Accurate energy analyses and area calculations through 3D models

Norm creates a 3D model for existing properties and new buildings that is optimized for energy analyses. The model is created in accordance with all current standards (SIA 380/1:2016, 380:2022, SIA 416:2003). The data can be efficiently imported into energy simulation software, such as the GEAK tool, via an interface.

The thermal building envelope according to SIA 380:2022 refers to all components that separate the heated interior of a building from the outside air, the ground, or unheated rooms.

The components that belong to the thermal building envelope include:

1. Exterior walls
2. Windows and doors
3. Roofs and ceilings against outside air
4. Floors against the ground or unheated rooms
5. Interior walls that separate heated rooms from unheated rooms
6. Components that serve to thermally separate buildings or parts of buildings

In individual cases (e.g., apartment buildings), virtual components against non-actively heated rooms are added in accordance with SIA Standard 380/1:2016.

The energy reference area (EBF) is the sum of all above-ground and underground floor areas that require heating or air conditioning (conditioning). Floor areas with a clear room height of less than 1.0 m are not included in the energy reference area. The energy reference area is measured gross, i.e. including external dimensions. It is defined by the SIA standard SIA 380:2022.

Linear thermal bridges are points in a building where components such as walls and ceilings meet and their connection causes increased heat conduction, leading to heat loss. We identify the following three types of linear thermal bridges: window stops, balconies, and building bases.

The abbreviations are derived from English. Slab for ceilings and floors. Wall for walls, Roof for roofs, Window for windows, and Doors for doors. The abbreviations consist of 5 characters, e.g. Wa001, Wa002, etc. In the case of thermal bridges, the designation is derived from “window stop” for window stops, ‘balcony’ for balcony connections, and “perimeter” for the building base. Virtual elements are specifically designated as such by the letter V (e.g. VSl01).

The facade areas are net areas. This means that the windows do not need to be deducted.

Optionally, the shading factors can also be supplied in GEAK XML. These are calculated on the basis of the shading on the building and the surrounding area using algorithms developed in accordance with the SIA 3801/1:2016 standard.

The 3D model can be ordered as an option in open source IFC4. This format can be read by all common architecture programs.

We generate an XML file that can be imported into the GEAK tool (https://www.geak-tool.ch) using the “Import XML in actual state” option. We provide two variants. A detailed variant that contains all elements as in the original 3D model and a summarized variant that summarizes elements according to orientation. In the summarized variant, the abbreviation is preceded by a Z and the numbering is renumbered (e.g., ZWa01).

The planning documents include the following PDF documents:

• Presentation of the thermal envelope as a floor plan and side views, including references to the components.
• Presentation of the energy reference area, including dimensions.
• Documents showing the windows and thermal bridges.
• In addition to the planning documents, all areas and dimensions, including references to the IDs, are provided in tabular form (PDF and Excel).

As an option, a gbXML (https://www.gbxml.org/) model can be created. gbXML is a 3D format that can be used by many simulation software programs (e.g., energyPlus). It is not possible to directly reference the components in the plan documents and the gbXML file.

GEAK XML and gbXML can also be imported into Lesosai. We are working on integration with Enerweb via XML. If you are interested in this, please feel free to contact us.