Insulation of underground pipe [RE-wrenches]

[Travis Creswell, Ozark Solar]

Pardon my ignorance as I have never done a SHW system that required a remote
mount but why do you go to extravagant lengths to keep the pipe water tight?
 I assume that the water pulls the low temp solar heat away pretty quickly? 
I am used to the outdoor wood furnaces common around here and they rarely
even insulate the pipe.  Of course these wood burners are capable of over
100,000 Btu's and the wood is free. I guess folks like the warm trail in the
yard that leads to the furnace.

That leads me to my next question.  The few space heating SHW systems I have
been called to service performed awfully. Some of it was due to poor design
and installation but even if everything was perfect these systems still had
tremendous limitations from what I could tell. I'd would really like to hear
some more about the details of the systems those involved in this discussion
are speaking of.  How many sq. ft panels? Heating degree days for the area's
that they are installed in?  Tied into radiant in floor? etc.  Why are
people buying them?  How much do they cost?

Thanks
Travis Creswell
Ozark Solar




----------
>From: "Jeffrey Wolfe, Global Resources" <global at sover.net>
>To: "'RE-wrenches at topica.com'" <RE-wrenches at topica.com>
>Subject: RE: Insulation of underground pipe [RE-wrenches]
>Date: Thu, Aug 23, 2001, 4:14 PM
>

>Naked foam in the dirt will not last the 20 years that an SDHW system 
>should. Water perks both down and up. There was an industrial buried pipe 
>system available for a long time (Gilsilate) that was made with power, 
>poured into a form around the pipes, and covered with plastic. They almost 
>all failed in less than 10 years. The powder migrated into the soil, the 
>water went everywhere, and the pipes became effectively uninsulated.
>
>Pipes move underground due to thermal forces in the pipes and in the 
>ground. As they move, the ground and the pipes will tear the foam apart. 
>Dirt and rocks will migrate into the foam, although at a slower rate than 
>into the powder.
>
>Field fabbed underground piping just does not keep stuff water tight over 
>the long term. Any idea you can think of has been tried in the field (I've 
>had sales folks try to sell many of them to me...) The only ones that work 
>have a heavy non-metallic outer jacket with either o-ring or plastic fused 
>seals, with solid insulation foamed inside. They are pricey, and even they 
>must be put in just right. Anchor blocks, expansion loops, guides, etc. 
>It's a good design exercise.
>
>For the sizes we're seeing in our jobs, it's a lot easier, cheaper, and 
>less risky to not rely on the jacket as waterproof. If that cannot be done, 
>then don't scrimp, go for a good solid pre-engineered product.
>
>Jeff
>

- - - -
To send a message: RE-wrenches at topica.com

Archive of previous messages: http://www.topica.com/lists/RE-wrenches/

List rules & etiquette: http://www.mrsharkey.com/wrenches/etiquete.htm

Check out participant bios: www.mrsharkey.com/wrenches/index.html

Hosted by Home Power magazine

Moderator: michael.welch at homepower.com

==^================================================================
EASY UNSUBSCRIBE click here: http://topica.com/u/?bz8Qcs.bz9JC9
Or send an email To: RE-wrenches-unsubscribe at topica.com
This email was sent to: michael.welch at homepower.com

T O P I C A -- Register now to manage your mail!
http://www.topica.com/partner/tag02/register
==^================================================================