Example 01: Values from 'tdb' and relative humidity 'r'

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The answers (where available) from the worked example problem are given in the 3rd column in the custom table at the top of the slide image in IP units. It is assumed in this trail that:

In the custom table at the top, where the specific enthalpy conversions from SI units to IP have been deliberately naively performed (as a counter example) using a simple scaling factor - instead of considering the reference offset between SI specific enthalpy and IP specific enthalpy - the values are indicated in the 1st column with an orange warning frame, and depart significantly from the correct answers. This is explained further under:

The Webel Psy library has functions for more accurate conversion from SI specific enthalpy to IP specific enthalpy, however, be aware that there are lots of different variations of British Thermal Units in use!

Below the custom table, the same values generated automatically by a Webel MPsy object (via the CoolProp wrapper for Mathematica) are shown, and then the state position on psychrometric charts in both °F and °C.

An option $opt$psy$doShowAsIP specifies whether the chart should use Imperial Units (°F):

The example uses a Mathematica virtual function Map &/@ over option values {True,False} to output the charts both in °F and °C.

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