What is the primary function of a D-X Coil in refrigeration systems?

The primary function of a direct expansion (D-X) coil in refrigeration systems is to cool air. In these systems, the refrigerant inside the coil evaporates as it absorbs heat from the air that flows over the coil. This process cools the air, which is then circulated throughout the space that needs to be cooled. As the refrigerant evaporates, it effectively transfers heat away from the air, providing the necessary cooling effect.

The definition and operation of a D-X coil are essential in understanding HVAC systems, as they play a pivotal role in maintaining comfortable temperatures in various environments, whether in homes, offices, or industrial applications. The cooling process is efficient because it directly cools the air entering the space, keeping energy consumption relatively low compared to other methods of cooling.

The options that suggest cooling liquid or heating air do not align with the function of a D-X coil, as coolant and heating require different components and mechanisms. Additionally, while moisture removal is a benefit of the cooling process (condensation occurs when humid air contacts the cooled coil), it is not the primary function of the D-X coil itself. Thus, the correct understanding of a D-X coil's role in refrigeration emphasizes its purpose in cooling air primarily.