So my latest procrastination had several design requirements:
- Must ventilate most of its heat to the outside (hot Australian summer at the moment)
- Must not be audible from any part of the apartment (as declared by the minister of Finance and Tribal Warfare.) outside of the spare bedroom
- Must not burn down the place if some shitty PSU cable/connector catches on fire
But first, some history... The existing solution that worked for ~half a year for my CPU miners (Primecoin/Protoshares): I had installed most of the stuff under the home entertainment unit, complete with fan intake and ventilation duct (this was when I was single, can you tell?
At its height, there were 7 computers in there, ~500 watts of heat nicely ventilated outside. Ambient temps are often 30 deg C all day where I live so more heat from mining is not required...
Anyway, certain people found this setup in the living room unacceptable and a new solution that met the criteria above was created...Mining box!http://i.imgur.com/5LwchAJ.jpg
Home of the mining boxhttp://i.imgur.com/YN8jNaV.jpg
Since the first pics, some motherboards had died, other systems were repurposed. As a result, the mining box would house:
1x core 2 quad q6600, dual radeon 7790s
1x core 2 duo E8400, 1x radeon 5750
2x core 2 duo E7500, (CPU only)
16 port gigabit switch
Here is the power infrastructure, networking (including switch) hidden under a plane of glass. On the right are the two E7500's and in the middle is the E8400 and shitty old 5750 card:http://i.imgur.com/EI7qYt6.jpg
The Q6600 and 2x 7790 placed on top of the glass which sits sort of diagonally:http://i.imgur.com/5YP4hDO.jpg
As it turned out, it was very hard to cool this thing while keeping it more or less silent. Most of the things in the box were quiet, but most of the AC powered fans I had to ventilate it were too noisy. I finally tore this rotary vane (squirrel cage) fan out of an old portable air conditioner. I added a cord and switches for it. It has three motor winding taps and can run at 85, 155, or 185 watts (@230 volts). Unfortunately all of these were simply too loud. Even at the lowest fan speed it creates reverberations that can be heard from the other side of the apartment. The solution is to run it on the lowest setting, through a step down transformer that outputs @ 130 volts. This limits the total power consumption (and noise) to 28 watts. The clips on the side are to hold on the dust filter. The plastic lid placed on top of the CPU heatsink is to deflect some of the air coming down from the fan, which can make an annoying whistling noise:http://i.imgur.com/pLjv8CD.jpg
The box is pressurized by the big fan, and hot air flows up through a duct to the window above:http://i.imgur.com/nB1WvUj.jpg
Making the wooden window frame and getting the duct to stay in it was a huge pain in the ass. I finally settled on a ventilation fascia installed into the wood, which gave a point to secure the duct to. Its held in place with some reusable zipties and screws.http://i.imgur.com/7GEIj6J.jpg
Unfortunately, as I discovered later on, making the fan silent by running it at lower RPMs reduced the flow rate too much and things were getting too hot. As a result the Auxiliary Air Accelerator(TM) was created for $9. I'll eventually cut out some metal at work that will make this duct connection and entire top of the box much neater.http://i.imgur.com/RJedYNF.jpghttp://i.imgur.com/B32i1SX.jpg
The final setup as it probably will be left from now on:
*I changed the step-down transformer to a 1000 VA model so all of the motor speeds can be used if neededhttp://i.imgur.com/WNOe5xJ.jpg
There is another two 7790's and a watercooled 6870 (display device) on the HTPC, now much lonelier without its CPU mining brethren:http://i.imgur.com/55WOwDc.jpghttp://i.imgur.com/y9UZa2E.jpg
So numbers? The CPU mining across all of my systems makes about $8 revenue per day. Mining dogecoin across all my GPU makes about $20-22 revenue per day most day. Power cost per day @0.30 AUD/kWh is about $8 to $9. I have some outdated ASIC strapped to the cooling fans of my makeshift NAS pile which get about $0.15/day? (
The end... for now...