A key reason for having a buffer is to ensure enough thermal inertia so that the compressor does not stop a few minutes after starting.
Minimum run time
The compressor needs sufficient continuous running time for better efficiency and less wear.
The role of water volume
A larger active volume slows down temperature changes and increases running time.
Proper sizing
The required volume depends on the minimum power of the machine, the allowable ΔT, and the desired running time.
