Decision Support System for Sustainable Retrofitting of Existing Commercial Office Buildings
Authors: Anarene Calistus Bengold , Saha Professor Swapan , Davies Professor Peter , Kamrul Dr MD 
Published: August 2024

With more than 60% of the inventory being over thirty years old, commercial office buildings represent a substantial global energy consumer. The Australian government has attempted to lower greenhouse gas emissions through legislation, but the implementation of these efforts has only resulted in annual reductions of 1-3%. It is essential to focus energy-efficient interventions on the stock of current commercial buildings if we are to achieve net zero emissions by 2050. Energy performance, efficiency, and greenhouse gas emissions can all be improved in commercial buildings by reducing energy consumption. According to Climate Works Australia and the IPCC, there is a 30% chance of avoiding current energy use while still reaping net economic benefits. To lessen global warming, the IPCC has also recommended that developed nations, like Australia, reduce emissions by 45% by 2030. Buildings with passive technologies can have better energy efficiency without sacrificing comfort. One of the main tactics for lowering energy consumption and carbon emissions in already-existing commercial buildings is energy retrofitting.
"Providing a machine with a part, or a place with equipment which was not originally present when it was built" is what the Cambridge Dictionary defines as "retrofitting." However, in this context, it refers to any intervention activity that involves modernizing or repurposing the current structure to satisfy an appropriate requirement. Both cases deal with increasing a building's level of sustainability and energy efficiency through renovations.
Multiple combinations of applicable energy consumption-reducing measures that can be applied to retrofit a building present a major challenge to decision-makers in energy retrofit. The evaluation of life cycle cost (LCC) and life cycle analysis (LCA) during retrofits present additional difficulties. LCC and LCA are not used in tandem; additionally, selecting the most appropriate retrofitting strategy or set of measures can occasionally be challenging due to the inclusion of unqualified sustainable technology in listings and selections.
The current study intends to address the problems by creating a strong decision support system (RDSS) that integrates sustainable criteria, or triple bottom line TBLs (environmental, social, and economic benefits), in the energy retrofit decision-making process. This will lessen the difficulties encountered in making decisions that will lead to successful building appraisals. The predetermined objectives are meant to lead to the goal.

Because of various technological alternatives, it may be vital to have a comparison to simplify sustainable technologies (STs) tools using SWOT/multiple criteria in TBL aspects.
Providing an assessment method to merge LCA & LCC to balance environmental and economic performances and determine the impact of the building life cycle on the energy retrofit decision process.
Address the challenges decision-makers encounter in dealing with changes due to building markets and regulations since legislation and public expectation drive sustainable buildings.
To develop and validate a holistic optimum strategic decision model to select the best retrofit alternatives for a particular building which maximizes the sustainability ranking of the building.

Initial research focuses on conducting a life-cycle cost analysis of a commercial office car park building in Sydney, New South Wales. The evaluation includes assessing energy performance through retrofit measures to determine long-term benefits. By using life-cycle cost analysis, the study aims to enhance decision-making in energy assessment.
To examine energy consumption intensity, lifecycle costing, CO2 emissions, and cost efficiency, data will be collected from non-green buildings and one building's envelope will be simulated using the Energy Plus tool. Experimental measurements will be compared to validate simulated models.
The study includes a case study on a 12,000 square meter commercial office building used as a commercial parking facility. Retrofitting activities were initiated on three office rooms, focusing on HVAC, lighting, and equipment improvements, resulting in a 1.9-year payback period, 15% emissions reduction, 25% energy savings, and 23% cost savings.
The subsequent phase involves utilizing various methods such as concept mapping, focus groups, interviews, Questionnaire surveys, and statistical analysis (SPSS) to develop a robust decision support system (RDSS) for sustainable energy retrofits.
The overall goal is to establish a systematic decision support system to aid decision-makers and policymakers in improving energy efficiency in commercial office buildings by implementing passive technologies. The system will also recommend strategies to enhance financial outcomes through smart building operations and management implementations.