Increasing the energy efficiency of existing buildings is the major strategy to reach carbon neutral targets, given that the building sector is a major emitter. In particular, one major part of building energy usage is the building heating, ventilation and air-cooling system, which are highly depending on the thermal performance of building envelope and increase the challenge of selecting optimal packages of energy efficiency measures. This paper thereby presents a method for optimizing the building envelope and heating, ventilation and air-cooling system. The simulation-based NSGA-III approach developed in this paper is based on coupling the dynamic simulation models created in EnergyPlus software with the non-dominated sorting genetic algorithm, as the engine that performs an optimization process. A large domain of energy efficiency packages combined with heating, ventilation and air-cooling systems and building envelope are investigated to minimize energy consumption, retrofit cost and thermal discomfort in indoor environments, which including ideal loads air system, four pipe fan coil system and variable refrigerant flow system, insulation materials and insulation thickness for external walls and roof, different types of external windows, and window-wall ratio. An office building in Chongqing was chosen as a case study to demonstrate the practical implementation of the proposed method. The results show that the four pipe fan coil system was superior in the diversity and performance of the Pareto front. Then, the optimal packages were generated by a synthetic method, which have 58.57 kWh/m2 of energy consumption, 30.76 CNY/m2 of retrofit cost and 40.67 % of the percentage of thermal discomfort hours. The results also indicate that the yearly energy savings rates are 17.30 %, 23.05 % and 21.10 % separately for ideal loads air system, four pipe fan coil system and variable refrigerant flow system after performing optimization. These results highlight the importance and necessity of performing an optimization procedure for existing buildings to select the optimal retrofit measures.

中文翻译：

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办公楼改造中围护结构与暖通空调系统的综合优化


鉴于建筑行业是主要排放源，提高现有建筑的能源效率是实现碳中和目标的主要策略。特别是，建筑能源利用的一个主要部分是建筑供暖、通风和空气冷却系统，其高度依赖于建筑围护结构的热性能，增加了选择最佳能效措施组合的挑战。因此，本文提出了一种优化建筑围护结构和供暖、通风和空气冷却系统的方法。本文开发的基于仿真的 NSGA-III 方法基于将 EnergyPlus 软件中创建的动态仿真模型与非支配排序遗传算法相结合，作为执行优化过程的引擎。研究了与供暖、通风和空气冷却系统以及建筑围护结构相结合的大量能效包，以最大限度地减少室内环境的能耗、改造成本和热不适，其中包括理想负荷空气系统、四管风机盘管系统和变量制冷剂流动系统、外墙和屋顶保温材料和保温厚度、不同类型的外窗、窗墙比。选择重庆的一座办公楼作为案例研究来展示该方法的实际实施。结果表明，四管风机盘管系统在Pareto前沿的多样性和性能方面均具有优越性。然后通过综合方法生成最优包，其能耗为58.57kWh/m2，改造成本为30.76元/m2，热不适小时百分比为40.67%。 研究结果还表明，理想负荷空气系统、四管制风机盘管系统和变制冷剂流量系统经过优化后，年节能率分别为17.30%、23.05%和21.10%。这些结果凸显了对现有建筑进行优化程序以选择最佳改造措施的重要性和必要性。