The Channel Tunnel requires a cooling system due to heat generated by the high-speed trains. The large capacity chiller system using non-flammable HCFO-1233zd(E) has reduced energy use by 33% compared to the previous system. In addition, the HCFO has a GWP of 1, essentially eliminating any refrigerant emissions contribution to global warming. There are 4 chillers, 2 at each end of the tunnel, with a total capacity of 40MW to maintain the ambient temperature within the tunnel at 25°C.
Each of the 4 chillers has 2000 kg of non-flammable HCFO-1233zd(E). As well as increased efficiency, the chillers installed currently offer 42% spare capacity for future traffic increases. The new chillers were installed during the winter period when free-cooling could carry much of the cooling load, and replaced HCFC-22 chillers installed in 1994. The dual chilled water systems have 60cm diameter pipes in a network about 480 km in length.
source 1 : Energy Manager Today
source 2: Cooling Post