With the new Unichiller 220Tw CO 2, Huber Kältemaschinenbau presents another milestone in environmentally friendly refrigeration technology. The new chiller uses CO 2 as a refrigerant. CO 2 or carbon dioxide (also known as R744) is a natural component of air and has been proven in refrigeration since the 19th century. The colourless gas liquefied under pressure, has no ozone depletion potential (ODP = 0), and has a negligible greenhouse gas potential with a GWP = 1. If, for example, 1 kg of CO 2 enters the atmosphere through a leak in the refrigerating circuit, this is 3780 times less damaging than with the conventional refrigerant R404A. In addition, CO