One question:
how do you estimate that the equipment will probably last 24 months?
It should last a lot more

Regards,
ilpirata79
That was a copy and paste. 2 Years is a good estimate because it will be 24/7 running
You might try submerging the rigs in mineral oil (or some liquid with similar properties) instead of having to use air conditioning to keep them cool. They might last longer this way too. But then again, something could go wrong. .