CO₂ as working fluid - technological development on the road to sustainable refrigeration

The refrigeration society has made a tremendous development of technology based on CO₂ as refrigerant since the reintroduction around 1990. CO₂ has become an important alternative in replacing the environmentally harmful CFC-, HCFC- and HFC refrigerants. The paper highlights some of the elements in the development, why it started, barriers and some reasons for the success. Development within some applications is discussed, as well as development and availability of components. Finally, some current developments and remaining challenges are considered.