The background to this thesis is that BIM-based energy analysis could make the evaluation of different design options more efficient and give project owners, architects and other designers better possibilities to support decision making in early stages of the design process.
In the first part of the report the basics of BIM is described, differences between traditional and BIM-based energy analysis, the structure of the two most common file formats, gbxml and IFC, how energy efficient design work could be performed and different ways of performing parametric studies with sensitivity analysis and optimization.
The second part of the report consist of a study of a residential building where modeling was done in Revit Architecture 2010. A connection was created between the BIM-model in Revit and the energy analysis tool IES, Integrated Environmental Solutions <Virtual Environment> 6.1 by exporting the BIM-model to the file format gbxml and then import it to IES.
A simple study has been done on two different roof shape options and two different window types where the differences in specific energy usage and maximum temperatures summer time has been generated. The study was performed with the aim to investigate and describe a BIM-based way of working.
In the process of importing geometry directly from the BIM-model which already has been done by the architect through the gbxml-format and that all input data was added to the model in IES with the use of templates that can be saved and reused, comparative studies was made possible with a low extra work and an effective way of handling calculation data.
The study indicated that modeling rules and rule based, automatic geometry generation could demand extra understanding and control of that export behavior conform with desirable results. The interface in IES could probably gain on being even more intuitive, because that would speed up the time it takes to get started. The way of entering data and presenting results regarding specific energy usage could differ from what you could expect being used to programs adjusted for Swedish conditions, e.g. VipEnergy.
IES is advanced and includes many possibilities to advanced analysis of a building as one system. This report only describes a small part of them. It takes high competence and experience to be able to use its full capacity, which makes it important to be able to gather and engage people with the right combination of competencies.
Only geometric information was extracted from the BIM-model and remaining data was added through IES. Thus, the current connection is perhaps most suitable to be used in projects in which there are no plans of reusing the information added in IES later in the process, which the IFC-based energy analysis has a strong focus on.
Apparently, BIM-based energy analysis has the potential to become an important tool for designing more energy efficient buildings during the design process. Exploring more alternatives and investigate synergy effects seems to be of great importance. One of the industries biggest challenges is the ability to find better ways of working where information and competence can be coordinated in order to achieve better control over the design process so that meaningful decisions can be taken in early stages based on a building as a system.
Source: KTH
Author: Engman, Gustav