In an air conditioning plant, airflow rate of 2 kg/s passes through a steam humidifier. Determine the load on the humidifier and the steam supplied. The dry and wet-bulb temperatures of the inlet air are 9 C and 3 C respectively. Air leaves the humidifier with moisture content of 0.008
| Inputs |
Units |
|
|
Inlet air, DBT |
9,00 |
C |
|
Inlet air, WBT |
3,00 |
C |
|
Inlet air, mass flow rate |
2,00 |
kg/s |
|
Outlet air, moisture content |
0,008 |
. |
|
Atmospheric pressure |
1,01 |
bar |
Steam can be directly injected to air stream for air conditioning purposes. In this process, all the latent heat necessary for evaporation of water is added outside the air stream. The supply of water vapor increases the enthalpy of the air. The temperature increase in this process is negligible and it can be assumed as an isothermal process with good approximation. Load on humidifier is:
Q = mA * (hB - hA)
and the steam supplied by humidifier is:
mSteam = mA * (mcB - mcA)
| Output | ||
|
moisture content of inlet air |
0,0022 |
. |
|
Outlet air, DBT |
9,0000 |
. |
|
Spec. enthalpy at inlet |
14,5 |
kJ/kg |
|
Spec. enthalpy at outlet |
29,2 |
kJ/kg |
|
Load on the humidifier |
29,4102 |
kW |
|
steam supplied |
0,0117 |
kg/s |