CO2 is commonly used as a ‘clean’ liquid refrigerant in supermarkets. Now, researchers at the École Polytechnique Fédérale de Lausanne (EPFL) have tested it to determine if it could also be used to transport the energy needed to heat and cool buildings, particularly in urban settings. As their prototype demonstrates, a heating and cooling distribution network that uses CO2 could lead to over 80 per cent in final energy savings, writes the EPFL in a press release.
Transporting CO2 between buildings has a number of advantages, as the researchers explain. It circulates at a temperature of around 15 degrees Celsius, which is close to the temperature of underground soil and thus limits the need to insulate the pipes. And as there is no risk of freezing, the pipes could be installed under sidewalks. The pipes themselves could also be smaller in diameter than pipes in a water-based network.
According to the EPFL, the initial cost of such a system would be around CHF 27 to 35 million and would become profitable after just four to six years of going online.
The pilot facility in Geneva was developed and operated in collaboration with the Geneva utility company Services Industriels de Genève (SIG) and the Zurich engineering firm Amstein+Walthert. The project received financing from the Commission for Technology and Innovation (CTI).