Simulation-based performance analysis of an air conditioning system integrated with a sensible thermal energy storage tank for peak load shaving

Rising residential cooling demand during peak hours places significant stress on both air conditioning systems and power grids, resulting in increased operational costs and reduced system efficiency. This study investigates the integration of a water-based thermal energy storage tank (TEST) with a residential air conditioner (AC) as a strategy for load shifting and performance enhancement under dynamic electricity pricing. The combined simulation and computational fluid dynamics (CFD) analysis revealed that while the coefficient of performance (COP) decreases by up to 9.85% during off-peak charging due to additional compressor load, substantial benefits are achieved during peak hours. The results show COP improvements of 18.7%–41.9% and compressor workload reductions of up to 29.6% were observed during peak cooling periods. The integration of the TEST system resulted in a total daily electricity cost savings of 179.4 Korean won (0.16 USD), representing an 11.6% reduction compared to conventional operation. Additionally, total daily CO₂ emissions were reduced by approximately 10% through effective load shifting from carbon-intensive peak hours to cleaner off-peak periods. These findings demonstrate that water-based TEST can significantly improve the operational efficiency, cost-effectiveness, and environmental sustainability of residential cooling systems. This study presents a practical framework for enhancing the sustainability and economic viability of residential cooling systems in urban environments, where energy demands are increasing and electricity pricing is dynamic.