Simple model for the oscillations at the output of an evaporator.

The oscillations of temperature at the output of an evaporator are a well known phenomenon, to be put into correlation with the instability of the control loop of the thermostatic valve. A simple model is proposed in order to explain physically the connection between the oscillations and the so-called minimum stable signal. A good correlation can be achieved looking at the shapes of the experimental and calculated curves. The model let to conclude that the minimum stable signal line could be defined in a more precise way.