Smarter Buildings With BACnet, Model-Based Analytics and Service Transparency

The "New Deal" for smart buildings would facilitate a dialogue between the building systems industry and the commercial building professionals on how we collectively think about intelligent and smart systems in buildings.

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Image of two buildings wearing glasses thinking about a complicated math problem, a play on
Illustration: © IoT For All

The idea of a “New Deal” for smarter buildings is built on three critically important building blocks: the BACnet open standard, model-based analytics and service transparency.

Individually, these bring lots of value, but delivered in combination, they provide a powerful and compelling roadmap for getting the most from today’s and tomorrow’s buildings. More importantly, these attributes serve to improve the relationship between vendors and owners, as well as contributing to improving their respective businesses.

What Is the BACnet Open Standard?

Because a building is made up of many different types of equipment, functions and systems, the best solution for a particular building is likely going to be sourced from multiple vendors. A critical element of building systems is how these devices communicate with each other. The answer to this interoperability problem is an openly defined standard for a building-wide control system network, one able to offer sufficient rigidity of standards to connect everything together reliably and flexibility to customize the results required by clients.

This is where BACnet (Building Automation Control Network) comes in. An industry initiative started in 1987 and housed in the highly respected ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) organization, BACnet was the first with this vision and has continued its development work to this day. There are three key aspects of BACnet that fit the New Deal:

First, BACnet is a network protocol for devices to communicate with each other. Initially using serial communication networks like RS-485, popular in the ’80s and ’90s and still in wide use today. BACnet’s networking prowess have evolved, adopting TCP/IP as the Internet became widespread. And now, BACnet is moving to leverage Web Services, the very technology that powers much our digital world today. It’s worth noting that throughout the last three decades, cybersecurity continues to be a critical consideration in the BACnet community.

Second, BACnet provides a way for devices and supervisory equipment to interrogate the system to understand what BACnet devices are installed, and what information they have. The information contained in BACnet devices include data types expected in building systems, such as temperature, binary switch status (On/Off), fan speeds (for fans and motors) and complex data structures such as calendars, event logs, door access profiles, etc. BACnet also allows vendors of specialized products to create non-standard information profiles that allow their devices to be a responsible citizen of the BACnet network.

Last, BACnet encapsulates a great deal of metadata about the devices on the network. Metadata is critical for devices to expose their contexts to others. For example, information about external building temperature is useful in isolation, but comparing it to the temperature of the air around a heating element in a duct informs not only the temperature of the building’s internal air but also the effectiveness of the heating element. In a typical building, there can be thousands of these relationships. BACnet metadata is crucial to reducing the complexity of the inherently complex building control system.

Three decades on, BACnet is the foundation of Industrial IoT (IIoT) for buildings. BACnet is currently the best way to unify the complex engineered building system. Industry adoption of BACnet is broad and growing, from equipment manufacturers, control system vendors, contractors and system integrators. The BACnet ecosystem is reliable and a safe bet for the future of buildings.

Model-based Cloud Analytics

One of the attributes of building systems is that they are each unique, even though many of the devices that make up the system are common, standard and available off-the-shelf. Each system in a building is engineered specifically for that building, with requirements that are unique to the circumstances and needs of that building, as specified by the building owner and design team.

Implementing analytics on such a system requires a thorough understanding of this dynamic. Many traditional analytical techniques such as machine learning and statistical analysis can provide some value in analyzing buildings, but to truly extract value from these systems require a model-based approach, which is what we prescribe in the New Deal.

Model-based analytics create a cloud-based digital twin of the building. Digital twins are created automatically by looking into the information from the building using the BACnet infrastructure, data models and metadata. The digital twin replicates the structure of the system, which, when combined with the continuous data flow from the building, allows continuous modeling of the building in the cloud.

These models can quickly identify issues where the physical system is not operating correctly. As per the above simple temperature example, if we know that the gas to the heater is on and the temperature after the heater is the same as that of the air before the heater, then something must be wrong.

Not only does a model-based analytics approach identify issues, but it can also often determine the cost of problems and can automatically know when the problem is fixed following corrective action. In other words, this approach not only monitors the system, but also oversees the resolution of issues identified, and thus monitors the service performed by service providers.

Another critical value of this approach is that we can rewind the system to analyze the building as it was operating at some past date. This attribute is useful as a forensic tool, for example, to investigate why the energy cost a few months ago was abnormal. The tool can help explore what-if scenarios as part of identifying complex systemic issues.

The value of this approach for building owners and managers is significant, as it brings accountability and transparency to the task of identifying and resolving issues. Equipment vendors are held accountable for their products, and service providers are held accountable for their services. Issues that were not caused by equipment or programming failures, such as a building occupants’ behavior, floor plan changes and other external issues can be identified in a similar manner. When the appropriate changes are made, the analytics engine should automatically re-adjust the status quo to the new circumstances.

Service Transparency

We have already established that buildings are complex entities. Building owners (including managers and occupants) are the users of the building; they have their own issues to deal with and don’t have the bandwidth or expertise to manage every aspect of how their facility is serving them. At the core of what building owners must demand under the New Deal is transparency that the products and services they invest in are doing what they are intended to do.

While the key components of the New Deal are the two technology approaches previously discussed, to truly deliver the value to building owners, these technologies must be viewed as enablers for vendors to deliver their products and services with transparency.

This level of transparency was previously impossible to achieve, and many of the inefficiencies of buildings today are a result of this problem. While it’s easy to know when your HVAC equipment stops working, it’s difficult to know that a piece of equipment was performing 10% below nominal, and it’s not easy to prove that a fix was made to recover that lost 10% of performance. While 10% doesn’t sound much, multiple similar issues can compound into a material performance degradation of complex mechanical systems, costing the owner significantly, from energy usage, occupant productivity, to negative business impact.

The adherence to the BACnet open standard removes a vendor’s ability to hide behind proprietary products and removes the lock-in that vendors have traditionally used to secure additional projects and lucrative service contracts. The New Deal posits that when a quality-focused vendor offers open products and service transparency, they will receive an increased level of business and the loyalty of the owners who appreciate the transparency.

This transparency is beneficial both to the vendor and the owner. The vendors can use it to analyze initial problems and use any information gained to propose a solution. The owner can then see the rationale of the vendor’s proposal and the result of the service work. Should the problem persist, both vendor and owner can openly review the data and their decisions, and, if necessary, escalate the issue without finger-pointing.

Service transparency is not a nice-to-have business model nor a marketing slogan. One of the reasons for the success of the consumer internet is leveraging information technology to enable transparency. When you think of Yelp, Airbnb, TripAdvisor, Amazon, or other successful online services, it is transparency that contributes to the quality of products and services the customers receive. In the New Deal, providing service transparency is a core attribute of the successful relationship between vendors and owners.