Retrofitting and operational performance analysis of photovoltaic,energy storage, direct current, and flexibility (PEDF) integrated low-carbon cooling systems in existing public buildings

The photovoltaic, energy storage, direct current, and flexibility (PEDF) integrated low-carbon cooling system represents a critical pathway for decarbonizing existing buildings. Targeting the retrofit demands of low-carbon renovation of existing buildings, this study overcomes prior PEDF research limitations focused on new buildings and low-power devices by developing a “generation-consumption-storage-regulation” integrated low-carbon cooling system. Through engineering implementation in a public building, the PEDF integrated low-carbon cooling system demonstrates a comprehensive energy efficiency ratio of 4.5, with a unit cooling cost of 0.126 yuan/kWh, and operational carbon emission intensity of 0.443 kg/kWh, achieving a 31% reduction compared to municipal grid benchmarks. Further analysis reveals suboptimal operational load rates for the flexible bidirectional converter and the transformer. Future research should optimize converter capacity allocation based on renewable energy utilization requirements to minimize design redundancy and enhance system cost-effectiveness.