BACtwin: The User Addressing System (BAS) as a Fundamental Requirement for Digitization

In March 2020, Jürgen Hardkop became acquainted with the concept of "Digital Twin (DT) of Building Automation with BACnet" for the Austrian Armed Forces (ÖBH), and in October 2020, another DT pilot project for building automation (GA) systems at the University of Basel. Together with Eike Hinck, responsible for energy management at the Building Management of the City of Cologne and Chairman of "BACnet 2017," he developed the new BACtwin concept in the AMEV AK BACtwin from the best DT ideas of the ÖBH, the University of Basel, the AMEV, and many others, which consists of the BACtwin Library (see diagram: yellow blocks) and a BACtwin description.

The central elements of the BACtwin Library are two extended AMEV profiles (AS-C and AS-D), the new object templates, and aggregate templates, as well as the machine-readable User Addressing System BACtwin-BAS.

The object templates define more than 250 standard building automation (GA) functions, each with a corresponding BACnet object type, associated properties, and recommended standard parameters. The aggregate templates define a practical standard equipment for approximately 80 standard aggregates (such as pumps, valves, fans) with GA functions.

The goals of BACtwin are extensive standardization, digitization, and automation of building automation with BACnet. The data model is designed as a transparent, future-proof modular system based on the open-source idea. It can be universally used, for example, in office buildings, university buildings, or clinics.

For software tools (see diagram: green and blue) to support simplification, error avoidance, and quality improvement through BACtwin, the templates from the BACtwin Library must be imported into planning tools, for example. BACtwin-enabled tools for planning, engineering, operation (blue), and specialized test tools (green) are intended to support lossless data exchange and as efficient as possible IT-supported building automation applications.

The User Addressing System BACtwin-BAS is crucial for the quality (e.g., structure, logic) and scope (e.g., trades) of data communication in BACtwin projects. Since previously used BAS are not optimized for standardized data models and are not machine-readable, for example, the AMEV AK BACtwin - in continuation of VDI 3814 - has developed the powerful BACtwin-BAS and presented it for the first time at the Iconag conference.

André Höhne explained the BACtwin-BAS, which is designed to be machine-readable, user-friendly, and future-proof. With the help of the BACtwin-BAS, both humans and machines can recognize and interpret the data contents clearly. Specialized test tools can validate the standardized mass data for planning, execution, and operation 1:1. The basic elements of the BACtwin-BAS are explained below.

Die Bestandteile (BAS-Blöcke) und Anwendungsbeispiele des BAS

In the BACtwin-BAS, an abbreviation and its corresponding designation form a unique identifier. This ensures clarity. Abbreviations are typically three characters long, and numbering is two characters long. If an abbreviation has fewer than three characters, missing characters are filled in with tildes (such as T~~). An empty block is filled with hashtags (#####).

The new block "Medium, Installation Location" contains important information. The medium is represented by two letters (for example, HW = Hot Water); a third letter indicates the installation location (for example, R = Return); the three letters together form: HWR = Hot Water Return (see BACtwin example component VEH01).

In the BACtwin-BAS, a distinction is made - in the further development of VDI 3814 Part 4.1 - between aggregates and operating equipment. This allows for a structural distinction between simple sensors and multiple devices (such as room control units).

In addition, Sören Zeuner, GA Manager at TU Braunschweig and member of the AMEV AK BACtwin, reported on May 23, 2023, during the repeat of the ICONAG conference on the automated translation of existing BAS into the BACtwin-BAS. Translations can be helpful, for example, in the renovation of automation systems, migration of automation systems, adaptation of existing systems to a consistent operator concept, or the automated creation of MBE system images. Mr. Zeuner developed an Excel-based tool for translation. In a practical test in a highly technical building with 5,000 data points, approximately 80 percent of the existing BAS could be automatedly converted into the BACtwin-BAS using the tool. Conditions for this were a structured existing BAS, clean data sources (EDE files), and the manual formation of unique arguments. The remaining data points are to be manually clarified using schemas and descriptions.

Practical information on the topic of BACtwin is provided in the Zoom presentation by Edelbert Löffler, Managing Director of the GA engineering office BGA, Hünenberg, Switzerland, and member of the AMEV AK BACtwin. Mr. Löffler reported in the ICONAG webinar on May 23, 2023, on the practical experiences with the first BACtwin application in Germany in a reference project for the insurer Generali. You can find the link to download the presentation materials and the recording of the ICONAG webinar here:

Link to Recording