Since the development of the mechanical bi-metallic strip thermostat in the late-1800s by Warren Johnson (who founded the company that would eventually become Johnson Controls), we’ve sought ways to optimize our indoor comfort. While simple temperature regulation was certainly a wonder when it was invented, today’s smart building technology can control not just temperature, but also interface with lighting, indoor air quality devices , security systems, and more.
On a residential level, controllers such as Google Home or Home Assistant may be appropriate. On a larger scale, however, smart building control solutions have been in the works since before Google–or even the internet as we know it today–existed. These sophisticated controls can be used to keep indoor occupants comfortable, safe, and healthy, and can do so while saving energy and maintenance costs.
Three Levels of Smart Building Control
Smart building equipment controls are generally divided out into three distinct layers:
• Unit Controller: The onboard or adjacent hardware and firmware package that controls a single machine directly. This device (for example, an HVAC controller) may communicate with supervisory hardware for higher level instructions and coordination with other machinery.
• Supervisory Controller: These control a hardware and firmware package for an overall entity–generally a single building. These units resemble an industrial PLC and communicate with different unit controllers. They’re able to coordinate between hardware such as HVAC systems and VAV (variable air volume) units, and even lighting, safety, and security systems. Such smart building systems can monitor for equipment faults and predictive maintenance concerns and can allow technicians to log in remotely to help diagnose and rectify faults.
• Enterprise-level Controls: Beyond a single building, a series of supervisory controllers–which may be spread out over an industrial campus, a college, or even a wide-ranging geographic area–can communicate via enterprise-level controls. Unlike unit and supervisory hardware, enterprise-level controls generally don’t take the form of a dedicated physical controller, but instead function as a cloud-based web app. This gives enterprise-level personnel an overall picture of how buildings operate at a high level, while allowing them to drill down much further.
Energy Efficiency Benefits and Future Improvements While supervisory and enterprise-level controls sound impressive, they can also facilitate real-world cost and energy savings. If a supervisory controller operates over not just the HVAC system, but also lighting, occupancy sensors, and indoor air quality sensors, an overall picture of the building can be put together and acted upon. For instance, if people occupy certain offices, but not others, a supervisory controller could close off HVAC airflow to unoccupied rooms, while also turning off the lights to further decrease power usage. In response to the closed off rooms, the HVAC fan could then decrease its speed to match lowered overall airflow needs. The amount of outside air being brought in could also be tuned to maintain the appropriate level based on the number of people inside. On an enterprise level, remote monitoring of equipment allows for immediate reactions to problems, without always needing personnel on-site. Enterprise level monitoring is also ideal for longer-term planning, allowing building owners to see how investments in efficiency and/or predictive maintenance work out over time.
Predictive and Remote Maintenance for Smart Buildings
At the end of the day, if a machine is sub-optimally maintained, this can have a very detrimental effect on efficiency. A supervisory or even enterprise-level control setup allows technicians to monitor environmental levels versus inputs to the system to determine if there’s degradation in performance over time. This would potentially indicate the need for a refit. Data from dedicated predictive maintenance sensors –such as an accelerometer used to sense machine vibration–could be used with the help of an AI-based model to help determine if maintenance is needed before breakdowns occur.
Once intervention is determined necessary, whether through predictive methods or due to maintenance “scheduling itself” via breakdowns, off-site technicians can then log in remotely to find the specific problem. For instance, if an air duct’s pressure is lacking, even though the fan speed is turned up to the maximum, a technician–often contracted via a long-term maintenance agreement through an equipment vendor–might recommend that a belt be replaced due to potential slipping. A general in-house maintenance technician can then “turn the wrench,” saving a visit from an expensive specialist.
Open Standards Pave the Way for Interoperability
Manufacturers like Trane, Johnson Controls, Automated Logic, and Siemens have their own proprietary programming systems on the unit controller level, as well as supervisory and enterprise-level options. If one hardware manufacturer meets your needs, and you’re happy with pricing (and trust you will be in the future), such a system could work very well, and potentially save installation and maintenance headaches.
At the same, technology rarely stays the same, and a company that meets your needs currently may not be the most optimum solution for the future. The good news is that most modern systems can work together under a protocol called BACnet, or the Building Automation Control network. The BACnet protocol provides a standard way of representing device functions, if they are defined on a particular machine.
The BACnet protocol was first proposed in 1987 and published in 1995, giving it well over 25 years to propagate throughout the industry. It’s an ANSI/ASHRAE standard and is also published under ISO. Equipment vendors are often happy to recommend the use of this interoperable standard, and since BACnet is an open standard, control systems can be specifically built around it. Tridium, for instance, produces controllers and software that can interface a wide variety of unit controllers via BACnet.
Smart Building Systems: An Open and Efficient Future
Whether you’re a single building owner, supervise a range of buildings, or rent space from a landlord, the future appears to be more efficient, comfortable, and (unplanned) maintenance-free than ever before. Open standards will potentially lead to even more advancements and competition among vendors, and ultimately better comfort and lower costs for end users (those of us that spend most of our time indoors).
Thanks to Brian Stortz, AEE Certified Energy Manager, for his input on this article.
