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SI Psychrometric Chart

version (178 KB) by Muhammad Tauha Ali
This program calculates and plots psychrometric properties of moist air


Updated 07 Apr 2015

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The psyhcrometric properties of air are calculated based on the ASHRAE 2013 handbook of fundamentals (SI version). References to ASHRAE handbook are given in the m-file for easy referencing. Atmospheric pressure of 101.325kPa is considered as default which can be changed by passing the atmospheric pressure value as the last two input parameters i.e. Psychrometericnew ('T',24,'phi',50,'P',101.325)
The Psychrometricsnew.m has the ability to calculate moist air state (Tdb, w, phi, h, v, Tdp, Twb) through input of any of the following functions:
1. Tdb, w 2.Tdb, phi 3.Tdb, h 4.w, phi 5.w, h 6.phi, h 7.Tdb, Twb 8.w, Twb 9.phi, Twb
A psychrometric chart can be plotted using psychplotting.m. The default ambient pressure is taken as 101.325kPa in psychplotting.m. This can be changed by passing the atmospheric pressure value in kPa as the last input parameter.
The program uses label.m for plotting of line labels

Cite As

Muhammad Tauha Ali (2019). SI Psychrometric Chart (, MATLAB Central File Exchange. Retrieved .

Comments and Ratings (17)


Guys, I really need to use this program, but I couldnt get it to work with matlab. Kindly help

I can't understand how to use the program.
Could anyone explain to me?

Kaan Günay

Why is the filename Psychrometricsnew.m while the function is Psychrometrics? Why require the user to change the filename?

Exactly what i was looking for, simple and very helpful. Thank you!

Thanks, really helped me on my project.

Paulo Fonte

There are many psychrometric calculators online, but none gave me exactly what I needed. With this, anyone can easily produce its special chart/graph.

Thanks Muhammad

PS: psychplotting doesn't work with v2012a, but it's me who is outdated ;-)

Can I use this code to plot a diagram with dry bulk temperatures between 0 and 260 Celsius?

Tyler Moore

Ah, optimization toolbox required. Disregard.

Tyler Moore

I'm getting an error for "Unrecognized paramater 'LargeScale'", line 129 of optimset, line 245 Psychrometricsnew, line 8 psychplotting.

Karam Saker

does the calculator work for any two functions?

Chad Greene

The "label" function has just been updated to work with R2014b.


Added functionality of passing atmospheric pressure in the psychrometricnew.m and psychplotting.m files

Updated the psychplotting file to be compatible with MATLAB 2014b

updated file description

MATLAB Release Compatibility
Created with R2014b
Compatible with any release
Platform Compatibility
Windows macOS Linux

Inspired by: label