Conceptual design of a digital twin-enabled building envelope energy audits and multi-fidelity simulation framework for a computationally explainable retrofit plan

Building envelope retrofit plans should be assessed before execution. However, current building energy simulation for retrofit is mainly based on parameters as they are documented instead of in their present conditions. Researchers have applied digital twins (DT) to consider more dynamic processes for such tasks. Researchers need to solve the data exchange issues between the physical and digital worlds to fully use DT in terms of its real-time and multi-fidelity simulation features. They must also solve model updating issues between building information modeling (BIM) and building energy modeling (BEM).

We propose a DT-enabled co-simulation framework for building envelope energy audits and pixel-level simulation. This framework first analyzes inputs and outputs between building physical twin (PT) and DT for energy audits and indicates current technology restrictions to transferring data from PT to DT for building energy simulation. Second, the framework analyzes requirements for as-is simulation-related building parameters and illustrates current research gaps for model updating between BIM and BEM. Third, the framework introduces co-simulation approaches for building energy simulation and indicates how data is exchanged in co-simulation and how simulation results are interpreted for generating retrofit plans. Last, the framework presents current gaps for tracing retrofit plans back to building envelopes and how information is exchanged from DT to PT. Our studies contribute to (1) studying and defining a DT-enabled framework for building energy audits and multiresolution simulation, (2) systematically visualizing the data requirements for this proposed framework, and (3) investigating current technologies and research gaps for such a framework.