Squirt wrote:
I'm no expert ( at anything at all, but especially not air con ) but using a diesel engine when you have mains supply seems to be making things difficult for no reason. You'd have to mess with exhaust and air vents and diesel storage tanks.
And maintenance.
It must come down to running cost, and as Grim... says, for that to work out it has to be direct drive, and quite an impressively big system.
There is another, quite well proven way to save on aircon costs though, which is to put a big tank of water in the basement, freeze it at night when electricity is cheap, and use the ice to cool air during the day. Seems less likely to catch on fire too