[Greenbuilding] Al Pex for Solar Heating System

[Bob Korves]

----- Original Message ----- 
From: "Clarke Olsen" <colsen at fairpoint.net>
To: "Bob Korves" <bkorves at winfirst.com>
Cc: <greenbuilding at listserv.repp.org>
Sent: Sunday, January 06, 2008 7:00 AM
Subject: Re: [Greenbuilding] Al Pex for Solar Heating System


>    Isn't it possible that automative hose will last longer in an  enclosed 
> application
>    with no vibration and a narrower temp. fluctuation?
>    Clarke Olsen
>    Spencertown, NY

Yes, it is certainly possible that the black, butyl rubber automotive hoses 
would last longer in a household application.  My biggest worry would be 
about any direct exposure to sunlight, since they are not exposed to direct, 
prolonged sunlight in automotive use.  Maximum temperatures would be lower, 
and they do not get contaminated with motor oil.  Vibration is not a problem 
for automotive hoses anyway -- that is their world!.  Silicone rubber hoses, 
which are usually red, green, or blue in color, are better in almost every 
respect compared to the black butyl ones, except they are softer and if they 
rub against things then they will rapidly wear through unless protected. 
Sometimes, at 500,000 or more mile engine overhauls on big trucks, when 
everything is renewed, the silicone hoses are re-used if they look OK. 
They're that good.

In a glycol filled solar system the price of the glycol and the worry about 
pollution from leakage would certainly send me toward the silicone hoses, 
which should only be needed for short distances anyway.  There are also lots 
of special shapes and many sizes of these hoses made for specific 
applications so things like 30 or 180 degree bends with different inside 
diameters at each end are available.  Heater hose in standard sizes of 1/8 
inch increments from 1/8 inch to 1 1/4 inch inside diameter are available. 
Here is a link to the Gates catalogue.  Goodyear offers a similar line. 
Radiator and heater hoses are what you are looking for.  Custom shapes will 
not be shown in the catalogue.

http://www.gates.com/catalogs/index.cfm?site_section=catalogs&location_id=524

-Bob Korves