Is there any way to calculate the specific humidity of air based on just the dry bulb and wet bulb temps?

Question

If not what other variables would i need? I am trying to have it so an excel file will calculate it without me having to input the specific humidity based off looking at the psych chart.

Answer 1

There is no direct relationship with wet bulb to anything. It is determined experimentally and is utilized mostly to find the state point on the psych chart. You might do what you want with dry bulb and with dew point. There is a variable relationship between dp and absolute (specific) humidity (lb of moisture/ lb of dry air) which relationship is tabulated. This will relate to latent heat just as the db will relate to sensible heat.

Answer 2

If you have a Psych chart, you could pick it off immed. This is a plot of dry bulb, wet bulb, humidity, RH, and incl the saturation line. HVAC engrs find this invaluable.