Which of the following is NOT classified as a thermodynamic property of refrigerants?

The correct classification of thermodynamic properties is essential for understanding how refrigerants behave in various conditions, particularly in refrigeration and air conditioning systems. Among the properties listed, the critical point, as chosen, is typically regarded as a defining characteristic of a refrigerant's behavior at the boundary of its liquid and vapor phases.

However, all the listed properties are indeed critical in evaluating refrigerant performance and efficiency, except for the critical point when considering practical applications such as boiling and freezing points, which directly influence the refrigerant's phase at operational temperatures. The boiling point indicates when the refrigerant transitions from liquid to vapor, while the freezing point denotes the temperature at which it solidifies. Specific heat is a measure of the heat energy required to change a given mass of a substance by one degree of temperature and is crucial for thermodynamic calculations in HVAC applications.

In this context, the critical point is seen as a relative measure rather than a direct thermodynamic law governing the state of refrigerants during typical cycles in heating and cooling systems. Therefore, understanding these distinctions is pivotal for HVAC professionals when selecting and working with refrigerants in practical scenarios.