A substantial reduction of air flow rate can be achieved in process areas with large sensible heat gains, by the addition of water sprayed into the room.

Close control of room temperature and relative humidity to meet process conditions is also accomplished by the use of water spray and VAV. A deionized water spray system with VAV, installed in a large finishing area of a southern paper mill, resulted in a reduction of one 40 thousand cfm (18.8 kl_/s) air handling unit and associated air distribution system.

The use of a DDC controlled VAV system for humidity control reduced energy consumption considerably. This is illustrated by psychometric analysis at part load conditions.

The DDC control sequence describes the operation for both humidity and temperature control.