What is a graphical representation of air properties called?

The correct answer is a psychrometric chart. A psychrometric chart is a graphical representation that illustrates the physical and thermal properties of moist air. It depicts various parameters such as temperature, humidity, enthalpy, and energy, which are crucial for understanding and managing air conditions in HVAC applications.

By using a psychrometric chart, professionals can visualize the relationships between different air properties, making it easier to analyze air conditioning processes, determine comfort levels, and conduct energy assessments. This chart includes lines of constant dry bulb temperature, wet bulb temperature, relative humidity, and more, enabling users to see how changes in one property affect others.

Other options do not serve this specific purpose. A ventilation map is generally used for illustrating air circulation patterns, a thermodynamic diagram typically pertains to the behavior of gases and fluids under various conditions, and an airflow graph may depict the flow rates of air but lacks the comprehensive view of the air's thermal and moisture properties.