Chillers use a refrigerant or working fluid in a two-phase refrigeration cycle.
Copper conducts heat up to 8 times better than other metals, such as steel and aluminum. Copper tube is relatively easy to manufacture and form. Copper tube can be easily bent, fitted, and joined. Copper resists corrosion and requires little maintenance, a very important consideration in a closed system with a 20-30 year life expectancy. Copper has the strength required to withstand fluid pressures in large air conditioning systems.