A 12,000 BTU window A/C unit is actually *2 tons* not 1 ton.
I have to correct you on this.. 12,000BTU/hr is equal to 1 Ton of Refrigeration or 1TR is also equal to 3.51kW of heat
Never mind, you're right - I think I was thinking of the heat of evaporation for water.
I've done the "use an A/C but don't recirculate it" partial cooling option for a while - it's a tradeoff, doesn't cool as well but doesn't COST as much either, and you can always set it so the A/C only kicks on when the temp is gonna be TOO hot for the miners....
Even if it only brings the intake air down 5 degrees it can be a big help.