Dry Mode
- The unit maintains dry mode operation until the temperature set point can no longer be met
- While in dry mode, no water is used, thus plume is eliminated
- Dry mode operation can save thousands in water usage and sewage costs annually

In dry mode, the process fluid enters the Ellipti-fin® coil through the top coil connections. The fan motor is energized, while the spray pump is turned off. The axial fan draws air upward through the louvers and across the coils. As the air passes over the coil, a portion of the load is dissipated to the atmosphere through the tube walls and fins using sensible heat transfer. The cooled fluid then returns to the process via the bottom coil connection. The unit will remain in the dry mode of operation until the temperature set point can no longer be met. In this mode, NO water is used and plume is eliminated.
Wet-Dry Mode
- Unique to the eco-ATWB-E
- Once the temperature set point can no longer be met, the unit switches to partial evaporative mode
- This mode of operation greatly reduces water usage while still maintaining the temperature set point

The joint wet and dry operation mode provides water savings as well as low approach temperatures. In this joint mode of operation, the fan is on and the process fluid enters the coils through the top coil connections (Fan on, Pump A on, Pump B off). Recirculating pump B is turned off and coil B rejects a portion of the heat load to the atmosphere through the tube and fin walls to the air passing over the coils through sensible heat transfer. Pump A is on, and heat from the process fluid transfers through the coil tubes to the water cascading downward over coil A. This mode of operation minimizes the amount of water used while maintaining the cooling capacity required. The cooled fluid then returns to the process via the bottom coil connection.
Evaporative Mode

Once the temperature set point can no longer be met, both recirculating pumps are turned on and the unit runs in full evaporative mode. As the axial fan draws air upwards over the coils, water cascades downwards, and heat from the process fluid transfers through the coil tubes to the water. The cooled fluid then returns to the process via the bottom coil connection.