Try DuPont for anti-freeze solutions. They make a wide variety of brine solutions for general HVAC
applications and food process applications. They have useful literature available. Also check out ASHRAE
handbooks, if they are available to you.
I usually specify EG in my designs, even though they are toxic and carry a disposal penalty. Around these
parts, I specify EG for a -30 F condition. It is important to distingiush between the freezing point of
"slush" verses "rock hard" freezing. Designing for "slush" at your design parametrs instead of "rock hard"
freezing reduces the concentration required. Many designers overlook this.
The problem with Prop. glycol is the viscocity and specific heat penalties imposed on pumping when used for
chilled water service. However, PG is commonly used for food process. You may also avoid the double wall heat
exchanger penalty, but I have not researched that recently.
Tom Anderson
Mechanical Systems Design
South Burlington, Vermont
hvac@together.net
__________________________________________________________________
This greenbuilding dialogue is sponsored by Oikos (www.oikos.com)
and Environmental Building News (www.ebuild.com). For instructions
send e-mail to greenbuilding-request@crest.org.
__________________________________________________________________