A decision tool for selecting low-carbon refurbishment solutions for multi-storey residential buildings in Hong Kong

Abstract

The pressure to reduce greenhouse gas (GHG) emissions has become increasingly obvious due to the need to alleviate the impact of climate change. As the second largest GHG emitter in the world, the building sector should play an active role in reducing GHG emissions. Particular attention should be directed to existing buildings not only because of the amount of emissions caused by inefficient buildings but also due to the existence of a variety of sustainable refurbishment solutions for different levels and stages of building refurbishment. The emission reduction performance of different sustainable refurbishment options may vary enormously as a result of different building design conditions. With the majority of residential properties being high-rise buildings, the most suitable sustainable refurbishment options for a sub-tropical city like Hong Kong are yet to be fully investigated. The opportunity to reduce emission may not be high without a tool to help the owners, occupants and consultants to assess the emission of different refurbishment solutions for multi-storey residential building.

The aim of this research has been to develop a systematic decision tool to identify suitable sustainable refurbishment solutions for multi-story residential buildings in subtropical regions like Hong Kong and to calculate the CO2emission reductions of these solutions. The research began with a comprehensive literature review of the existing sustainable refurbishment approaches. The results of this literature review formed the basis for a preliminary screening according to local climate and buildings features. Interviews with experts and questionnaire surveys with residents were carried out in order to confirm the applicability of the proposed approaches. Then, based on a case study, this research established a set of methods, through literature review and energy simulation, to calculate the CO2 emission reductions achievable by sustainable refurbishment. With the setup of criteria for identifying applicable refurbishment solutions, method of calculation of CO2 emission reductions and parameter input/output and user interface design, a decision tool was developed for sustainable refurbishment. Finally, a series of interviews was conducted to validate the major research outcomes.

In this study, a residential building is divided into two zones, the common area and those occupied by owners/tenants. This study further identifies possible sustainable refurbishment solutions for each area, which can provide stakeholders with a variety of options for launching sustainable refurbishment projects. Moreover, a theoretical framework for emission assessment, consisting of system boundary and calculation methods, is also proposed in this study, which can provide better calculation of emission reductions as a result of various sustainable refurbishment solutions. The most significant outcome of this project is a decision tool which can generate a set of sustainable refurbishment solutions and calculate CO2 emission reductions according to the architectural features input by users. With the function of identifying the approaches for reducing CO2emission, owners and occupants of existing residential buildings can minimize the CO2emissions of their properties through refurbishing some of the building components in a sustainable manner.