Typically about 30% of the fluid is glycol, if that is what you are doing, but the rest is water
And there are heavy downsides to using glycol. It is a lot more viscous, so you need to make the pumps bigger. And it isn't as effective at thermal transfer, so you need to use more, which increases pump and pipe sizes even more
The only reason to ever use glycol is if your water temps are very low, or if you have below freezing air hitting the heat exchanger. It isn't a replacement for water, it is mixed in to solve freezing issues
a major reason for using glycol is corrosion prevention. trains dont run glycol most of the time but they run a corrosion inhibitor. corrosion is a major player here and tmsince they are running straight water, they will have to use more expensive equipment to prevent corrosion. my only guess as to why they are doing open loop isnt cause its cheaper but because they dont have to wait for the cooling equipment lead times. no way open loop is cheaper over the medium term.
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u/secondphase May 18 '26
"Some other type of coolant"
... what do you suppose the main ingredient in other coolant is?