Channel Tunnel's new refrigeration system achieves energy savings of over 30%

With a length of 50.5 km, the Channel Tunnel has connected England to France since 1994. It is the longest undersea tunnel in the world. Because of the heat generated by high-speed trains, the temperature of the tunnel could reach 50 °C without a refrigeration system. In order to keep the temperature under 30 °C during summer, an initial system with eight R22 chillers was installed.

European Regulation No. 2037/2000 – which has been replaced by Regulation No. 1005/2009 – prohibits the use of recycled HCFCs, including R22, in the maintenance and servicing of all equipment from January 1, 2015 (for further information, see the IIR Regulation file concerning the European Regulation No. 2037/2000).

This is why, in 2016, tunnel operators Eurotunnel decided to replace the R22 chillers with four Trane Series E CenTraVac chillers which use HFO R1233zd(E). These chillers incorporate a direct drive centrifugal compressor with a refrigerant economiser for improved efficiency. The chillers were replaced during the winter period, when free-cooling via the plant's dry-coolers carries much of the cooling load.

Each chiller is charged with around 2,000 kg of R1233zd(E). This HFO refrigerant has a GWP of 1 and is non-flammable. After the first season of operation, initial results show that the new system has achieved energy savings of 33% in 2017. They also reveal an energy consumption of 4.8 GWh, resulting in savings of approximately EUR 500,000.

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