Research on the design optimization of energy storage system in Photovoltaic Energy storage Direct current and Flexibility (PEDF) system in buildings

The Photovoltaic Energy storage Direct current and Flexibility (PEDF) system has attracted significant attention in recent years. In this system, charging piles, air conditioning, building energy storage, and photovoltaic are connected to the direct current bus, with flexible adjustment capabilities. The increasing presence of flexible loads complicates the calculation of electrical balance in buildings. Building energy storage is a crucial component of the PEDF system, and its storage capacity (kWh) and power (kW) are parameters that need to be determined during the design phase. This study focuses on the energy storage system of PEDF, considering both electricity and cooling storage methods, with the goal of optimizing capacity and power for economy. A dual-layer optimization model of “operational-design optimization” is proposed. The operational optimization model enables the calculation of power supply and demand balance involving multiple flexible loads over the entire year of 8760 hours. In the design optimization model, equipment investment is considered based on the operational optimization model, and particle swarm optimization (PSO) is employed to achieve the design optimization of energy storage system. This study uses a Shenzhen office building as a case study, demonstrating that the installation of battery and cooling storage facility can enhance system economic efficiency, while the scale of photovoltaic installation and time-of-use tariff significantly impact the design of building energy storage solutions.