Effects of different water-cooled heat sinks on the cooling system performance in a data center

•Cooling water operation parameters under different heat sink were optimized.•Fitting correlation on affordable extreme atmospheric temperature is given.•The B-type system can achieve significant energy savings compared to the A-type system.•The B-type can meet the year-round cooling demand via a cooling tower cold source.•Optimal water flow rate fluctuation clearly responds to different atmospheric conditions.