@Jamphone I am interested if you could elaborate your response regarding it not paying for itself.
So air conditioning - absent a circulation system that has access to cold air - will use as much energy to cool the air as the SP35 used to heat the air, which is basically all of the energy that went into the SP35. Computers radiate out more than 99% of the energy that goes into them as heat.
If you have an ability to pump in cold air, you may be able to reduce your air conditioning costs.
But if this is straight AC, then you will essentially double your energy usage. Right now, this SP35 will us roughly 2500 KW a month, and cost up to 2500 KW a month in AC. So that's a total energy usage of 5000 KW. 5.5 TH will make you $400/month right now.
So if your power is 10 cents/kwh, you'll be losing $100/month at a full 100% AC set up.
So presuming a slightly more efficient AC set up, you'll be breaking even. ie. The increase in your power bill will be as much as you mine each month.
That'd be a pretty crappy AC. Datacenters sometimes use a 1:1 rule because AC can be implemented crappily in old DC, but that is not the fault of AC itself.
The COP of a decent air conditioner with a
SEER of 16 is 3.75, which means you need to use 1J worth of AC to remove 3.75J of heat. In power terms, it would take 1W of A/C to remove the heat from 3.75W of power, and would vent 4.75W outside.
Even cheap old ones should have a COP of 3 or so. The minimum the US has allowed to be sold for residential use since 2006 (at least according to that WP article) is SEER 13 or COP 3.2.
