Explain the Working of Air Washer with the Help of a Suitable Diagram.

Air washer is a device that may be used for:

(a) Cooling and dehumidification

(b) Cooling and humidification

(d) Humidification

(e) Adiabatic saturation

(f) Cooling.

The schematic diagram for air washer is shown in Fig. 37.7.

Following are the processes that can be carried out with the help of washer shown in Fig. 37.7 and they are shown on psychometric chart of Fig. 37.8.

They are:

i. 1-2a Sensible Cooling:

Water temperature is equal to dew-point temperature of air.

ii. 1-2b Adiabatic Saturation:

It takes place along the wet bulb temperature line. Water is at WBT

iii. 1-2c Cooling and Dehumidification:

Temperature of water is below the dew point temperature of air.

iv. 1-2d Cooling and Humidification:

When wet bulb temperature is less than water spray temperature and this spray water temperature is less than the dry bulb temperature of air, this cooling and humidification process takes place. The water is required to be heated externally.

v. 1-2e Humidification:

Water spray temperature is equal to the dry bulb temperature of air. The water externally heated. (Latent heat of evaporation)

vi. 1-2f Heating and Humidification:

If the spray water is heated and maintained at temperature higher than the dry bulb temperature of air entering the washer. In this case, the dry bulb temperature of air leaving the washer is more than the inlet temperature of air. Wet bulb is higher than the initial WBT and higher humidity ratio than the entering air.