And I could be wrong and this could be from a previous iteration of this “inert” liquid dialectic insulators chemical line from 3M but I believe some of them have at least in the past had a less the ideal toxicity profile or have had issues with the normal and inevitable slow chemical breakdown from ionising and cosmic radiation… producing notably toxic gasses you definitely wouldn’t want slowly building up unmonitored in an enclosed space for the years.

Don’t get me wrong, the Novec line and it’s ancestors and siblings like the stuff that cooled the old Cray supercomputers… are the sort of Chemical wizardry that had chemical engineering on the prospective career list when I was in high school. I just remember seriously investigating using them for a project regardless of the price and coming across some sort of chemical safety red flag. So if anyone knows/recognises what I’m half remembering, feel free to share the details!

We used this stuff for a small pilot project: https://www.engineeredfluids.com/electrocool

Pre-covid we paid roughly $225 for 20 liters, not bulk pricing. Not quite apples to apples as 3M Novec is a 2 phase coolant, we went with single phase.