The cooling systems of the future tracking detectors of both ATLAS and CMS experiments at the Large HadronCollider (LHC) at CERN will be entirely based on CO_2 refrigeration technology. The system is a boosterrefrigeration system, composed of a two stage primary part with standard R744 equipment and a lowtemperature secondary loop i.e. pumped oil free CO_2 is cooling the tracking detectors and condensed in thelow stage evaporator. The primary refrigeration sub-system installed on surface provides cold R744 (close totriple point temperature of -53℃) to the CO_2 pumped loops installed 100 m underground and rejects the heatexchanged. The process must be reliable and remain stable regardless the amount of heat exchanged, which isexpected to vary throughout the lifetime of the detectors. This paper reviews alternative concepts in the designof evaporative cooling systems using natural refrigerants capable of overcoming the technical challenges.
展开▼
