From BIM 6D/7D to operational digital twins: closing the building energy performance gap in tropical buildings- a mixed-methods study in Sri Lanka

Abstract

Buildings and construction are major drivers of global energy demand and energy-related CO₂ emissions, yet operational energy use often diverges from design predictions, creating an energy performance gap (EPG). Building Information Modelling (BIM) has expanded toward lifecycle use, including BIM 6D for energy and sustainability analysis and BIM 7D for facilities management. However, many organisations still struggle to translate design intent into operational outcomes because of poor as-built information, BIM–building energy modelling interoperability issues, weak commissioning-to-operations handover, and fragmented building management system data. Operational digital twins (DTs) are increasingly promoted as a means to connect design and operation by linking information models to real-time data, analytics, and feedback loops. This study develops an expert-validated Sri Lanka-specific framework for integrating BIM 6D/7D with operational DTs to reduce the EPG in tropical buildings. An exploratory sequential mixed-methods design was used. Phase 1 combined policy review and semi-structured interviews with 20 Sri Lankan building lifecycle experts. Phase 2 used a two-round Delphi study with 48 panellists to validate and prioritize 20 statements on barriers and critical success factors, analysed using consensus statistics and the Relative Importance Index. The main barriers are unverified as-built BIM/asset data, BIM–BEM interoperability problems, and insufficient commissioning and controls tuning. The top success factors are capturing control sequences and commissioning evidence, publishing energy-focused digital information requirements for BIM-to-operations continuity, and standardizing asset tagging and FM handover templates. The paper proposes a lifecycle digital thread-to-twin framework and implementation roadmap tailored to tropical buildings and developing-country delivery contexts.