Can you help me with the math? How much energy will the system draw per hour? 3.5kw per what(hour? minute?)?
The unit of measurement you are looking for is called kWh or Kilowatt-hour, any thing that runs on electricity will have a label stating the draw in watts or kilowatts, it will be "W" or "KW".
To convert from W to KW you simply divide the number 1000, and then convert it to kWh you just multiply the KW by the number of hours you want to measure.
Example 1:
For a miner that uses 1200w, we divide it by 1000 to get 1.2k, to check how much it "consumes" in 3 hours, just do 1.2kw*3h = 3.6kWh.
Example 2:
A miner that uses 800w, divide by 1000 you get 0.8KW, to see how much it "consumes" in 30 mins you x it by 0.5 and you get 0.4kWh.
The average 10 or 15 solar arrays on the house roof can't handle mining operations, you will hardly be able to run your own miner on it, let alone "HOST" other people's miners.