 An international collaboration project completed in 2015 collected totally 39 examples of R&D-projects and 115 case studies worldwide.The study shows that short payback periods are possible (less than 2 years), high reduction of CO2 emissions can be achieved (in some cases more than 50%).Until the 1990s, the refrigerants were often chlorofluorocarbons (CFCs) such as R-12 (dichlorodifluoromethane), one in a class of several refrigerants using the brand name Freon, a trademark of DuPont.