3 replies to this topic

[jmendiguren]

I need to perform accurate calculation for wet bulb temperature based on dry bulb temperature (ºC or ºF) and relative humidity (%). I use calculations based on empirical data as published in the ASHRAE document called "Computarized Algorithims for Psychrometric Aproximations".
1) Is this a accurate method?
2) Which is the best procedure to calculate accurate wet bulb temperature?

[ankur2061]

jmendiguren,

Whether the ASHRAE method is accurate or not I cannot comment, however, I do believe that ASHRAE has researched & published extensive literature related to psychrometry and I personally would go with the methods and procedures suggested by them.

I have posted an excel sheet which you can utilize to calculate WBT in an indirect way. The inputs in this sheet "State Point" require "DBT", "WBT" and altitude to be provided which in turn will provide the outputs as "Atmospheric Pressure", "Vapor Pressure at Saturation", "Vapor Pressure", "Dew Point Temperature", "Relative Humidity", "Humidity Ratio", "Enthalpy" and "Specific Volume". You can adjust the relative humidity to your desired value by using the "goal seek" function in excel to arrive at the WBT given the DBT and altitude.

The link is as follows:

http://www.cheresour...6833#entry26833

Regards,
Ankur.

[breizh]

An other resource :

http://www.uigi.com/WebPsycH.html

Hope this helps

Breizh

[jmendiguren]

jmendiguren,

Whether the ASHRAE method is accurate or not I cannot comment, however, I do believe that ASHRAE has researched & published extensive literature related to psychrometry and I personally would go with the methods and procedures suggested by them.

I have posted an excel sheet which you can utilize to calculate WBT in an indirect way. The inputs in this sheet "State Point" require "DBT", "WBT" and altitude to be provided which in turn will provide the outputs as "Atmospheric Pressure", "Vapor Pressure at Saturation", "Vapor Pressure", "Dew Point Temperature", "Relative Humidity", "Humidity Ratio", "Enthalpy" and "Specific Volume". You can adjust the relative humidity to your desired value by using the "goal seek" function in excel to arrive at the WBT given the DBT and altitude.

The link is as follows:

http://www.cheresour...6833#entry26833

Regards,
Ankur.

Thanks, this file is just what I have used for ASHRAE calculation
Regards
Jose Mendiguren