A chiller is an important component of an HVAC system. It works by circulating a refrigerant through a closed loop system, which absorbs heat from the air and transfers it to the refrigerant. The refrigerant is then compressed, causing it to become hot and release the heat into the atmosphere. The refrigerant is then cooled and circulated back through the system to absorb more heat. This process is repeated until the desired temperature is reached. Chiller systems are used to cool large areas, such as commercial buildings, and can be used in conjunction with other HVAC components, such as fans and air handlers, to provide a comfortable environment.