How is a psychrometric chart for other than sea level atmospheric pressure generated?

  • #1
Sorry, no thermo reference handy to try and figure it out myself. It would be nice to know, in case our company does any work up on the mountain (on a new telescope project coming up).
 

Answers and Replies

  • #2


Well, the psychrometric chart is generated from experimental data, but I'm sure you could determine gas-vapor properties for air at a different pressure using the fundamentals and your thermodynamics text. However I believe ASHRAE publishes charts for a variety of elevations and you can order one through them. My HVAC design prof mentioned having to get one for his work in our state of Colorado. Hope that helps some.
 
  • #3
Mech_Engineer
Science Advisor
Gold Member
2,575
172


Sorry, no thermo reference handy to try and figure it out myself. It would be nice to know, in case our company does any work up on the mountain (on a new telescope project coming up).

Air density and water vapor pressure play a primary role in the layout of the psychrometric chart, so when going up in altitude they must be accounted for. There are manual calculations available that enable you to calculate the values, or you can just look up a psychrometric chart at or near the altitude you're looking for.

For example, my work is at 7000ft above sea level. As such, I have used a psychrometric chart for that altitude in the past. Similar to this one: http://www.luhow.com/client/coolerado.com/CoolTools/Psychrmtrcs/7500PsychrmtrcLetter.pdf" [Broken]

There are also several calculation software packages available that have psychrometric calulcation abilities, and I assume they can compensate for altitude changes.
 
Last edited by a moderator:

Related Threads on How is a psychrometric chart for other than sea level atmospheric pressure generated?

Replies
4
Views
728
  • Last Post
Replies
5
Views
997
  • Last Post
Replies
3
Views
2K
  • Last Post
Replies
16
Views
8K
Replies
9
Views
11K
Replies
6
Views
2K
  • Last Post
Replies
0
Views
4K
  • Last Post
Replies
6
Views
9K
Replies
3
Views
805
Replies
5
Views
1K
Top