Towards resilient building performance: definitions, frameworks, and metrics

Abstract

In recent years, resilience has become a relevant issue in the context of building performance, owing to the diverse future events, which includes climate change, extreme weather events, energy supply disturbances, and pandemics. In traditional building designs, building performance is typically estimated under a fixed set of assumptions. However, significant external factors can impact building performance during its operational phase but have not been considered by designers. Failure to protect building performance against these changes can lead to serious short- and long-term challenges, such as fails in meeting the demands of building occupants. Therefore, the resilience of building performance needs to be investigated such that its sensitivity to external factors, like climate change, is reduced.

In this thesis, a building is defined as resilient if it is able to prepare for, absorb, adapt to, and recover from disruptive events. Despite the potential of resilient building designs and their growing interest, an agreed-upon definition for resilience in the context of building performance requires further research, along with the development of methodologies for resilience quantification. This situation is partly due to the polysemic background of the resilience definition that is interpreted differently in various fields.

This thesis investigates resilience in the context of building performance and develops methodologies, frameworks, and metrics for the quantification of resilience on the building scale. This paper-based thesis first focuses on adapting the existing resilience definitions to the context of building performance. This procedure begins with four questions related to the concept of resilience, which are resilience of what? resilience to what, resilience in what state, and resilience based on what? The answers to these questions allow designers to establish the key parameters for a resilient design.

Resilient systems usually have a combination of attributes that influence resilience and contribute to the quantification of resilience level through the derivation and validation of a function form in regard to functionality and time. The second research activity identifies robustness and flexibility as two important attributes of resilient building design and develops methodologies for their quantification.

As the final step, a methodology is developed, focusing on a framework for the quantification of resilience itself. This step introduces a single metric for thermal resilience quantification in the scale of buildings. The metric is implemented for resilience labelling. In the quantification methodologies,

IDA Indoor Climate and Energy software (IDA-ICE) is used as a building performance simulation tool, and MATLAB is used as a numerical analysis tool. The developed quantification methodologies were tested on a case study of a Norwegian single-family house.

The results of this research led to seven peer-reviewed papers, in which four comprise the core of the thesis and are listed as primary papers. The other three papers, which are from collaborations with other researchers, are listed as supporting papers in this thesis. The results highlight the suitability of the proposed methodologies and metrics for the quantification of resilience and its attributes. For example, for the considered case study building in Norway, it has been shown that upgrading building design from the current minimum design to a passive design has a significant impact (71% improvement) on the thermal resilience against power failure during winter. Furthermore, the results of the case study implied that various building designs with the same energy consumption can behave differently when facing uncertainties in the future, such as changes in weather conditions, occupant behaviour, and energy prices.

Uncertainties of the future highlight that the evaluation of energy performance by itself will not be enough in the energy performance certificates in the near future. Therefore, the evaluation of other concepts, such as building resilience (robustness and flexibility), is also needed. This thesis takes one step forward in this regard by developing metrics, quantification frameworks, and methodologies for the evaluation of robustness, flexibility, and resilience that can be easily used by architects, building designers, decisionmakers, etc. to benchmark different building designs and technologies from these perspectives.