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Comment by jacques_chester | Hacker News Reader

Can you explain how this is different from fluorinert?

I have no knowledge on this subject, but

- According to wikipedia [0], fluorinert as used in the Cray was a single-phase coolant (no boiling). It needed fluid pumps and chilled water, at high energy cost; this phase-change solution avoids both.

- Wikipedia claims fluorinert has a very long atmospheric lifetime and high global-warming potential. [1] 3M claims this new fluid is destroyed by sunlight [2], and doesn't have the same problems.

[0] https://en.wikipedia.org/wiki/Cray-2#Packed_circuit_boards_a...

[1] https://en.wikipedia.org/wiki/Fluorinert#Toxicity

[2] (PDF) http://multimedia.3m.com/mws/mediawebserver?mwsId=66666UF6EV...

(The "M.J. Molina" in the datasheet is the Nobelist and co-discoverer of the ozone hole)

I am not an expert in the field, but a quick look through the product pages at 3M suggests that the important difference is the boiling point. Novec boils at 49 degrees C, so for cooling electronics the primary mode of heat transfer will be the phase change. Fluorinert seems to boil at higher temperatures, 80 and > 200 degrees for the two variants I looked at.

They seem to be in the same family of products and several of their physical properties are very similar, so maybe they're just variants.

Here's a link to a page which has both families:

http://www.mgchemicals.com/products/cleaners/3m-fluids/

Hopefully cost, fluorinert is vary expensive. Also, with a low boiling point of 49c you should be able to avoid pumps as long as you don't mind the components sitting at 120f.

This should be comparably costly, it's also a perfluoro compound. C2F5-(C=O)-CF(CF3)2

Wouldn't it be pretty toxic (especially if it's a vapour?) In a sealed component in a datacentre that problem doesn't matter, but they're speculating about home use also.

I don't know about that compound being toxic, but there are some splendidly awful fluorine compounds:

http://pipeline.corante.com/archives/2010/02/23/things_i_won...

Though that's completely different, it's an oxidizer.

You have fluorine in your tooth paste. Hell, oxygen can be dangerous, nitrogen is used in a lot of explosives etc etc.

Probably not, C-F bonds are extremely stable, so perfluoro compounds are biologically inert. The datasheet says they made some animal inhale 10% (!) Novec gas for 4 hours without effect.

http://multimedia.3m.com/mws/mediawebserver?mwsId=66666UF6EV...

The idea of liquid breathing diving systems is usually tied to a perfluorocarbon.

It has half-life of 5 days in the atmosphere, so it's not that stable. According to the MSDS it and degrades both when exposed to UV and at high temperature (like those present in a structural fire) into hydrogen fluoride gas, which becomes hydrofluoric acid upon contact with moisture (including biological tissue).

Also you're supposed to dike the area if a major spill occurs, but I'm pretty sure that's just MSDS boilerplate.

No, fluorocarbons in general are very inert, with the astonishing result that they're generally less toxic than water.

The 3M leaflet suggests that you should avoid breathing it, or getting it on your skin or in your eyes, but that you shouldn't be harmed if you ingest it.

I don't know if that's relative to some of the other nastier stuff they sell.

The 3M page seems to show servers dunked in "semi sealed" cabinets of this stuff, which boils, evaporates, cools, and falls back into the tank.

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