Design central Ac system for a mall

I need an energy effecient solution to cool a shopping mall in kenya. The average weather is 30c to 35 outside all year round. The cost of power is high nearly .25 to .30 usd per kwh. The space is approx 30,000 Sg ft per floor. The space needs to be cool through out the day. I need brands and costing approx. the total is floors is 4