In an air conditioning plant, airflow rate of 2 kg/s passes through a spray water humidifier with a contact factor 0.7. Determine the moisture content and temperature of the air leaving the humidifier and the amount of make-up water needed. The dry and wet-bulb temperatures of the inlet air are 25 C and 15 C respectively.
| Inputs |
Units |
|
|
Inlet air, DBT |
24,00 |
C |
|
Inlet air, WBT |
15,00 |
C |
|
Inlet air, mass flow rate |
2,00 |
kg/s |
|
Contact factor of the humidifier |
0,70 |
. |
|
Atmospheric pressure |
1,01 |
bar |
The contact factor of a humidifier is defined as the efficiency for humidification. A 100% efficient humidifier will bring the moisture content of the air to the saturation moisture content at the apparatus dew-point, mcC. The contact factor of the humidifier can be defined by the moisture content differences:
cf = (mcB - mcA)/(mcC - mcA)
or
cf = (hB - hA)/(hC - hA)
| Output | ||
|
moisture content of inlet air |
0,0068 |
. |
|
moisture content at ADP |
0,0106 |
. |
|
moisture content of outlet air |
0,0095 |
. |
|
make-up water req. |
0,0054 |
kg/s |
|
Spec. enthalpy at inlet |
41,4 |
kJ/kg |
|
Spec. enthalpy at ADP |
42,0 |
kJ/kg |
|
Spec. enthalpy at outlet |
41,8 |
kJ/kg |
|
Dry-bulb temp at outlet |
17,70 |
C |