Can someone help settle a "debate" between myself and my engineer son.
Said son claims rv antifreeze will freeze at about 7° F and provided attached graph.
I find it hard to swollow.
What say you?
My understanding is that it does freeze but does not expand so there is no damage to the plumbing.
Rich
Put some in your freezer and test it
Put some in your freezer and test it
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I've done that and it does freeze at lower temperatures than you would expect however it freezes into a slush with minimal expansion. I still use the lowest rated anti freeze that I can buy. I also use the propylene glycol and not the ethylene glycol.
I should have said that it freezes at higher temperatures than you would expect. Consistent with the chart in the original post. My bad.
I think we all understood.
The joy of a 50% mixture of water and ethylene or propylene glycol is that it turns into a slush first.
The science of the whole thing is that water's densest point is 4° above the freezing point. This coincides with the point of greatest expansion after that as water cools it keeps shrinking.
From the internet via Mr. Google:
"Water freezes at 0°C (32°F) and pure ethylene freezes at -13°C (8.6°F), but mixtures of the two freeze at lower temperatures. For example, a 50/50 mixture by weight of ethylene glycol and water freezes at -36°C (-33°F)."
"Pure water freezes at 32° F, but a 60% solution of DOWFROST propylene glycol pushes the freezing point down to -60° F. While the freezing point of pure glycol is only -39° F, the synergy between glycol and water results in a much lower freezing point."
Fun fact: Once water reaching freezing temperature, it still has to give up four more degrees of heat before it freezes. The same goes for warming ice, once ice warms to the melting point it sits there and keep soaking up heat for four more degrees before turning back into water.
Something about "latent heat" comes to mind from physics class and naphtha, I do remember that halt in temperature drop or rise.
Yes, latent heat of fusion, know it well from freezing Tuna fish when I was a chief engineer on the tuna boats worked on.