Description

Used in Aspen starting with May 2018 release, at which point it replaced the formula from PAM II.

Saturation vapor pressure \(E_{sw}\)(Pa) at temperature \(t\)(K).

Formula

\(ln(E_{sw}) = \sum_{i=0}^{6} g_i t^{i-2} + g_7 ln(t) \\\) where: \(g_0 = -2.8365744\times10^3 \\ g_1 = -6.028076559\times10^3 \\ g_2 = 1.954263612\times10^1 \\ g_3 = -2.737830188\times10^{-2} \\ g_4 = 1.6261698\times10^{-5} \\ g_5 = 7.0229056\times10^{-10} \\ g_6 = -1.8680009\times10^{-13} \\ g_7 = 2.7150305\)

Source

ITS-90 Formulations for Vapor Pressure, Frostpoint Temperature, Dewpoint Temperature, and Enhancement Factors in the Range –100 to +100 C, Bob Hardy, Proceedings of the Third International Symposium on Humidity and Moisture, 1998


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