In October 2016, the "Kigali Amendment" to the Montreal Protocol was adopted. It states
that it is obligatory to phase down the production and consumption of hydrofluorocarbons (HFCs),
which has set an important global trend in refrigerants. In developed countries, the target is an
85% reduction by 2036 from the respective reference years (2011-2013). As further enforcement of
tougher regulations for HFC reduction can be expected, there is an urgent need to start using low
global warming potential (GWP) refrigerants. From the viewpoint of product life cycle, it will
become increasingly unlikely for centrifugal chillers using HFC refrigerants to be introduced.
Under such circumstances, Mitsubishi Heavy Industries Thermal Systems, Ltd. launched the ETI-Z
series in September 2015 using HFO-1233zd(E) with a GWP of 1, and the GART-ZE/ZEI series in
April 2017 using HFO-1234ze(E) with a GWP of
