30 May 2005


The paper outlines key developments of transcritical CO2 systems, mainly focusing on projects
where SINTEF and Shecco have been or are involved. CO2 as refrigerant in heat pumping systems has
gained interest due to its environmental and safety advantages. The paper reviews applications where
transcritical CO2 systems have been introduced in the market and applications where developments
are ongoing. These include heat pump water heaters, heat pumps for space heating, and mobile air
conditioning and heat pump systems. Both technology and market information is presented. Where
applicable, comparison to alternative system technology will be made.
Initially, a brief summary of environmental issues and an introduction to the particulars of CO2
as a refrigerant is given, before the status and trends within selected areas of the technology are
discussed. It is shown that CO2 is a viable alternative refrigerant for all these application areas.