Heat pump the brand name Freon, a trademark of DuPont. Its manufacture is now banned or severely restricted by the Montreal Protocol of August 1987 because of the damage that CFCs cause to the ozone layer if released into the atmosphere. One widely adopted replacement refrigerant is the hydrofluorocarbon (HFC) known as R-134a (1,1,1,2-tetrafluoroethane). Heat pumps using R-134a replaced R-12 (dichlorodifluoromethane) and have similar thermodynamic properties but with insignificant ozone depletion potential and a somewhat lower global warming potential. Other substances such as liquid R-717 ammonia are widely used in large-scale systems, or occasionally the less corrosive but more flammable propane or
The Montreal School the texts. The Montreal School The Montreal School, as its name suggests, is a school of thought in the field of organizational communication. It was initiated by James R. Taylor and colleagues in the Department of Communication at the Université de Montréal. It origin can be traced back to the introduction in 1987 of a new doctoral program bringing together three major French-language universities in Montreal, the Université de Montréal, the Université du Québec à Montréal, and Concordia University. The Montreal School has had, and continues to have, a global resonance in Europe ) as well as on the American