What is the primary role of a chiller in an HVAC system?

In an HVAC system, the primary role of a chiller is to cool water. This cooled water is then circulated through the building to absorb heat from the spaces being cooled. As the water absorbs heat from the air, it lowers the temperature of the air, thereby providing a comfortable indoor environment.

Chillers play a critical role in larger commercial or industrial systems where they serve as the main source for cooling. The chilled water produced by the chiller is often used in cooling coils or air handlers, which then condition the air that is distributed throughout the building. This process is essential to maintaining efficient temperature control and overall comfort within indoor spaces.

The other options relate to different functions within HVAC systems but do not accurately describe the primary function of a chiller. Heating, air circulation, and humidity control are handled through other components of the HVAC system, such as boilers, fans, and humidifiers, respectively. Thus, correctly identifying that a chiller's purpose is to cool water is key to understanding its role in HVAC systems.