An integrated energy-cost model to optimize sustainable retrofit decisions for high-rise residential buildings

Abstract

Sustainable building retrofitting is beneficial for energy conservation, indoor thermal comfort, the reduction of carbon emissions and promotes building sustainability with a low investment and high return. Although numerous retrofit technologies have been developed and most can be employed to improve building energy efficiency, it is hard to determine the appropriate solution for certain climatic zones. From the methodological perspective, building retrofit decision-making methods still face challenges to identify the optimum set of retrofit measures for different climatic conditions, based on the trade-off between energy saving and retrofit cost, considering uncertainties. This study aims to develop a sustainable retrofit decision-making framework for different climatic zones, with uncertainties and uncover the optimum set of retrofit solutions based on local climatic conditions, building features and retrofit cost. This decision-making model improves the current approaches when selecting the best renovation solutions with risk considerations by 1) evaluating the thermal performance of existing residential buildings based on apartment prototypes with specific building characteristics for each climatic zone, 2) developing an optimization model based on practical retrofit measures and local cost, which is integrated with the energy simulation model, and 3) analyzing the uncertainties of retrofit alternatives and investigating their impact on the optimum decision. This framework can provide a practical methodology for the selection of an appropriate retrofit choice in a specific climatic zone while taking risk assessment into account. The local building prototypes are extracted from the summary of an extensive literature review, case studies and prototyping. These prototypes are the foundation of the assessment of building energy performance, which is carried out in the EPC calculator based on ISO standards. The literature review, case studies and deterministic analysis are employed to develop the decision-making model which is integrated with the energy simulation model. This model is based on the optimization of the energy-saving and economic benefits of retrofit alternatives. To make more sensible retrofit decisions, the literature review and uncertainty analysis is adopted to identify, quantify and mitigate the risk involved in the building retrofit decision-making process. Through this decision-making methodology, the optimum retrofit solution with the appropriate strategies and most suitable energy-saving approach can be identified for various climatic regions. Uncertainty analysis pinpoints the quantitative impact of uncertain parameters in the selection of alternative solutions and highlights the critical factors that result in uncertain range and probability distribution of retrofit decisions. These findings can contribute to sustainable building retrofit knowledge and practice by 1) making an effort to explore a new sustainable retrofit decision-making method to select the best renovation solutions for each climatic zone, 2) integrating risk assessment with decision-making to identify a sensible and reliable strategy, and 3) providing a simple way for decision-makers to find an energy-efficient and cost-effective retrofit solution based on their own goals and climatic conditions.