How Building Automation Systems Work

Building automation systems control various components within a building’s structure, such as heating, ventilation, air conditioning and security alarms. The primary goal of this type of infrastructure is to improve system efficiency, reduce costs and increase safety. A centralized building management platform brings all of these parts together, but this description is a simplification of what’s really going on behind the scenes.

Main Components of a BAS

Building Automation Systems can be implemented either during initial construction or through a retrofitting process for an existing structure. It uses five component categories to provide a smart building environment.

  • Sensors:

These devices track temperature, humidity, the number of people in a room, the lighting level and other values. The sensors transmit this information to centralized controllers.

  • Controller:

This component acts as the “brain” of the BAS. It collects data from the sensors and then sends commands to HVAC units, lighting systems, security alarms and other connected parts.

  • Output devices:

Once the controller sends out a command, actuators and relays go into action to follow the requirements. For example, they can reduce or increase the heating in a particular part of the building, dim lights in unused offices, or turn on the air conditioning before people come to work.

  • Communication protocols:

The BAS uses a specific language that’s understood by the system’s individual components. BACnet and Modbus are the most commonly used options.

  • Terminal interface:

Users can interact with the BAS through this interface. It presents information so that users can monitor the condition of the building or choose to override settings manually.

Importance of User Interfaces

The terminal interface is an important part of an effective building automation system. Organizations need a way to access the data produced by the sensors, discover whether problems need troubleshooting, and look for areas of inefficiency they can address. A poorly designed user interface may not provide the necessary access or analysis that a business needs to understand its BAS performance levels.

Modern visual data overlays provide building managers with insights delivered in a user-friendly form. Managers can quickly react to changes because it’s easy to see what’s going on in the system on a day-to-day basis. Machine-to-machine communication guides decision-makers with objective information.

Functions of a BAS

The primary function of a BAS is to provide control over heating, cooling, ventilation, lighting and other critical building systems. However, building automation systems also monitor their individual components to alert building managers about detected problems. Depending on the issue, the system may attempt to automatically resolve a problem before getting a human involved. The system’s continually monitors and optimizes its own performance, although the building manager can make adjustments as needed.

Types of Data a BAS Collects and Its Applications

A BAS has access to a wide range of sensor data, depending on the smart systems installed in the building and the needs of the business. Temperature is one of the most common data points tracked, as this information is critical for proper climate control. The indoor air quality is monitored to ensure the correct mix of external and internal air, and this method is often used to control the humidity in the structure, as well.

Pressure and chemical sensors help the system troubleshoot problems with air quality or discover issues with mechanical aspects of the building. The security system relays data that can indicate potential intruders, such as motion in supposedly empty buildings.

Alarms can come from many parts of a building, such as power supplies, elevators or electronic doors. The data gets passed along to the UI when it meets certain requirements, such as when a data center’s power has gone out and it’s switched to an uninterruptible supply.

Main Challenges of Using a BAS

Many buildings are equipped with legacy building automation systems that provide limited information to the building manager. While low-level systems operate fine with this configuration, the business can’t get the most out of optimization efforts, since there’s no easy way to get to the data. A full upgrade can require a substantial amount of upfront investment, but many managers reduce this cost by using a retrofitted system.
Vendor lock-in is another challenge. When a single company provides the integrated system in a building, adding new features often requires sticking with the existing ecosystem. A retrofit or overlaid system can overcome this challenge. Otherwise, the proprietary upgrades may offer limited features and lack the flexibility that the manager wants from a modern BAS.

The final challenge of using a building automation system is obsolescence. A decade or two after installation, the technology in the building will likely be out of date. Building managers need a strategy in place to address this eventuality.

A BAS offers an excellent way to have centralized control over a building’s systems. Modern options provide significant insights into operations, from discovering problems well in advance to continually optimizing performance. Most processes are handled without any direct input, allowing building managers to focus on issues that require their full attention.

Want to learn more about planning for a BAS or working with a legacy system? Download our latest e-book, “How to Combat Building Automation Obsolescence.”

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