Build clean models before exporting the gbXML file and avoid integration errors before they happen, yielding predictably good results across many applications.
The AEC industry is familiar with creating building loads for systems sizing and then producing energy models with the Performance Rating Method (ASHRAE 90.1 or NECB). Although these project deliverables are typically done independently from each other without any integration to the project’s architectural and MEP systems design.
The building loads are produced from an early snapshot of the building’s form and features, then the compliance energy model acts as an auditing tool when the design is complete. A framework that incorporates these familiar industry deliverables would improve the energy performance of any building, by integrating and using information effectively during the design process.
The objective is to create the building loads from the architectural design model and then use this information to design and right-size the HVAC systems. With a clear and robust framework for measuring and verifying energy performance indicators, the design team can make informed decision based on actionable metrics. This process is designed to promote iterative energy simulations in order to achieve certain energy performance targets, such as net zero and beyond.
In order to make this process work, it first starts with the integration of BIM for energy modeling applications. This is accomplished by exporting a good quality gbXML or IFC export file from a BIM project. These files can be imported into most energy modeling applications, which then creates a digital link between BIM and energy modeling. As the federated BIM project evolves in complexity and level of detail throughout the design process, the energy modeling integration link is lost, but the information parameters remain. If the geometry or spaces change after the integration, the modifications can be copied back using the 5 fundamental modeling techniques into the integration model and then re-integrated in order to maintain the BIM link between applications.
Interoperate Between BIM and Energy Modeling
We can use these information parameters to exchange data between the two applications. That could be a third party defining space and component properties in Revit and sending that information down to the energy modeler. Or it could be the energy modeler producing building loads or systems data to be inserted within the relevant space and component parameters. This way the building’s information resides inside the BIM and the simulated data is accurately representing the architectural and mechanical/electrical design.
The process of exchanging information bi-directionally between BIM and third party application is where the UK is heading with their BIM mandate for 2016. They define level 2 BIM as “a single environment to store shared asset data and information; accessible to all individuals who are required to produce, use and maintain it.” In essence, we’re opening up a portal to move information between energy modeling and BIM applications. If you’ve maintained the integration model throughout the process, then exchanging information after an energy simulation is as simple as copy/pasting data in Excel, and in a few minutes your BIM project is filled with important and relevant data.
The bi-directional data loop works today, but we are currently working on a robust and comprehensive process to share with you (sometime early 2016). Right now you can get started by learning the first step of integrating BIM with our online training course. Share with me your feedback or comments, I’d love to hear what you think.