The European Organization for Nuclear Research


Daikin has recently been involved in the commissioning of two new air-cooled chiller units at CERN. Specifically, the project involved the Linear accelerator 4, also known as Linac4. The two units have been installed to provide the cooling needed so the equipment in the facility can properly function.


Total cooling capacity: 1312 Kw



The Linear accelerator 4 (Linac4) is designed to boost negative hydrogen ions to high energies and has been the source of proton beams for the Large Hadron Collider (LHC) since 2020.

It is 86 metres long and located 12 metres below ground. Beams began to be produced in 2013 and the milestone energy of 160 MeV was reached in 2016, after the commissioning of all the accelerating structures. During the long shutdown 2019–20, the Linac4 replaced Linac2, which had previously accelerated protons to 50 MeV.

Daikin chillers have been chosen to provide the Linac4 facility, and the equipment in it, with the necessary cooling so experiments can be carried out, ensuring proper and safe functioning of the equipment.

So, other than energy efficiency and low environmental impact – that are very important to CERN – reliability was a key aspect.


The units installed to provide cooling to the above-mentioned facility are two air-cooled with Daikin inverter screw compressors using refrigerant R-1234ze. The units are characterized by very low GWP (7) thanks to the HFO refrigerant and low direct and indirect CO2 emissions.

The overall energy efficiency levels offered by this Series are very high. That is something made possible by the 3rd generation Daikin in-house designed inverter screw compressor, which offers a new screw profile, optimized to operate very efficiently with R-1234ze as well. Of course, that elevates the performances of the TZ Series in terms of energy consumption.

Daikin screw compressor, besides being well-knows for efficiency, have been installed all over the world for over 20 years and offer great reliability. Differently from a standard screw compressor, Daikin screw compressor uses one main screw meshing with twin star rotors to produce volume matching compression cycle. Due to the main rotor, balanced in both radial and axial direction, the compressor bearing has extremely high reliability. Daikin single screw compressor, then, has only three moving parts. As a result of that, the possibilities of failure are reduced, and operation costs are kept low. Therefore, its life span can be longer than other screw compressors.

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