Hi,
I'm a bit dubious that an air conditioning system is going to do the trick.
It would take many hours for a warm peice of tooling grade aluminum to cool to ambient temperature even if the ambient is controlled.
The real issue is that you are adding heat to the material much faster than could be removed by a temperature controlled air environment.
If your spindle is consuminng 2kW then its possible that about 500W of heat is going into the work material, you'll never remove that much with
air (gas) cooling.
The solution is to use flood cooling, and lots and LOTS and LOTS of it, well in excess of 20litre/min.
Craig