by Michael Arny, Maren Meyers and Mary Reames — March 2016 — There is a commercial building in Madison, WI that served as the workspace for unhappy building occupants for many years. The air quality in their office, they continually complained, was exceptionally poor. Eventually, these occupants were replaced by an engineering firm who took it upon themselves to examine the building after experiencing this poor air quality as well. They initiated a basic inspection and found that the plywood on the inside of the outdoor air intake system, placed there during construction, had never been removed! The only fresh air entering the building was the air that managed to get in accidently. Thus, with a simple inspection and a basic understanding of building HVAC systems, the air quality problem that had plagued occupants for years was identified and resolved at practically zero cost.
While somewhat comical, the anecdote above draws attention to an important truth: many building systems do not function as well as they should simply because nobody has bothered to pursue fundamental-level commissioning. As a result, occupants endure substandard interior climates, and owners and lessees pay higher operating costs. The following article examines one example from Leonardo Academy’s recent project experience and two recently-published commissioning studies that contextualizes the process of commissioning in the present, demonstrates the many ways it saves money and energy, and reveals how to make it a palatable process for any facility manager.
Leonardo Academy recently teamed with a property on Boston’s waterfront to improve the facility’s sustainability by pursuing LEED for Existing Buildings, Operations and Maintenance certification. LEED is the leading system for certifying and improving upon the sustainability achievements of new and existing buildings by awarding points in 8 categories, weighted in importance by their potential to reduce environmental harm. The project performed exceptionally well in the Water Efficiency category, proving the efficacy of its water systems’ operating procedure in areas such as indoor plumbing and fixture efficiency, water efficient landscaping, cooling tower management and non-potable water source use. While they achieved exemplary water efficiency improvements, the resulting financial savings are perhaps the most compelling outcome of this project area. By identifying and addressing the largest opportunities for improvement at the systems level, and implementing these improvements, the building will incur significant annual savings.
Mary Reames, a Leonardo Academy project manager who worked closely with the building’s staff, explains how the goals of cost efficiency and water efficiency aligned:
“[The project] already had a gray water tank that collected rain and cooling tower condensate, but it was not being used as efficiently as it could have been. The original system added city water to the gray water tank when the water level in the tank dropped below a certain point. City water was added until the gray water tank was full. This left little capacity for storing gray water, if there should be a rain event soon after the city water was added. The system was modified so that city water is added directly to the cooling tower only if the water level drops below a certain point and gray water is not available. This creates more capacity for the gray water tank to collect rain water and cooling tower condensate. Piping was also added to draw all irrigation water from the gray water tank. With these changes, the use of city water in the cooling tower is greatly reduced, and its use for irrigation is eliminated, thus driving down costs.”
By preventing the unnecessary addition of city water at times of low capacity, the project team converted the gray water tank into a sort of enormous, extra-functional rain barrel where total gray water could be captures and accurately metered, rather than mixed with water from the municipal supply. Thus, a once costly irrigation system became virtually free. Notably, the added piping from the water tank to irrigation-dependent areas of the site amounted to only about 10% of the total cost of the gray water system improvements. Although the modification to allow direct city water to cooling tower modification was significantly more expensive, the project will still experience a payback period of less than two years.
The building’s success in improving water efficiency exemplifies a mode of systems thinking that prioritizes cost efficiency and leverages environmental awareness. It demonstrates how some of the simplest solutions for reducing operating cost can be found by paying close attention to the way Earth’s natural systems, such as rainwater, interact with the needs of a building, its utilities, and its surrounding landscape. This approach to building operations can be extended far beyond water efficiency.
In a 2009 report titled “Building Commissioning: A Golden Opportunity for Reducing Energy Costs and Greenhouse Gas Emissions,” Evan Mills, Ph.D. of the Lawrence Berkeley National Laboratory provides the world’s largest compilation and meta-analysis of commissioning experience in commercial buildings. The report defines the purpose of building commissioning and enumerates the many opportunities to achieve significant financial savings while also improving energy efficiency and reducing harmful emissions. According to the report, commissioning serves “to ensure that [building systems] deliver, if not exceed, the performance and energy savings promised by their design.” Figure 1 illustrates the general steps of commissioning and retro-commissioning, which Mills defines as a “systematic, forensic approach to quality assurance.” When applied well, commissioning identifies the gap between where operations are and where they should be, and uses that space to capitalize on the largest areas of improvement for both new and existing buildings.
Figure 1. A breakdown of the steps that generally comprise each phase of the commissioning and retro-commissioning process. Source: http://cx.lbl.gov/documents/2009-assessment/lbnl-cx-cost-benefit.pdf
The study developed a range of benchmarks for characterizing project performance and cost-effectiveness. The results are compelling.
For new construction projects, the cost of commissioning was only about 0.4% of the overall cost of construction. By identifying and addressing a tremendous number of energy-related problems, buildings experienced up to 16% whole-building energy savings with a payback period between about 1 and 4 years. The more comprehensive the commissioning process, the higher the energy savings—up to five-times more than least-thorough projects. Notably, the study claims “energy savings are valued more than the cost of the commissioning process,” so, through this process, the level of commissioning, energy efficiency achieved, and money saved all directly correlate (Mills, 2009).
Still, the proof of commissioning’s efficacy in reducing operating costs and resource consumption does not overshadow the fact that it can be an intimidating process—one that requires an initial investment, a learning curve (though not as steep as one might think), and vitalized attention to detail. Those adept to the often slow-moving process of adopting new practices in the building industry published a study titled “Monitoring-Based Commissioning: Benchmarking Analysis of 24 Buildings in California” that clearly defines ways to capitalize on the findings of the first (and often only) commissioning efforts.
Figure 2. Graphic illustration of three additional opportunities to optimize energy savings on top of those achieved through standard retro-commissioning.
The study identified three additional ways (illustrated in Figure 2) that monitoring-based commissioning (MBCx) can yield higher energy savings relative to standard retro-commissioning. First, monitoring should be persistent enough to identify problem early on from metering and trending. Second, any new measures found during the initial retro-commissioning that are unlikely to be completed from the traditional test protocols in place should be conducted. Finally, one should continually identify new problems that may occur after initial inspection, such as inefficiency caused by a change in building use (Mills & Mathew, 2012). By extending the initial commissioning effort into a continuous improvement process, savings in money and energy can continue to increase rather than degrade.
Combined, the case of Leonardo Academy’s recent project and the aggregated results of the above commissioning studies demonstrate how environmental goals and financial goals are not necessarily misaligned. In fact, the process of focusing on efficiency improvements in building operations often inherently yields savings in cost. Although the initial investment of time and capital tends to dissuade many from seeing sustainability improvement in their building as a worthwhile venture, the experience of those who have and the compounding improvements enabled by monitoring based commissioning suggests that environmental sustainability should be a priority of everyone seeking to reduce operating costs.