AutomatedBuildings.com Article - Continuous Optimization – Getting the Most out of Your Building Automation System

Let’s say you have a well managed, well maintained, relatively efficient building. Someone offers you the chance to reduce your energy use by at least 10%, improve tenant comfort, and install new controls features - all with a payback of 2 to 3 years. Intrigued? Skeptical? These are the results for more than 50 of SES Consulting’s Continuous Optimization clients this year.

Anyone with experience in building automation knows that, from time to time, your system needs a tune up. Building performance declines over time and, as a consequence, energy use increases. Poor performance can be the result of deficiencies in the original commissioning, broken or miscalibrated sensors, conflicting set points, or manually overridden equipment to name a few common problems.

The standard response to these issues is to embark on a retro-commissioning (RCx) of building systems; identifying and fixing all the issues that have arisen over time. Although RCx can be very effective at reducing energy consumption in a building, the persistence of savings can be poor. In a few years you’re likely to find many of the same problems and poor performance that existed before. Breaking out of this cycle is the motivation for Continuous Optimization.

Continuous Optimization addresses the shortfalls in the RCx process by incorporating real time feedback on building performance that alerts staff when building performance starts to slip. Enabling your operations team to identify and correct the problem when it occurs and maintain optimal building operation. The following table shows the results of two recent Continuous Optimization projects in British Columbia.

Although the savings and payback are impressive, more important is the fact that more than a year later these savings are being maintained and even improved on, using a Continuous Optimization approach.

Beyond the energy savings from returning systems to their original operating condition, there are often extensive opportunities to improve operations efficiency when compared with the original design. Installing new controls technologies or using strategies that weren’t available or cost effective at the time of the original build, can lead to even greater savings. The rapid development of new controls technology combined with falling prices for many of these items has made these controls accessible for a relatively small investment. The table below shows a sampling of some common measures that can be implemented as part of a Continuous Optimization process.

The common purpose of these measures is to allow the building to respond better to variable loads. The environment in which a building operates is always changing; people come and go, weather changes and daylight levels go up and down. Older buildings tend to maintain their systems operating at constant loads usually designed for maximum occupancy, unable to take advantage of the changing loads to make the building more responsive, comfortable, and save energy. With the addition of new control strategies and devices such as variable speed drives and sensors to measure air quality or detect occupancy, we can use the existing BAS infrastructure to respond and meet changing conditions, significantly reducing the energy footprint of the building.

Continuous Optimization starts with collecting real time data on the building operations. This information can be collected using the building’s BAS or by software monitoring real time energy consumption. This software, often cloud based, is known as an Energy Management Information System or EMIS. The real-time data is used to better understand the operation of the building so that a performance baseline can be established. The baseline is then used to verify the energy savings once the building has been optimized.

During investigation, the energy conservation opportunities and operational deficiencies are identified from a combination of on-site investigation and review of the BAS and EMIS. Real-time energy data can reveal important information about the building that is not obvious from monthly energy bills. As an example, high overnight base loads or unusual demand spikes, readily visible in real-time data, may indicate load scheduling and demand shifting opportunities. Once the opportunities are identified, a list of potential measures is developed, and the most cost effective or desirable of these are then selected for implementation. The measures are implemented by a team including the consultant, contractors, and building operations staff. During implementation the EMIS provides valuable feedback on the effectiveness of each measure, allowing your team to make adjustments and ensure the maximum energy savings potential is achieved.

Maintaining those hard earned energy savings is the heart of what differentiates Continuous Optimization from a standard RCx approach. This is often the component that presents the greatest challenge for many facilities. One or two set point changes that go unnoticed can dramatically erode energy savings. Training your operations staff to understand the measures implemented, identify when they have varied from optimal, and respond to these exceptions in real-time is critical. In the past, most building operations staffs have been focused on keeping people comfortable. With a Continuous Optimization program, they are also the ones with the best opportunity to maintain energy savings. We’ve found the following tools and supports are crucial for success in this undertaking:

[an error occurred while processing this directive] Saving energy doesn’t have to end at the mechanical room. Many of the Continuous Optimization tools can also allow you to communicate this success to the building occupants and administration. Energy display dashboards in public areas or allowing web access to a virtual dashboard can be a great way to gain the support of building occupants. Real-time feedback on staff-led initiatives such as turning down the temperature or turning off lights has proven to be an asset in motivating occupants. People are much more willing to go the extra mile when they know that their actions are making a difference.

The measures and projects described above can largely be accomplished using 15 year old BAS technology. However, BAS are currently undergoing a rapid evolution incorporating more modern technology and harnessing the power of the web and cloud. The BAS is no longer just a tool to operate mechanical equipment, but a system that gathers information from numerous sources (temperature, weather, air quality, energy use, occupancy sensors, light levels, etc) and uses this information to operate the building in the most efficient manner possible. With more advanced capabilities, BAS technology is becoming increasingly integrated, sharing data between formerly disparate systems such as HVAC, security and lighting. This allows the system to make better decisions, avoid duplication of equipment and automate more of a building's operations. Most if not all of these advanced features can be justified in the name of energy efficiency, improved comfort, or better maintenance.

Modern BAS systems are creating new information streams like analytics or fault detection and diagnostics (FDD). Analytics expands on the EMIS described earlier; using information mined from the BAS to automatically alert staff to abnormal or unusual equipment behavior caused by broken valves, sensors out of calibration, failed controllers, etc, before they cause problems. This can greatly speed up the process of identifying and diagnosing operational problems, improving maintenance of various building systems, and preventing catastrophic failures.

The web based nature of the modern BAS also makes it easy to broadcast building related information to occupants. Below is an example of a dashboard display that combines live energy consumption data with data feeds from elsewhere on the web, in this case showing sports and weather information to draw more traffic.

Intelligent buildings allow us to go further than ever before in achieving improved efficiency and performance in a practical and cost effective manner. Below are just some of the advanced energy savings features being implemented in several SES Consulting projects.

Advanced Control System Enhancements

An advanced, integrated, BAS allows you to turn off ALL lights and non-critical plug loads in a building when the security system or space occupancy sensors indicate the building is empty. Intelligent occupancy sensors and advanced algorithms can not only tell you if someone is present, but how many people, and automatically adjust the lighting and HVAC system appropriately. SES has used this strategy with great success in intermittently used spaces such as university lecture theaters to avoid bringing on all of the lights and HVAC systems if the space is only being used by one student. These represent a small sampling of the opportunities to customize advanced control systems to meet the unique needs of your facility.

Taken together, these features make it possible to operate buildings smarter and more efficiently, making a powerful business case to upgrade to a modern, state of the art, control system. More importantly, the web enabled interfaces and cloud based services facilitate the sharing of key performance information throughout your organization, from occupants, to operations, to executives at the enterprise level.

The opportunities to automate and improve building operations will continue to grow and evolve. Continuous optimization, whether you have a 15 year-old BAS or a fully integrated modern system, will allow you to take full advantage of these systems, achieving and maintaining optimal building operations throughout the life of your building.

Brad White, P.Eng, MASc, Principal - Brad has four years of experience working with energy systems as a researcher and mechanical engineer. His work has focused on seeking ways to improve the sustainable use of energy through conservation and improved efficiency. Prior to joining SES Consulting Inc., Brad helped develop new manufacturing techniques for clean energy technologies as a master’s student and research engineer at UBC.

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