so now what !!!! glycol or no glycol??

[drmiller100]

a quick google search of propylene glycol freezing temperature reveals

http://www.engineeringtoolbox.com/propylene-glycol-d_363.html

how cold does it get there?

around here, i'd sure be looking for at least 50 percent. cost differential from 30 percent to 50 percent is not much, and difference in freezing is huge.

i've seen ethylene glycol when it is freezing. it makes a slushy long before it freezes solid. the slushy in general keeps things from breaking, but for sure don't allow it to flow or be pumped.

 

[jhellwig]

Back in the old days (real old days, anyway), it was common to use alcohol/water mixes in automotive engines for antifreeze. You don't need a real high percentage to act as an antifreeze, an the azeotrope with water is stable enough you have a hard time boiling it off. .

In a closed system like a car radiator that would work. In an open system all you are going to do it boil the alcohol out and loose lots of heat in the process.

 

[habanero]

In a closed system like a car radiator that would work. In an open system all you are going to do it boil the alcohol out and loose lots of heat in the process.

You won't loose as much alcohol as you think. Alcohol forms an azeotrope with water that raises it's boiling point considerably. That's why it is really hard to distill absolute ethanol, because you can only get up to about 95% purity before you start boiling the water off too. I don't know off the top of my head what percentage would be stable at normal boiler operating temps, but I'd guess it to be high enough to depress the freezing point enough for the task at hand. If you wanted to get fancy, just put a condenser on your vent and you'd never lose the alcohol-it'd just condense and could be put back into solution.

But like I said, this is all really a mute point as it would be smarter in the long run to use glycol-based antifreeze anyway.

 

[ghitch75]

put glycol in one for a guy last year and this year we took it out....he couldn't keep enough wood in it!!!!!.....you think they eat wood with just water put some glycol in it and your saw won't ever stop!!!!!!!!

and as far as freezing if your backup heat is setup right(2 T-stats) it won't freeze

hard to freeze 70 degree water