Tehran residential tower has been analysed in point of cooling systems, energy usage and energy charges by comparing centrifugal and double effect direct fire absorption chillers and related plant room equipment. Total required cooling load calculated by HAP v4.5 software as 1830 Tons of refrigeration. For calculating energy consumption in cooling system, weather simulation has been done by explaining software. According to the result of energy simulation, energy consumption for double effect direct fire absorption chillers are about 4 times more than centrifugal chillers. Regarding costs of energy, both types are almost in the same condition and it’s due to the government policy in gas and electricity prices.