Speaker
Description
In order to meet the challenging thermal and environmental conditions of the ATLAS and CMS upgraded detector after LS3, a next-generation CO$_2$ evaporative cooling system has been developed. The new infrastructure is built around a modular design, consisting of multiple independent cooling units operating in parallel. Each module includes a dedicated cooling plant and a high-pressure accumulator, both located in the respective service caverns of ATLAS and CMS. These systems are responsible for supplying cold, saturated liquid CO$_2$ to the detectors through a network of transfer lines and manifolds.
The liquid CO$_2$, maintained at temperatures as low as -54 °C and pressures reaching 100 bar, will circulate in a two-phase flow regime. Compared to the previous systems used at the LHC, the new setup offers increase in both cooling capacity and operational volume.
As a result, substantial design adaptations were required in the CO$_2$ systems and its full infrastructure. The well-established 2PACL cooling concept was scaled up, incorporating larger plant dimensions, a reimagined accumulator principle, and industrial-grade piping and manifold enlargement.
All of this required a completely different approach to the construction of the cooling systems, passing through a number of large industrial contracts, worth several MCHF. Following up on last year's presentation, which addressed the preparation for outsourced production and CE marking, this talk will serve as a complementary overview—focusing on the lessons learned during the detailed production phase of the multiple units composing this large-scale mechanical system. It will cover the challenges faced, solutions implemented, and practical experience gained throughout the manufacture and reception of multiple CO$_2$ cooling units, including plants, accumulators, and distribution manifolds. The experience of large-scale outsourced production, somehow usual for the serial production of detector module components, has never been faced in our environment for such large and complex systems, and provides useful indications for the design and procurement organization of large-scale infrastructural mechanical components of future experiments.
