How to calculate the air conditions after the pad and the water evaporation rate.

For this example the following basic data are assumed for a farm:
Air flow q 720 000 m3/h
Pad length L 100 m
Pad length D 0.1 m
Pad type 7090-15
Ambient Conditions:
Dry bulb temperature, t1db1 400c
Wet bulb temperature, t1wb1 190c

1 Calculate the air velocity v
             q
V = -------------m/s
L x H x 3600

720 000
V = ------------- = 1.0 m/s
100 x 2 x 3600

2 Read the pressure drop #p and the saturation efficiency #
Please refer the performance curves

3 Calculate the dry bulb temperature t2db*

t2db = t1db # (t1db-t1wb)
------------------ 0C
     100

t2db = 40- 78 (40-19)
----------- 0C = 23.6 0C
  100

this means that the air is cooled at 16.40c.
(From 400c to 23.60c).

4 Calculate the water evaporation rate E.

Plot the dry bulb temperature t1db = 400c and
t2db = 23.60c on the line( psychometric Chart) for wet bulb
temperature t1wb = 190c.

Read the moisture content before and after the pad, x1=4,9 g/kg and x2=11.8 g/kg.

Then, calculate the water evaporation rate E:

    1.2 x q x (x2-x1)
E = ------------------ It/min
         1000 x 60

   1.2 x 720 000 x (11.8-4.9)
e = --------------------------- It/min
            1000 x 60