What is the role of a "chiller" in HVAC systems?

The role of a chiller in HVAC systems is fundamentally to remove heat from a liquid through a refrigeration cycle. This process begins by circulating a refrigerant within the chiller system, which absorbs heat from the liquid, typically water, that is pumped through the system. As the refrigerant absorbs heat, it evaporates and changes into a gas. Subsequently, this gas is compressed, increasing its pressure and temperature, before it passes through a condenser where it releases the absorbed heat to the outside environment and condenses back into a liquid.

This continuous cycle effectively lowers the temperature of the liquid being cooled, which can then be circulated throughout the building—enabling air conditioning or cooling of equipment. The ability of chillers to manage heat transfer in this way is critical for maintaining desired indoor air temperatures and ensuring comfort during warm weather conditions.

In contrast, the other options pertain to different functions not associated with chillers. One option involves redistributing hot air, which does not align with the primary function of a chiller. Another option suggests the humidification of air, a process typically managed by separate devices or systems like humidifiers rather than chillers. Lastly, circulating hot water is related to heating systems rather than cooling, where a chiller operates