Human-centred Design: Simplifying features in building automation

by Katie Daniel | April 14, 2015 11:34 am

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By Kevin Callahan
At the most basic level, a building automation system (BAS) helps reduce operating costs and equipment replacement capital costs by only running systems when they are needed. For example, facility professionals could use a BAS to raise air-conditioner set-points or turn off the system in college dorm rooms in Toronto in the spring and summer, or lower heating set points in Edmonton commercial office buildings on winter weekends. The dual result is lowering utility bills year-after-year, and longer life for the HVAC equipment due to fewer annual operating hours and less frequent on/off cycling.

A properly equipped BAS can also help manage building ventilation costs. Installing wall units with carbon dioxide (CO₂) sensors enables the system to determine when fresh air is needed for occupant comfort and health, rather than continually bringing in outside air. As heating or conditioning outside air is a large part of HVAC costs, this is a growing focus for many facility managers. The types of buildings in which this particularly makes sense, are those with highly varying occupancy over time, such as schools, office buildings, and government facilities.

Benefits with BAS
In addition to saving HVAC energy costs, a BAS can reduce lighting costs, which are typically the second-largest energy demand in many commercial and institutional buildings. Facility professionals are also increasingly using BAS to manage plug loads, such as those in which office employees leave on task lights or computer monitors at the end of their work day.

Although building owners typically think of BAS only for cost savings, the systems also offer revenue generating opportunities. For example, facility managers can use data provided by a BAS to document building operating costs outside tenant leased spaces, and recapture those costs from tenants. So, in an office building, the owner could bill tenants for operating costs (such as heating and lighting) related to hallways or other common-use areas. Or, a school that rents its gymnasium for community recreational programs could recapture costs from those users for ancillary space use such as corridors and foyers.

By enabling better monitoring and control of building systems, a BAS can reduce utility costs by about 15 per cent. The savings for most buildings range from $2.48 to $4.96/m², according to the Metropolitan Energy Policy Commission, which is located in the cold-climate Minneapolis/St. Paul region.

Achieving such cost savings requires facility professionals to be able to readily retrieve and make use of performance data the BAS generates. Such building analytics are the heart of a ‘smart’ building, and are what makes a BAS more than a glorified, programmable thermostat that turns off the HVAC equipment and other building systems according to a fixed schedule.

Building analytics provide facility managers the information needed to optimize building performance. This could include actions as seemingly simple as ensuring they are not simultaneously heating and cooling the same building area or that lights are turned off or dimmed when the building is vacant. A BAS can also help with specialized facility needs, such as an airport that needs to determine how many escalators really need to be kept on in the early morning when only a few passengers are in the terminal, or a hospital that wants to figure out the best timing for posturing its surgical suites.

Making the system as efficient as the building
Although a BAS can save a facility’s owner thousands in annual energy costs, many users do not achieve the full benefits. The problem is a number of systems are not intuitive to use, so their capabilities go untapped. Earlier iterations of some assemblies seemed to highlight a design conceit in which people should adapt to the machine, and if not, too bad for them.

BAS manufacturers are now taking a different view of their systems; they are understanding the machines need to be adapted to people. As a result, some automation systems incorporate human-centred designs to make software, wall units, and control modules simpler to use, while still providing powerful functionality. The intent of this design philosophy, which centres on ‘usability testing,’ is to “empirically evaluate the usefulness, effectiveness, and acceptance of a product at various stages of the design process,” according to Carolyn MacGregor, an associate professor at the University of Waterloo.

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Identifying a human-centred BAS
Specifying a BAS that is simple to use requires attention to the human-centred design features in the system’s software, control module, and wall units.

Software
Anyone who has learned a new software program knows it is often a trial-and-error process, with frequent reference to online manuals and calls to tech support to figure out “where is the X?”, “how do I do Y?” and “what is a Z?” Too often, programmers design software to make it easier for the computer to run it, than for the user to make sense of it.

While it is somewhat easier for someone who knows a word processing program, for example, to learn another word processor, many building professionals will not have encountered BAS software before. This makes it especially important the program be intuitive. A well-designed program can enable a new user to open up the BAS software for the first time and immediately see and understand the status of various building systems, and make adjustments to them. In addition to enabling the user to more fully operate the BAS, a simple-to-use program saves training time and costs.

One of the most important advances in BAS software design has been the introduction of graphical interfaces, rather than text entry and output systems. Many BAS now use schematic images to show building equipment, its operating status (e.g. heating or cooling) and what the environmental conditions are in various building spaces—such as temperature, relative humidity (RH), and CO₂ concentration. As with other types of software, however, the program might not incorporate human-centred design elements.

Some building control manufacturers maintain user-testability labs to evaluate their BAS software in detail. Software usability testing is an iterative process informing all stages of the design process, and is not just having people try out a near-final beta program and asking them about what they think. Instead, it involves careful observation and measurement of the person’s performance, and noting where they have difficulties, from the earliest stages of software design. At each stage, the programmer makes adjustments and then retests the software until the program is intuitive. Design revisions might include:

• refinements to icon style, size, and placement;
• restructuring the menu tree;
• changing colour coding;
• redrawing equipment schematics; and
• similar enhancements.

In addition to changes resulting from usability testing, another simplifying feature introduced in leading BAS software in 2014 is the use of HTML5. This latest web-creation language empowers facility managers to remotely access the BAS from any Internet-connected device—including tablets, smartphones, and desktop computers—without the time and hassle of installing third-party software plug-ins.

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Control module
An essential simplifying feature of any BAS is a control module that incorporates the BACnet protocol. Developed by the American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE), BACnet is a data communication protocol for building automation and control networks. It has become the industry’s open standard for BAS and numerous building systems.

“Capabilities vital to [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 the Institute of Electrical and Electronics Engineers (IEEE).

Today, BACnet-enabled BAS can monitor and control building systems ranging from HVAC to lighting, electrical outlets, access control, life safety, vertical circulation, and many others. This interoperability greatly simplifies work for facility managers, as they can manage nearly all building systems from one integrated platform. For example, they can schedule a building’s HVAC equipment and lighting using one tool, rather than having to synchronize schedules across different control systems.

To further enhance interoperability, advanced BAS control modules incorporate multiple communications protocols such as BACnet, Tridium’s Niagara Framework, or LonTalk.

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Wall units
For facilities in which the occupants are given some control over their interior environment, such as commercial offices, the wall units’ ease of use is important. To many, the environmental controls can seem obscure. Beyond providing building occupants a better experience, installing intuitive controls saves the facility’s staff from having to answer calls from disgruntled people asking, “How do I turn the heat up (or down)?”

Similar to BAS software, some manufacturers undertake extensive usability testing for their wall units. In one system, this has led to a wall unit design with the simplicity and sophistication of a smartphone. To achieve this, the unit’s developers prepared and refined sketches of how the user interface might look and operate, then created an interactive prototype running on a tablet device. From this mockup, they closely monitored approximately 25 to 30 people with varying levels of building control experience using the system. The next stage of human-centred design involved installing beta test units in multiple real-world settings and recording how people interacted with the unit. For this particular product, refinements included:

• icon size and placement to more closely resemble a smartphone;
• reversal of temperature controls to simplify use for both right- and left-handed users;
• addition of navigation icons to help enhance user understanding; and
• zone of interaction tightening to eliminate dead zones on the unit’s touch screen.

These and other changes indicate the level of attention necessary to achieve a truly human-centred design.

Of interest to facility professionals, some wall units also offer advanced settings that include service tech for building commissioning, and system overrides. Such codes empower field technicians to work on the sensor right in the room without special equipment or access, which can help streamline initial building commissioning, along with service calls in the years to come.

Conclusion
In addition to the thousands of dollars per year a BAS can save a building owner, the systems have the added financial advantage of a short payback period. According to some estimates, building control retrofits and control strategies have a payback period of only three to four years.

When specifying a BAS, in addition to the system’s technical capabilities, considering one designed according to human-centred principles is crucial. This can help ensure the system is used. While a BAS manufacturer or delivery agent can explain what usability testing went into their system, the most effective way to know is to test the system’s ease-of-use for yourself.

[5]Kevin Callahan is a product owner and evangelist for Alerton, a Honeywell business. He has 38 years of experience in the building control technologies field, including control systems design and commissioning, facilities management and user training. Callahan can be contacted at kevin.callahan@honeywell.com.

Source URL: https://www.constructioncanada.net/human-centred-design-simplifying-features-in-building-automation/

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