Study On Energy Efficient Design Of Double-Skin Facades

As a new facade style, Double-Skin Facade (DSF) has been broadly used in European office buildings during the last twenty years. And some of these buildings achieved high energy efficiency, comfortable indoor environment and good indoor air quality with it. In the last few years, DSF was introduced into some high-class office buildings in China, but their energy performance are not satisfactory.As most domestic designers have little knowledge of the exact thermal performance of DSF, some preliminary introductions are provided in the first part, including simple calculation methods and practical experiences which can be used to predict thermal performance in conceptual or schematic design phase. Then, domestic and foreign DSF practices are compared, and big gaps are found in two levels: interdisciplinary cooperation during design and the use of design tools. In this paper, many typical DSF examples are gathered, and summary is made for type, construction, HVAC system, and automatic control, etc. However, the climates of different Chinese cities vary from that of Europe cities. Current simple copies of foreign designs and productions lead to many problems, since climate has heavy influence on DSF's highly dynamic thermal performance. So far, domestic simulation work has been basically restricted to using CFD or other steady calculation method to predict performance in worst conditions in summer and winter, which cannot meet the demand in practice for predicting the impact of DSF on annual load and energy consumption of the building. Therefore, dynamic thermal simulation with IES is adopted in this paper to model and calculate building performance in difference climates (Beijing, Shanghai and Guangzhou), different building floor plans (core, corridor and atrium style), different facade orientation (south, north, east and west) and different facade type (box DSF and active DSF, openable and unopenable single skin facade are used for references). Simulation results are analyzed based on indices of accumulative cooling/heating load, cooling/heating equipped Capacity, indoor thermal comfort and indoor air quality, and can serve as reference for selecting proper facade type in early design phases. In later phases, the selected DSF type should be optimized for energy efficiency. Some important factors are raised for this work. And using single parameter analysis method, sensitivities of these factors are performed with dynamic simulation.In the end, outlooks for research areas of DSF energy efficient design are listed, including key parameters (for example, airflow resistance) study, comparison between simulation results and field test data, different combination of DSF and HVAC systems, DSF and building system control strategy, and long-term cost analysis considering local energy prices, etc.