Wrapping things up

So, does this cover every detail? Of course not.

For one thing, we didn’t integrate the bypass factor, which accounts for the fact that not every air particle running through the cooling coil is affected by the decrease in temperature.

And what about all the different methods of energy recovery, like the heat recovery wheel, twin coils or cross heat exchangers? Or adiabatic humidifying?

Like I mentioned above, this is a quick and dirty description of how the Mollier diagram can be used to give a fairly accurate estimation of an air handling unit’s capacities.

To get familiar with the diagram, you can try using different conditions. This example only included summer conditions: see what happens with the capacity of the heater and steam humidifier when you set the outside conditions to -5 °C and 20% RH.

People who followed him would be free of this tedious job forever. In that sense, you can see Mollier as one of the first programmers, making complex tasks easier and more efficient. And we are still using the solution he found more than a hundred years ago!