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How is a Mollier diagram used?

To illustrate how the diagram is used, the following diagrams show typical processes used in HVAC systems.

Heating and cooling

If increasing sensible heating only, there is no increase of moisture.

If cooling without condensation, there is no change in moisture content. This is called sensible cooling.

If cooling with condensation, the moisture content will reduce. This is called sensible and latent cooling.


If humidifying by evaporation of cold water, there will be adiabatic humidification with no change in enthalpy.

If humidifying with steam, there could be isothermal humidification which means no change in temperature. But the air can be heated depending on the temperature of steam.