Evaporative cooler wet and dry mode control

A method of controlling a hybrid evaporative cooler system, the method comprising:

• cooling a process fluid from a source using a cooling coil located in an airstream downstream of an evaporative cooler, the evaporative cooler operable together with the cooling coil in a wet mode;
• and
• receiving a leaving process fluid temperature set point;
• determining a minimum supply fluid temperature deliverable by the cooling coil in a dry mode where the evaporative cooler is deactivated based on a coil performance model;
• and
• operating the hybrid evaporative cooler system in the dry mode when the leaving process fluid temperature set point is greater than the minimum supply fluid temperature.

A hybrid evaporative cooler system comprising:

• an evaporative cooler located in an airstream;
• a cooling coil located in the airstream downstream of the evaporative cooler and configured to receive a process fluid from a source;
• and
• a controller configured to enable and disable the evaporative cooler and the cooling coil, the controller further configured to:
• receive a leaving process fluid temperature set point;
• determine a minimum supply fluid temperature deliverable by the cooling coil on condition that the evaporative cooler is off based on a coil performance model;
• and
• disable the evaporative cooler on condition that the leaving process fluid temperature set point is greater than the minimum supply fluid temperature.