Question

what is meant by mollier diagram? Explain.

Answer 1

Mollier Diagrams

The Mollier diagram is a graphic representation of the relationship between air temperature, moisture content and enthalpy - and is a basic design tool for building engineers and designers. Compressor performance cannot be accurately predicted without detailed knowledge of the behavior of the gas or gases involved.

Mollier Diagrams are readily available for most pure gases at “conventional” pressures and temperatures. However, in cryogenic areas or at very high pressure, some gas behaviors are difficult to predict. Gas properties in these areas therefore have been estimates determined through rather empirical methods.

The behavior of a wide variety of gases—in any conceivable mixture—can be accurately computed, plotted, and offered to the process engineer in the form of a Mollier diagram .

The only input required to obtain a plot of gas behavior is the identity and proportion of the gases involved (if a gas mix), and the limiting pressure and temperature values.

Temperature entropy (T-S) and pressure enthalpy (P-h) curves are commonly used to display gas properties. While these curves are primarily used for steam or refrigeration cycles, the curves are very useful for any process. The process is easy to “visualize” when plotted on a Mollier diagram. One can “see” the phase change, the expansion, or the compression process, and therefore easily comprehend the overall process and the effect of process changes.