Thermodynamic analysis and multi-objective optimization of the Hefei Advanced Light Facility (HALF) cryogenic system

This study conducts a comprehensive thermodynamic investigation and multi-objective optimization of the cryogenic system for the Hefei Advanced Light Facility (HALF), a critical subsystem responsible for maintaining operational stability and performance. Through systematic application of energy and exergy analysis methodologies, a thermodynamic framework is established to quantify system efficiency and pinpoint primary inefficiency sources. The optimization strategy employs five advanced multi-objective evolutionary algorithms (NSGA-III, MOPSO, SPEA2, MOGOA, MOAHA) for Pareto-frontier exploration, addressing the inherent trade-offs between thermodynamic performance and resource consumption. The dynamic analyses are performed within EcosimPro version 5.4, extended by a dedicated HALF cryogenic library based on CRYOLIB 3.2. Post-optimization results demonstrate a 3.66% relative improvement in exergy efficiency (from 55.79% to 59.45%), accompanied by 5.82% reduction in total power consumption and 31.7% decrease in liquid nitrogen usage. A novel life cycle cost analysis (LCCA) model integrates capital expenditure with operational parameters, revealing 6.7% in lifecycle cost reduction potential over the 30-year service period through optimal configuration selection. The dynamic simulation successfully captures the integrated thermo-fluid and control responses of the HALF cryogenic system, demonstrating robust performance from compression through liquefaction to cryomodule cooling. The proposed methodology establishes new benchmarks for cryogenic system design in particle accelerator facilities, offering both theoretical guidance for thermodynamic optimization and practical strategies for sustainable operation of large-scale scientific infrastructures. The engineering design of the HALF cryogenic system, developed by the RF Superconducting and Cryogenics Group of IHEP, successfully passed the design review on June 15, 2024.