To cool racks of electronic devices, the racks are arranged in a plurality of rows to define at least a first aisle and a second aisle, where the second aisle has air cooler than air in the first aisle, and where the fans of the electronic devices cause air to flow from the second aisle to the first aisle. A cooling coil assembly contains a coolant to cool air received from the first aisle, wherein cooled air exits the cooling coil assembly and flows to the second aisle. A temperature of the coolant in the cooling coil assembly is maintained above a dew point of an environment in which the racks are located.