How to estimate the capacity of a chilled water AHU designed for office comfort

[Cofreth]

I have a very old model AHU manufactured by YORK Borg Warner. The name plate of the AHU is missing too.

Is there a general rule of thumb to estimate the cooling capacity by the surface area of the chilled water coil?

Or by blower motor horsepower etc?

Thank you for any input.

[frank]

If it is working you can find the duty from the flow rate and the delta t

[marc5180]

Q = m x Cp x p x DT

[frank]

Can't give you Rep Marc...must spread it around etc lol..

[marc5180]

Thanks anyway Frank

[Cofreth]

If it is working you can find the duty from the flow rate and the delta t

Chilled water flow rate or Air flow? Delta T of air or water? Tq

[frank]

Airflow (volume) over the coil, air on temps, air off temps.

[Magoo]

Delta T DB will give sensible heat capacity, Delta h will give total heat, probably the water test would be easier
Q= water flow rate x DT x 4.2kj/Kg ' C

[moideen]

for example:

Air quantity =370CFM
Temperature of air entering the coil DB = 78F
" WB = 67F
Temperature of air leaving the coil DB = 59F
" WB = 57F
Enthalpy of air at 67F WB = 31.62 BTU/lb
Enthalpy of air at 57F WB = 24.48 BTU/lb
enthalpy deference = 7.14BTU/lb
capacity = 4.5*370*7.14= 11888 BTU/lb