Maximizing BAS benefits
To receive the most benefits from implementing a BAS, it is important to focus on analytics and building commissioning.
Analytics for high-performance building operations
A BAS is a powerful tool for gathering data needed to make informed decisions on energy management. To maximize its cost-saving potential, one must pay attention to the data the system is generating and to use it to make strategic energy usage choices—this is the concept of building analytics. In short, a BAS is not a tool to install then simply turn the heating, cooling, and lights on and off according to a set schedule.
Analytics is about ensuring a building’s managers have enough of the right data being collected for analysis. It is important to use analytics to ensure any BAS programs created to reduce energy—or any other objective—are actually accomplishing what was intended. An appropriately equipped BAS allows the facility staff to collect and store data so there is history to compare it to.
For example, analytics can help the facility managers ensure they are not heating and cooling the same spaces at the same time, as well as confirm lights are on for a purpose, rather than solely for convenience. Analytics provide a way to determine whether energy is being wasted, and where.
A BAS delivery agent (i.e. manufacturer, dealer, or consultant) can be a valuable resource for determining what analytics are needed to meet the building owner or operator’s specific goals.
Building commissioning
A sometimes overlooked benefit of BAS is the system can be used to simplify the commissioning process, for both new construction and building retrofits. Some BAS include programs to verify HVAC and other building systems are performing according to the design intent. The wall sensors of an advanced BAS enable technicians to access the system throughout the building to conduct tests and verify environmental conditions, without carrying separate diagnostic tools—the result is faster and more accurate performance verification. Proper building commissioning is crucial to achieve efficient building operations.
“The operating costs of a commissioned building range from eight to 20 percent below that of a non-commissioned building,” reports the U.S. Environmental Protection Agency’s (EPA’s) Building Commissioning Guidelines. Additionally, it is noted commissioning costs typically range from only 0.5 to 1.5 percent of construction costs, and reduce operating costs throughout the building’s life.5
For initial commissioning, the building systems as a whole need to be commissioned at the time of construction to ensure they are operating as designed and their integration with the BAS is correct. This helps ensure the building is operated appropriately to satisfy its occupants’ needs. As a basic example, in an office building the HVAC and lighting would need to be commissioned for controlling the indoor environment while the building is in use during standard working hours, whereas in a warehouse the utility needs would be different because the building likely is not in use at all times.
An even more critical action than initial commissioning is the periodic re-commissioning of a building to ensure the systems are still serving the occupants’ requirements. Additionally, because systems can degrade over time, it is important to tune them up for optimal performance.
enables it to operate at about half the
energy use of a traditional chiller plant.
Specifying a BAS
Design professionals can select from numerous BAS. Several important features to consider when choosing the system include:
- degree of interoperability of the control module;
- software’s ease of use;
- security measures; and
- usability and design style of the wall sensors.
Control module
The control module is the central processing unit of a BAS. Until the mid-1990s, the communication protocols these units used to interface with building equipment were proprietary to each manufacturer. As a result, various components would not work together unless using a single manufacturer’s equipment.
In 1987, the American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) began to actively develop a standard protocol to enable a wide range of controls and equipment to work together (i.e. interoperable). In 1995, it published that standard—known as BACnet (data communication protocol for building automation and control networks), which has since been widely adopted by BAS and building equipment manufacturers.6
“Capabilities vital to BA [building automation] applications were built into BACnet from the beginning in order to ensure the highest possible level of interoperability in an environment possibly involving multiple vendors and multiple types of building systems,” according to a report from the Institute of Electrical and Electronics Engineers (IEEE).7
Such interoperability helps ensure a BAS can adapt to emerging technologies and evolving building occupancy needs, without having to start over.
BACnet is unparalleled in providing integration of the disparate systems within a building, including HVAC, lighting, access, irrigation, utility monitoring, and metering. For example, instead of having separate systems and building occupancy schedules for a building’s lighting and HVAC systems, BACnet allows for clean integration of both systems so the scheduling is from one source.
By analogy, a BAS using BACnet is like a symphony orchestra, wherein the control module is the conductor providing direction to the numerous different building systems (i.e. individual musicians) using a common protocol (i.e. BACnet) they all understand (i.e. movements of the baton, hand gestures, and facial expressions). Although a violin is different from a trumpet, the conductor’s common direction enables them to work together to produce beautiful music.
Some BAS control modules incorporate multiple protocols (BACnet and Tridium’s Niagara Framework) for even greater interoperability than relying on a single protocol. Other protocols, like LonTalk, are also available.
Software—ease of use
Learning a new software program often involves hours of training, and/or trial and error, both of which can mean thousands of dollars in staff time. This is especially true for specialized programs such as those included with a BAS.
However, a key differentiator among BAS software is how intuitive and simple it is to learn. Although many programs now employ a graphical interface, rather than text entry alone, ease of use varies. The most sophisticated BAS software includes simple schematics clearly identifying the equipment throughout a building, and its operating status (e.g. heating, cooling). Such programs enable even novice users to readily interpret the environmental or other monitored conditions anywhere in the building, and to adjust the appropriate building system, as needed.
Another simplifying feature introduced with BAS software this year is use of HTML5. With the latest HTML format, facility professionals can access the BAS remotely from any Internet-connected device, without the time and compatibility hassles of downloading a third-party’s software plug-in. As a result of this wide system accessibility, a technician could troubleshoot a piece of equipment from the field, or a facility manager could make necessary system adjustments when traveling away from the office.
