The pressure-enthalpy (P-H) diagram is a useful tool for refrigeration engineers and designers. It is also useful for service technicians.
The P-H diagram is a graphical representation of the refrigerant as it travels through the refrigeration system. It can be used to predict several system conditions, such as the pressure and temperature for the refrigerant at various locations within the system. It can also be used to demonstrate the effects of system changes to these conditions.