Carbon dioxide refrigeration

Although demonised as a greenhouse gas, carbon dioxide could have a future as a more environmentally-friendly alternative to HFCs and CFCs for refrigeration.

Engineers developing technologies that use carbon dioxide as a refrigerant instead of conventional, synthetic chemicals will meet at Purdue University, Indiana, this month to discuss the latest research. The event is the annual meeting of the Carbon Dioxide Interest Group, an international organisation of engineers from academia and industry promoting carbon dioxide as a refrigerant.

The conference will include talks about applications ranging from soft drink vending machines to portable air conditioners used by the US Army for a variety of roles, such as cooling troops and electronic equipment. Talks also will cover the use of carbon dioxide to run “heat pumps,” which operate like air conditioners in reverse, to warm swimming pools and homes, said Eckhard Groll, a Purdue professor of mechanical engineering who is organising the conference.

Although carbon dioxide is a greenhouse gas, conventional refrigerants, hydrofluorocarbons chlorofluorocarbons (HFCs and CFCs), cause about 1,400 times more global warming than the same quantity of carbon dioxide. The tiny quantities of carbon dioxide that would be released from air conditioners would be insignificant compared to the huge amounts produced from burning fossil fuels for energy and transportation, Groll said.

“Carbon dioxide has unique characteristics that make it an ideal green-technology alternative for certain applications in refrigeration and heating,” said Groll, who is developing carbon dioxide-based air conditioning systems as part of his research at Purdue’s Ray W. Herrick Laboratories.