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Message No. 13893, Started by devitg on 05/11/04
Talking about psichrometry
Given T in Kelvin or absolute temp
For Pws [presure water steam]
Is this formula valid ?
for Water air from 0 to 200 C degree
ln Pws= a/t + b+c*t+d*t^2+e*t^3+f*lnT

for the followings values

a      -5800.2206
b      -5.5162256
c      -0.048640239
d      4.18E-05
e      -1.45E-08
f       6.5459673

I used it for 100 C dgree and give
p mbar      1014.217979 mbar , that is a normal atmospheric pressure

My concern is if it is valid for the air ambient temperature

I wan to calc the Relative humidity by reading the DryBulb and WETbulb  temperature.

I have 2 data loggers and  I modify one of them to read wet bulb temperature, so I can charge the data from it to a spread sheet and get the HR %  .

maybe it is not a conventional way of doing , but is it what I have and will have  for ever. (lack of money to buy a HR datalogger)

Hope you can give me any advice.

PS I have the spread sheet done.

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Follow-up Messages (1)
If I understand you correctly, you want to confirm the validity of your equ...
No. 13895, Posted by mbeychok on 05/11/04, 10:29 PST.
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