Uncertainty analysis of envelope retrofits for existing residential buildings in underdeveloped areas: A case study of Daokou, China

• Published in: Energy and buildings 2023-04, Vol.284, p.112828, Article 112828
• Main Authors: Wu, Di, Zhang, Taoyuan, Zhang, Jiqiang, Yue, Chao, Lu, Jifu, Zhang, Yike, Fu, Mengze
• Format: Article
• Language: English
• Subjects: Building envelope; Global sensitivity analysis; Retrofit; Uncertainty analysis; Underdeveloped areas
• ISSN: 0378-7788
• DOI: 10.1016/j.enbuild.2023.112828

•The uncertainty inputs are characterized to reflect the impacts of low technology and economic levels.•An orthogonal experiment and Latin hypercube sampling are combined in the uncertainty analysis.•The standard regression coefficient and treed Gaussian process are used in the global sensitivity analysis.•The uncertain impact on annual heating, cooling and total energy consumption and the envelope energy-saving rate are analyzed.•The retrofit scene with the best energy-saving effect is always accompanied by the highest uncertainty. Current envelope-related uncertainty analysis (UA) focuses mostly on the physical properties of materials. However, the uncertainties of retrofit strategy selection, building element selection and construction quality are especially significant in underdeveloped areas due to their low economic and technical levels. To obtain more reliable energy analysis results and to correctly support decision-makers, a new UA method combining an orthogonal experiment (OE) and Latin hypercube sampling (LHS) is proposed to investigate the uncertain outputs caused by the three mentioned aspects. Furthermore, important factors affecting the uncertain outputs are screened by two global sensitivity analysis (GSA) methods: the standard regression coefficient (SRC) method and the treed Gaussian process (TGP) method. The UA results show that considering the uncertain inputs, the envelope energy-saving rates fluctuate from 46 %∼65 %, 70 %∼92 %, 48 %∼67 %, and 71 %∼90 % separately for the four typical retrofit scenes. The retrofit scene with the best energy-saving effect is always accompanied by the highest uncertainty. The GSA results show that the top three sensitive factors account for approximately 80 ∼ 100 % of the output variance. Infiltration and wall insulation thickness are the two most important factors for energy consumption in most cases. The results of the SRC and TGP methods are in general agreement, while TGP has the advantage of distinguishing the nonlinear relationship between glazing type and cooling energy. Therefore, it is advisable to apply design schemes that can make a trade-off between energy savings and robustness when performing envelope retrofits in underdeveloped areas.