I saw answers to your mails, and it seems to me that your problem is about
the cool air distribution.
what type of diffusers are you using ?
If you have the right amount of cool air (right air flow for the volume and
right temperature) you should be able to cool your rooms.
If you have high ceilings the best is to use displacement ventilation
(installed on the floor)
If you are supplying cool air from high ceilings you will have a mixing with
the hot air close to the ceiling and at the end warm air close to the
But if your installation is already built you can't change the system.