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Replacing An Air-con Refrigerant

Challenge

Develop a drop-in replacement for a powerful greenhouse gas refrigerant.

Problem

Air-conditioning units rely on refrigerants to operate efficiently. These are typically substances that undergo a reversible phase change (eg gas to liquid), have good thermodynamic properties, and are unreactive chemically and safe to humans and the environment. The market for such substances is worth around US$5 billion a year.

Early high-performance refrigerants such as chlorofluorocarbons were shown to be damaging to the Earth’s ozone layer. Their replacements – hydrofluorocarbons – have been shown to have very high global warming potentials. The EU has passed the Mobile Air Conditioning (MAC) Directive. It stipulates that as of 2011, refrigerants in new vehicle types cannot have a Global Warming Potential (GWP) greater than 150. As of 2017, this will apply to all new cars. The refrigerant currently used in automotive air conditioning, R-134a, will be phased out in automobiles.

Solution

A replacement for the common automotive air-conditioning refrigerant, R134a (1,1,1,2-tetrafluoroethane, global warming potential 1430 C O2e) has been identified in hydrofluoroolefin 1234yf (2,3,3,3-tetrafluoropropene, GWP 4). The replacement means minimal switching costs for end-users (automobile manufacturers). Honeywell and DuPont are jointly producing 1234yf and hold the majority of global patents.

Benefits

335 times lower global warming potential than current refrigerant
400 times shorter atmospheric lifetime
Near drop-in replacement

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