces, set  
them by for two months and you have primo kindling for the next winter.

> I can put up a PVC framed greenhouse in a couple of days, at a cost  
> for frame around 30 cents per square foot of ground covered.
> A viable alternative:
>    Needs to be no more than twice as expensive.
>    Needs to be no more than twice as long to set up.
>
> OR
>
> Convince me that PVC is sufficiently evil, and I'll postpone the  
> greenhouse until I can do something different.


     Well, here's one paper to consider.

     https://www.usgbc.org/Docs/LEED_tsac/PVC/CMPBS%20Original% 
20Submittal.pdf

-Speireag.