Energy, cost, and environmental assessment of low-GWP refrigerant replacement pathways for water-cooled chillers

Refrigeration and air-conditioning systems contribute substantially to global energy consumption and greenhouse gas emissions, making the replacement of refrigerants with high global warming potential essential for water-cooled chillers. This study compares three refrigerant replacement pathways: R1233zd(E) replacing R134a, R513A replacing R134a, and R514A replacing R123. Cooling capacity, compressor power, and coefficient of performance were measured at load ratios ranging from 25% to 100%. The experimental results were subsequently converted into capacity-normalized annual electricity consumption, life-cycle environmental impacts, and life-cycle costs over a service life of 15 years. The three replacement pathways reduce annual electricity consumption by 5.18%, 11.10%, and 5.03%, respectively, while decreasing life-cycle greenhouse gas emissions by 53.9%, 34.5%, and 10.6%, respectively. R1233zd(E) provides a stable improvement in the coefficient of performance and achieves the greatest reduction in greenhouse gas emissions. R513A exhibits the strongest annual energy-saving potential under partial-load operating conditions, whereas R514A maintains cooling capacity while reducing both greenhouse gas emissions and ozone-depletion impacts. Although all three replacement pathways increase life-cycle costs, the cost–environmental benefit matrix identifies the replacement of R123 with R514A as the most balanced near-term option. The proposed framework provides a quantitative basis for selecting and deploying low-global-warming-potential refrigerant replacement pathways in water-cooled chillers.