SoD
Mechanical
- Nov 21, 2018
- 8
In calculating cooling load of outside air,
Data:
Data:
Inside -
Equation:
SH Load = mass rate * Cp * dT
LH load = mass rate * Cp * dW
Method 1: (It is mostly used in HAVC applications)
Considering standard air properties,
cp = specific heat of air = 1.006 kJ/kg oC
ρ = density of air = 1.202 kg/m3
OR
Method 2:
Considering separate conditions and values such as,
Outside condition Inside condition
Temp (deg cel) 40 25
Humidity ratio (in Kg/ Kg of air) 0.026247157 0.010983205
Cp (Kj/Kg K) 1.007 1.006
density (Kg/m3) 1.127 1.184
Both methods give huge difference in answer.
Please help in choosing correct way.
DBT (in ℃) = 25
Wi (in Kg/ Kg of air) = 0.010983205
Wi (in Kg/ Kg of air) = 0.010983205
Outside
DBT (in ℃) = 40
Wo (in Kg/ Kg of air) = 0.026247157
DBT (in ℃) = 40
Wo (in Kg/ Kg of air) = 0.026247157
Air flow rate = 3 m3/sEquation:
SH Load = mass rate * Cp * dT
LH load = mass rate * Cp * dW
Method 1: (It is mostly used in HAVC applications)
Considering standard air properties,
cp = specific heat of air = 1.006 kJ/kg oC
ρ = density of air = 1.202 kg/m3
OR
Method 2:
Considering separate conditions and values such as,
Outside condition Inside condition
Temp (deg cel) 40 25
Humidity ratio (in Kg/ Kg of air) 0.026247157 0.010983205
Cp (Kj/Kg K) 1.007 1.006
density (Kg/m3) 1.127 1.184
Both methods give huge difference in answer.
Please help in choosing correct way.