In this grand epic of ours, the interval between Beowulf above and Aethelbald below stretches just outside of a season, maybe five months. Apparently a hundred petahashes later, heat damage and fire-catching mining rigs are still the main problems of Bitcoin mining. Funny how that works, isn't it ?
To perhaps remedy this issue, definitively, here is my humble proposal : fill the fucking warehouses with technological gas, yo!
Specifically : seal up your warehouse, pump it full of Pentafluoroethanei and there you go. Place some compressor units outside to extract the heat, some fans inside to distribute the freezing winds and forget about the entire story.
With this arrangement you can in point of fact run your farm as far below zero as you wish - since the atmosphere is dry you'll never have condensation or ice formation. Simply insulate the outside in as many layers of polyurethane foam as you can bother with, three meters thick or whatever, and freeze that mofo. Not only do electronics work slightly better below zero, but should a compressor unit fail you have enough stored cool in there so the rigs can mine full blast for a few hours while you replace the thing. Never ever ever have any downtime ever again due to heat considerations, no matter what happens.
With this arrangement you can also forget about catching on fire : it simply won't ever happen, as there's no oxygen in there. Even should your datacenter somehow surge to 500 degrees : cut power, wait for a few days for it to cool, whatever melted melted but nothing burned, for absolute certain and ironcladly guaranteed. Look at that picture up top again and tell me this isn't worth something.
Sure, you won't be able to have people derp up and down the corridors, unless you put a lock in and buy them astronaut suits.ii Guess what ? They shouldn't be derping around your miners anyway! And besides, astronaut suits are pretty cool, a lock is not really that expensiveiii and if not you can simply turn off the farm, pump the technological gas into tanks, pump atmospheric gas in there, send the crew in for maintenance, pump air back out, HFC-125 back in and you're ready to roll. With some management the whole thing should be less than six hours. Look at that picture up top again and tell me six hours is a big deal.
And what about costs ? Suppose your warehouse is one hectare (~100k sq ft) in a 4:1 arrangement (200 x 50 meters) with ceilings at 7 m (23 feet, more or less standard). That means your warehouse contains 70k cubic meters of gas maximally. Adding a 5% technological margin (for whatever is in pipes, being compressed, whatever) and a 10% safety margin (so you keep some on the premises just in case you develop a loss, some in transit being shipped in etc etc) the grand total is 80k cubic meters of HFC-125 you could possibly need.
HFC-125 goes for about $3`800 per ton FOB. Since it's a gas, each kmol counts for 22,4 cubic meters, and since its formula is CF3CHF2 each kmol weighs 19 * 5 + 12 * 2 + 1 = 120 kgs. Therefore, the cost of your 80k cubic meters should be no more than 4`000 * 120 / 1`000 * 80`000 / 22.4, or about $1`700`000. Which yes, is more than a cup of coffee, but otherwise comes to about two dollars per sq ft, probably less than your monthly rent!
As a gas HFC-125 has a caloric capacity of about 0.85iv (water is ~4, air is ~1), which means that it heats about 15% faster than air. Your 70k cubic meters will require 850 * 70 * 70000 / 22.4 = 185 MJ to go from -10 to +60 degrees, which means 18kWh per square meter going for a full hour - roughly double what your power density is going to be. Even accounting for gradients is not going to change much (seeing how hot gas will go towards the ceiling, whereas your equipment is on the floor) ; meanwhile you can extract heat at any speed you choose, with that much gas to work with you're really only limited by how much you're willing to spend on compressor and heat exchanging elements. 1 TJ/h or whatever you wish, it's yours.
Polyurethane foam costs about $200 per cubic meter. If you go crazy and insulate 1 meter thick you'll need (50 + 200) * 2 * 7 + 3 * 10000 = 13`500 cubic meters, coming to about $2.5 million. It has a λ10v of about 0.02 (more or less the same as air), which means that one meter's thickness will ensure a total power drain out of your construction of just about 300 Watts, very roughly speaking. Not the worst of your problems.
So to sum it up : for ~2mn for the gas and ~3mn for the insulation, plus maybe 1-2mn more for various trimsvi you'd have 10k sqm of heat-inert floor. < 1k$ per square meter should not be a consideration, seeing how this arrangement will likely exceed the lifetime of your miners, and seeing how you can now pile up at least five meters' height of mining gear, and you can put 1 MWh through each of those square meters of floor without a care in the world. Anything you buy should be doing at least 1Gh/J, which means each sqm should do at least 1Ph, which means that a) your datacenter so equipped should be able to support 10 Yh, roughly 100x total network output currently, and b) your ~$700 or so cost per sqm of flooring amortises in all of... wait for it... o my gawd... 25 BTC per block, $250 per BTC, 1% of total output, one block every 10 minutes... can it be... two hours ?!vii Oh dear!
And guess what : if you're not really planning to deploy 10 Yh, you could just as well scale the foregoing down a bit. A 10 x 10 meter room for a notional 1/100 floor surface would, with ceilings at 2.75, only displace 275 cubic meters, a mere 0.4% of our original 70k. Which means that yes, the ~$700 per sqm will prolly go up, though not likely to 1k, whereas the total cost would go down, though not likely all the way to... $40k ? You mean less than a fucking car, let alone jets and whatnot ?
Seriously people. Stop thinking with your girlfriend. There's absolutely no need to hear about how some schmuck bought himself a twenty foot gilded dildo encrusted with Bohemian lead crystalsviii. There's high need of hearing about some sane miner made the first-ever HCF-125 submerged datacenter.
Get on with it.———
- It's an excellent choice for this application because it's a refrigerant gas so inflammable it actually doubles as a fire supression system. Seriously, if you sprung for the best fire supression money could buy you'd basically have a system that dumps CF3CHF2 installed anyway. And also, having exactly zero ozone depletion factor and being the replacement of choice all over the US for older refrigerants, you can advertise your environment-friendliness with excellent basis in fact (it won't matter for squat, because the envirofreaks are not even slightly fact based, they just hate capital and industry - but that's an entirely different discussion). [↩]
- Mostly so they can continue breathing - otherwise HCF-125 is not toxic nor irritating - it's pretty much copacetic at best. [↩]
- What, two interlocking steel doors and a pump ? O noes! How could this be ever made!!1 [↩]
- Here's a full discussion of the matter. [↩]
- W / K / m [↩]
- Industrial compressors are really cheap when compared to all this, piping's also not that much of a big deal. [↩]
- 700 / (25 * 250 ) * 100 * 10 / 60. [↩]
- What the fuck do you think "swarowsky" is ? Back when I was a child the house was fucking full of Bohemian glass, my mother still has a closetfull of that crap, vases and fruit bowls three to five kilograms a piece. If I start polishing the pile into half carat "crystals" are you going to buy it from me for twenty billion dollars total ? Idiots. [↩]