A cooling system includes a cooling device having a first cooling coil and a second cooling coil, a first heat transfer fluid in fluid communication with the first cooling coil, a second heat transfer fluid in fluid communication with the second cooling coil, a first heat exchanger in fluid communication with the first heat transfer fluid and the second heat transfer fluid, a second heat exchanger in fluid communication with the second heat transfer fluid and a source of external air, a system of fluid control devices in fluid communication with the second heat transfer fluid and configured to minimize a change in a total pressure drop of the second heat transfer fluid when the cooling system switches between operating modes, and a controller configured to selectively control the cooling device and the system of fluid control devices to operate the cooling system in each of the operating modes.