Wet Bulb Calculation from Dry Bulband Dew Point 1

[awtrask]

I am looking to use real weather data from the last 30 years in some calculations and I can only find data available that has dry bulb temperature, Dew Point, and pressure data. Does anyone know of a function I can use in Excel, I realize it will have to involve VB, that can do these calcs for me? I am working with hourly data over 30 years, so I do not have any desire to do this by hand.

Alternatively is the an equation I can use to approximate the Skew-T diagram? I think I can calc it from there, but I am not positive.

Thank you

 

[MintJulep]

Many psychrometric calculation add-ins for Excel.

This one

http://www.megawatsoft.com/excel-add-in-libraries/psychrometric-properties-excel.aspx

for example.

 

[awtrask]

Thank you.

Do you think that is the best add-in? It seems as thought the demo works well and I verified a few answers via multiple online calculator's, but if you mentioned there are several do you have a recommendation?

 

[IDS]

Previous thread that looks like it might be useful:

http://www.eng-tips.com/viewthread.cfm?qid=144858

Doug Jenkins
Interactive Design Services

http://newtonexcelbach.wordpress.com/

 

[MintJulep]

That was just the first one I looked at from many Google hits.

There are plenty of free ones too.

 

[ImaKnight]

Thank you.

 

[trashcanman]

Use the formulas in ASHRAE Handbook of fundamentsls in Psychrometrics. That is sure-fire.