Idris,
The design outlet fluid temperature is the outlet fluid temperature
that you would get if all the inlet conditions were at the design
condition. The design outlet fluid temperature is not a "set point"
temperature that the tower is trying to achieve. If you are trying to
achieve a certain outlet temperature then you have to set that
temperature as the 8th input and you have to set the fan control signal
(input 7) to -1 (as it says in the "more" buttons for the Type). If you
are not trying to control the outlet liquid temperature but just want it
to be closer to the wetbulb temperature then you have to increase the
air flow rate that the fans are providing.
regards,
David