PassivBIM: Enhancing interoperability between BIM and low energy design software

• The Industry Foundation Classes schema is analysed and extended with an energy domain.
• Energy concepts in the extension originate from the Passive House Planning Package (PHPP).
• The extension is used to develop a system called PassivBIM.
• PassivBIM can process geometry from IFC files, optimise a buildings performance and export data back to PHPP.
• PassivBIM is validated with case studies, then developed to inform design decision making.

The process of building design is currently undergoing some major changes. In an attempt to mitigate climate change, the design of more sustainable buildings is advocated by the UK government. Furthermore, standalone design methods are being replaced with the concept of Building Information Modelling (BIM). The adoption of BIM has been documented to result in many benefits, which range from time to cost savings. During the initial planning stages, building performance simulation (BPS) can be used to inform design decisions. Data can be exchanged between BIM and BPS tools using data transfer schemas such as the Industry Foundation Classes (IFC). The IFC schema lacks an energy domain, and as a result, an extension is proposed in this paper. This contains energy concepts from a BPS tool called Passive House Planning Package (PHPP). The extended schema was developed by way of an externally coupled Java tool, which facilitates the transfer of data, and informs the building design decision-making process. The process of geometry extraction has been validated with several case studies, which are based on certified Passivhaus buildings in Hannover Kronsberg, Germany and Ebbw Vale, Wales. The amount of error is acceptable, and it is mostly due to differences in the initial BIM model setup, not due to the processing of IFC files.