What is the primary function of a cooling tower in large HVAC systems?

The primary function of a cooling tower in large HVAC systems is to remove heat from the building into the atmosphere. In an HVAC system, particularly in large-scale applications, cooling towers play a critical role in managing the heat rejected from the system. They facilitate the cooling of water that is circulated through the building's heating and cooling systems.

When water absorbs heat from the building and its equipment, it returns to the cooling tower, where it is exposed to air. This exposure allows the heat to dissipate into the atmosphere, effectively cooling the water, which can then be recirculated back into the HVAC system to absorb more heat. This process is essential for maintaining efficient operation and comfort within the building, as it helps manage thermal loads.

In contrast, the other options do not accurately represent the function of a cooling tower. Heating water for indoor use, reducing humidity levels, and regulating indoor air quality are not the primary roles of cooling towers; those responsibilities fall to different components and systems within the HVAC framework.