Air at a dry bulb temperature of 20C and relative humidity of 80% is to be heated and humidifi ed to 40C and 40% relative humidity. The following options are available for this objective: (a) by...

Air at a dry bulb temperature of 20C and relative humidity of
80% is to be heated and humidifi ed to 40C and 40% relative
humidity. The following options are available for this objective: (a) by passing air through a heated water-spray air washer;
(b) by preheating sensibly, and then passing through a waterspray washer with recirculated water until relative humidity
rises to 95% and then again heating sensibly to the fi nal
required state. Determine for (a) and (b) the total heating
required, the make-up water required in water-spray air washer,
and the humidifying effi ciency of the recirculated spray water.