Performance assessment and improvement of district cooling system: A case study of enhancing energy efficiency of hospital buildings

In addressing the performance degradation issue of district cooling systems, although various evaluation methods exist, they either neglect design objectives or focus on independent equipment, overlooking the synergies between devices. Therefore, the study establishes a comprehensive performance assessment framework, encompassing efficiency, environmental impact, economic factors, and technological aspects. The Analytic Hierarchy Process (AHP) and Entropy Weight Method are employed to determine the comprehensive weights for each indicator. In a specific case study, the operational status of an existing district cooling system is assessed, considering collaborative interactions among equipment. A fault tree analysis is applied to scrutinize 13 potential events contributing to system inefficiency and their logical relationships with relevant parameter variations. Based on these findings, specific optimization measures, such as check valve replacement and adjustments to pump and fan frequencies, are recommended. The performance of the optimized system is then re-evaluated, demonstrating substantial improvements with comprehensive performance scores increasing from 18.3 to 27.8 and 29.5, respectively.