Why don't you go with option 1 which is where you have the experience? There are after market solutions for the S9, I'm sure the same (Chinese) sources will put out aftermarket water cooling kits for the S15.
I just would love to water cool it. As I know I would be able to render it silent, I already have enough rads to do that. But I have been unable to locate a source for water block. And the only block I was able to find for an S9 is aluminum. That would be a complete waste of money. I would only use copper blocks. Never put aluminum in a water loop.
I would invest the time and money into designing and producing a water block for the S15 if I knew there would be others interested in buying some blocks to offset the cost. But the useful life of a miner is 2 years at most. Not sure there would be a market there. I'm pretty sure I would have to pay at least 1000$ for a prototype to be made.
I can see computer guys water cooling because it's more of a hobby to them. But miners have profit in mind more than the hobby or cool factor. Not too many miners would justify paying upwards of 4-500$ for a water cooling system.
Did you take into account the maintenance hassle that involves mineral oil?
I only briefly looked into mineral oil. It would be interesting if I could use my water rads/pumps/stuff for it. But I think oil would be too viscous for water rads and water pumps.
There is another dielectric liquid used for refrigeration, cleaner like water but expensive...
Please tell me more.
Option 3 sounds interesting as well, maybe with some 3d printed adapter?
I have access to an English wheel and a metal shop. So the shroud or adapter wouldn't be too hard to figure out.
The stock fans I believe are rated at around 38 cfm at max speed. But those ratings are usually in open air without restrictions. Once you add some restrictions like the inside of a miner, or a rad, or a dust filter, that rating goes way down. The squirrel fan I have and would use as replacement has a rating of 630 cfm at full speed and much higher pressure too. So it wouldn't be affected by restrictions as much.
I'm thinking the added cooling of such a fan would allow me to OC a bit. But I would be happy if all I can do is run stock clock quietly.
But I am curious as to how much of the fan noise on the stock S15 is from the actual fan, and how much is from the air rushing around in and out of the miner. Pushing air through a bunch of heat sinks inside a miner is going to make some noise. I'm just not sure how much.
Any cheap case/cpu fan would happily report rpms, you can even remove the blades, and you don't need the fourth control wire either.
Exactly my thoughts. It wouldn't be too hard to fake a fan rpm signal. And even easier to just trim off the fan blades and allow the fan purely as rpm reporter.
So this is a good idea if you want to feel like you are a part of the bitcoin network, but just know all the added costs of quieting the miner means your chances of ever even breaking even are pretty poor
In my specific case, water cooling wouldn't be expensive at all as I already have everything, spare the water block. That one would be pricey. And I don't think I could offset the cost with selling a few blocks to other guys. It wouldn't be much of a market from where I stand.
The 3rd option would also be pretty cheap for me if it works. I already have the fan. I just would need a few hours of labor to make the shroud/adapter.
Also I am in an apartment complex with free power as part of the rent. So if I only have one or two miners, nobody else will notice the small hike in power usage. I share the power meter with an other 24 units.
