3M Novec 7100 and antMiner S7/S9

[unsoindovo]

I looked into this quite a bit back in the S5 days - really, you can pick whatever miner you want, I think everyone who has seen the videos of Novec immediately goes "I WANT THAT!".  I actually went so far as to buy some of it to experiment with a bit, and I had three big takeaways from it... The first is that the actual system in production is much more complicated than it appears.  You aren't just tossing the boards into the Novec, you have to manage how the cables come into the enclosure, and this is surprisingly challenging (and I love acrylic, look at any of the enclosures I've designed in other threads).  The other big enclosure issue is that you still have to have some sort of cold water loop to bring the gas Novec back into it's liquid state - and this leads to my second big takeaway, and that is that you're still left having to deal with the heat.  The best way I found to think of Novec is that it's a REALLY efficient way of transferring heat from one place to another - in this case it's transferring heat from the ASIC to your cold water loop... But the net result is that the water loop now contains the heat.  Sure, dealing with a radiator and being able to convey the heat trapped in water is much more convenient than air.

And then that lets to my final takeaway - part of the system failed at some point in my testing, and the Novec turned to gas and ran away.  All of it.  $1000 basically vaporized overnight, oh, and they took the ASIC with them, since it promptly burned itself up once the Novec took off.  The system itself worked fine for a few weeks, so I wasn't some catastrophic design flaw, but in the end something failed and it was able to escape.  Now keep in mind that I'm in Arizona, so the ambient temps were 100f+, which certainly helped Novec in it's jailbreak - but the real bitch is that I never was able to figure out what failed.  I poured over the enclosure trying to find the leak, but never was successful - and I suspect this is also why in some of the 3M units they actually do some really light pressurization, so they can detect a leak before it's visibly failing.

So for me, the completed system (sealed enclosures, pressurization, water loops, etc) cost so much more than just fans blowing air - and the potential downside of failure being the complete and utter destruction of the system (and Novec, which ironically was the most expensive single component), made this a something not worth pursing - for me at least.  

Hi Mark!!!
i'm really interested to your experience!
did you buy condenser coil or did you do by your self?
If you can share...

thank you for now!

[MarkAz]

i'm really interested to your experience!
did you buy condenser coil or did you do by your self?
If you can share...

No, I didn't use a condenser coil - since this was more experimentation and I was trying to use more easily accessible things I was using a small radiator instead.  While they perform very different functions, the general principle is the same (tube with fins, one to radiate heat the other to collect heat).  I suspect there was some performance loss from the radiator choice but I also figured it was small enough not to matter - as at least in my little test rig it didn't seem to affect it.

Really, very little is different than a normal water-cooling system in that regard - you'll basically pass water through the radiator, then you need to cool it back down in some way.  In my case it was just another radiator with fans I had outside of the Novec enclosure.  Just a closed loop with two radiators, a pump and a reservoir - and it was all PC cooling stuff I have from other cooling systems I've done.

[italianMiner72]

i'm really interested to your experience!
did you buy condenser coil or did you do by your self?
If you can share...

No, I didn't use a condenser coil - since this was more experimentation and I was trying to use more easily accessible things I was using a small radiator instead.  While they perform very different functions, the general principle is the same (tube with fins, one to radiate heat the other to collect heat).  I suspect there was some performance loss from the radiator choice but I also figured it was small enough not to matter - as at least in my little test rig it didn't seem to affect it.

Really, very little is different than a normal water-cooling system in that regard - you'll basically pass water through the radiator, then you need to cool it back down in some way.  In my case it was just another radiator with fans I had outside of the Novec enclosure.  Just a closed loop with two radiators, a pump and a reservoir - and it was all PC cooling stuff I have from other cooling systems I've done.

can you share some photos??
or maybe do you have a thread in bitcointalk forum?

[MarkAz]

can you share some photos??
or maybe do you have a thread in bitcointalk forum?

In general I tend not to take any pictures until I'm somewhat satisfied with the build - and like I said, I really didn't get too much time with it until it all evaporated, and that kind of ended that endeavor.

But just so you know that I'm not full of crap, here's some of the other builds I've done:

My individual S5 enclosure:
https://bitcointalk.org/index.php?topic=1086882


My plenum S5 enclosure:
https://bitcointalk.org/index.php?topic=1184272


My updated plenum Avalon A6 enclosure:


My GPU mining enclosure:


As you can see from it all, I make everything out of aluminum extrusion and acrylic - which are basically the two building blocks when working with Novec - so I was excited to use it...

[italianMiner72]

In general I tend not to take any pictures until I'm somewhat satisfied with the build - and like I said, I really didn't get too much time with it until it all evaporated, and that kind of ended that endeavor.

But just so you know that I'm not full of crap, here's some of the other builds I've done:

wow!!!
thats look really great!!!
it looks very clean and all in to an accurate structure!!!

32 S5 mean about 18,8Kw

 

wich kind of electricity contract do you have???
here 1 Kwatt/Hour cost 0,25euro cents...

what about your contract?

[MarkAz]

wow!!!
thats look really great!!!
it looks very clean and all in to an accurate structure!!!

32 S5 mean about 18,8Kw

 

wich kind of electricity contract do you have???
here 1 Kwatt/Hour cost 0,25euro cents...

what about your contract?

Just because you can only see one rack in the picture, doesn't mean that's all there is...    It was actually only 24 S5's in the horizontal build, the picture of 32 machines is actually Avalon A6's, so each rack was a bit under 40Kw in operation, and you can see the 16 IBM 2880W PSU's that ran up and down both sides.  I wish I took a picture of one of the newer versions of the racks, as I really improved the way the A6's mounted on them - which made maintenance a breeze.  With the old one, if one had to be removed from the middle, you had to remove the ones to the left of it to slide it out.

That's one nice thing about my GPU miner design, it's dead simple to work on, and it only takes 8 screws and the fans are easily removed to work on the back side (if needed).  I actually don't use the support tray in the middle either now that sidehack makes custom cables for me, so that's gone also in the new ones.

[italianMiner72]

But i don't understand how many dollars per kilowatt do you Pay...
Can i know??

[MarkAz]

But i don't understand how many dollars per kilowatt do you Pay...
Can i know??

Sure, Arizona isn't bad, but it isn't the best either - the blended yearly rate is basically right around $0.07...

[bhairavah]

this is just an ideea, but i think it's deserving:

one does not need ONE liquid to do the cooling. one can MIX 2 liquids. maybe 3, even.
oils are soluble in oils. the thicker will act as a condenser, in its whole mass, and the lighter, lower boiling point oil, will fractionally distill. then it will condense in the mass of the thicker, heavier oil.

one only needs to pay attention to combustibility and dielectric constant.

other than that, i'm sure we can hack a dyi-in-your-kitchen solution, once all the chemists get their focus on this.

brainstorm away ?

LE: maybe best moved on a topic of its own ? immersion fluid diy cooking ? req for help from fellow chemistry forums ?