The use of air conditioning equipment is becoming more frequent, and new technologies are emerging to increase the efficiency of the process and decrease the operating costs of air conditioning systems. In data centres, where electric power consumption is high and indoor cooling is a constant, the air conditioning systems are responsible for a large part of the building's energy consumption. In this work, a data centre with a twenty years old cooling system (with production of chilled water), was analysed and is about to be replaced. In order to meet the thermal load of the building, two solutions were proposed with a more efficient refrigeration system: one with production of chilled water (case 1) and another one with a direct expansion system (DX, case 2). It was also analysed the possibility to use free cooling in both of them. In both cases the results obtained shows a significant reduction on the energy consumption and consequently a reduction in the CO2 emissions, regarding the old system. An economic analysis was also carried and the conclusions were that they are profitable. The final decision is due to the customer.
