Pan steam humidifier, Using Thermo Utilities, MS Excel Add-ins

In an air conditioning plant, airflow rate of 2 kg/s passes through a pan 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


 

A pan steam humidifier uses a heating element inside a water tank. The tank is mounted at the bottom of the air duct. The air flowing over the water surface will cause some evaporative cooling which results in drop of air dry-bulb temperature. The ratio of sensible heat to total heat is approximately 0.2

Load on the 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

12,66

C

Assumed

Spec. enthalpy at inlet

14,5

kJ/kg

Spec. enthalpy at outlet

32,9

kJ/kg

Load on the humidifier = total heat

36,8061

kW

Sensible heat

7,3591

kJ/kg

Qs / Q = 0.2

0,1999

.

Goal

Use the solver to reach the goal

.

.

steam supplied

0,0117

kg/s


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