Energy, environmental, economic retrofit framework for low-rise office buildings in Shanghai: a multi-objective decision-making approach

Abstract

Office buildings comprise of 25% and also accounts for the most significant energy consumption in the commercial building sector in Shanghai. Within this, existing low-rise office buildings (LOBs, below six floors) make up over 50% and are barely adaptable to the present climate variation. On the other hand, it is projected that building energy consumption will increase by 1.7% annually until 2025 along with other reasons. Hence, it is imperative to retrofit these existing LOBs to reduce energy consumption and meet with sustainable building energy use intensity (EUI) standards. However, there is no standard retrofitting framework for this building typology. At first, it is established that specific building characteristics alter the optimal retrofit decision. Construction year, plan form and building orientation are revealed via correlation and cluster analysis to be the most prominent building features for LOBs in Shanghai. As a result, four prototypical buildings representing the existing LOBs were identified using the prominent building characteristics as key classification indexes. The prototypical buildings include 1 rectangular type built before 2005, 2 rectangular types built within 2005-2015 and 1 square built within 2005-2015. These prototypes provided the underlying structure for modelling a retrofitting framework for LOBs in Shanghai. Energy, environmental, economic retrofit framework (3ERF) was established by an integrated approach combining the statistical assessment of the benefits of the specific retrofit measures, life cycle cost (LCC) and cluster analysis. The parametric study relating the different retrofit measures to their impact on building EUI was performed using Integrated Environmental Solutions Virtual Environment (IES-VE) simulation software, a building performance analytical tool. A simplified LCC assessment was performed to evaluate the energy and economic prospects of a combination of 12 different retrofit measures. By defining the cost-efficient zone around the minimum LCC, a set of combinatorial retrofit strategies are obtained. Using the total saved Greenhouse Gas (GHG) emissions as an environmental indicator, the combinatorial retrofit strategies are compared to provide the optimum solution. Furthermore, the 3ERF is adopted to specify suitable retrofit solutions to achieve the different EUI targets in Shanghai. Overall, the usefulness of the proposed prototypes and 3ERF can provide the pre-decision framework to guide different building stakeholders on suitable retrofit strategies based on their energy, environmental and economic (3E) priority for the whole cycle of LOBs.

Date of Award	16 Jul 2021
Original language	English
Awarding Institution	Univerisity of Nottingham
Supervisor	Wu Deng (Supervisor), Sung-Hugh Hong (Supervisor) & Yue Tang (Supervisor)