With the increase in the energy demands for heating, cooling, and electricity for buildings, the distributed energy system (DES), which is driven by renewable energy and natural gas, has become an economic and environmentally beneficial option for energy generation and supply. This paper presents a method for the integrated optimization of component capacity and annual operation of DES. In the outer cycle optimization, the capacity of energy generators and energy storages is optimized together to match the fluctuating energy demands of the whole year. In the inner cycle optimization, the hourly operation of energy generators and energy storage is managed following the operation strategy that reduces the exergy loss rate.

Case studies of DES design under different grid connection modes for an office building demonstrate the feasibility and flexibility of the proposed method. A traditional centralized system is employed as a baseline of performance, and two other capacity design methods are utilized for comparison. Results show that DES designed by the proposed method reduces carbon emissions by 0.170 kg/kWh, energy consumption by 0.392 kWh/kWh, and operation costs by 0.123 CNY/kWh, on average. In contrast to DESs designed by other methods, the performance of these parameters is improved by 0.019 kg/kWh, 0.078 kWh/kWh, and 0.031 CNY/kWh, respectively. Moreover, the DES design exhibits advantages in exergy saving, uncertainty resistance, and power grid independence.

随着建筑物供暖，制冷和电力的能源需求的增加，由可再生能源和天然气驱动的分布式能源系统（DES）已成为能源生产和供应的一种经济和环保的选择。本文提出了DES组件容量和年度运行的集成优化方法。在外循环优化中，同时优化了能量发生器和储能器的容量，以适应​​全年波动的能源需求。在内部循环优化中，按照降低火用能损失率的运行策略来管理能量发生器和储能的每小时运行。

通过对办公大楼在不同网格连接模式下进行DES设计的案例研究，证明了该方法的可行性和灵活性。采用传统的集中式系统作为性能的基准，并使用其他两种容量设计方法进行比较。结果表明，通过该方法设计的DES平均可减少碳排放量0.170 kg / kWh，能耗0.392 kWh / kWh和运行成本0.123 CNY / kWh。与通过其他方法设计的DES相比，这些参数的性能分别提高了0.019 kg / kWh，0.078 kWh / kWh和0.031 CNY / kWh。此外，DES设计在节能，抗不确定性和电网独立性方面均具有优势。