Psychrometric chart

[SFTB]

Hi,

I'm presently working on a custom application involving a Visual basic program to calculate the enthalpy of humid air to avoid looking in a psychrometric chart. I would like to now the way to calculate the water saturation value for a specific temperature. What is the exact equation? This curve corresponds to the 100% Relative humidity on the chart. Any reference to a book or an internet site would be great. I already use this one

http://www.learninghelper.com/psyc/

What I'm looking for is the equation behind the numbers.

I know that h=cp.t + w.hv
where h is the enthalpy
cp is specific heat of air
t is the temperature
w is the water content
hv is the enthalpy of water vapor at t

thanks,

 

[MintJulep]

ASHRAE Handbook, Fundamentals, chapter 6.

 

[drdust]

Try this web site:

http://www.squ1.com

They have a few neat programs related to HVAC/R and Building dynamics.

 

[billspen]

check this web site out

http://www.hvacware.net/engrproj.html

The equations you need are written in Vbasic here for Excel.