A chiller is a machine that is used to cool down a space or environment. It works by circulating a refrigerant through a series of coils and fans to reduce the temperature of the air. The most common type of chiller is an air-cooled chiller, which is used to cool down large commercial or industrial spaces. Air-cooled chillers use an outdoor condenser to dissipate the heat generated by the refrigerant, and the cooled air is then circulated through the space. Another type of chiller is a water-cooled chiller, which uses a closed-loop system to circulate water through a heat exchanger to cool down the air. Water-cooled chillers are often used in medical and laboratory settings, as they are more efficient and reliable than air-cooled chillers. In addition, water-cooled chillers are often used in industrial settings, such as factories, where large amounts of heat must be dissipated.