Giovanni S. Crisi and Gisela H. Gomes, professors at at Mackenzie Presbyterian University, Sao Paulo, Brazil, along with their undergraduate student, Priscila Hirota, developed the easy-to-use dew point graph above. Gomes mathematically deducted a companion equation, allowing users to calculate dew point with no need to use the graph:
Where: DPC is dew point at compression pressure DPA is dew point at atmospheric pressure, and a and δ are factors based on the compression pressure from the table below.
The graph has been based on the thermodynamic properties of moist air. Nevertheless, they deducted that the straight lines follow the general equation.
For more information, contact Prof. Crisi at gscrisi@mackenzie.com.br.
Pressure, |
a |
δ |
0 |
100 |
0 |
15 |
96.1 |
-5.6 |
30 |
93.9 |
-17.8 |
60 |
85.5 |
-30.1 |
100 |
81.5 |
-36.9 |
150 |
77.9 |
-44.1 |
200 |
75.4 |
-48.1 |
300 |
74.1 |
-58.0 |
600 |
68.6 |
-66.1 |
900 |
66.9 |
-69.3 |
1200 |
63.3 |
-72.7 |
