In October I delivered a brief presentation at the United Nations Environment Programme (UNEP) Sustainable Buildings and Climate Initiative (SBCI) Fall Symposium in Philadelphia, PA. The topic of my presentation was Commissioning Sustainable Buildings and the following contains the content of that presentation.
First things first, what is the magnitude of the opportunity relating to commissioning the existing building stock around the world as well as the new buildings that are coming online every day? According to the Commercial Building Energy Consumption Survey, there were nearly 4.9 million commercial buildings and 71.6 billion square feet of commercial floor space in the United States in 2003. As reported by Pike Research, commercial buildings worldwide could encompass as much as 380 billion square feet. And since buildings represent 40 percent of the world’s energy consumption and related one-third of greenhouse gas emissions, the Intergovernmental Panel on Climate Change indicates that our existing building stock is the number one opportunity in mitigating or reversing climate change.
So what exactly is commissioning? According to the American Society of Heating Refrigeration and Air Conditioning Engineers (ASHRAE), “The commissioning process is a quality oriented process for achieving, verifying and documenting that the performance of facilities systems and assemblies meet defined objectives and criteria.” More simply stated, commissioning verifies that the intent of the owner is reflected in the design documents — that systems are installed per design and that they operate as they should. You may be asking, “Doesn’t my design team already do that?” Unfortunately, the answer is no. Not to say that this is the fault of the design team but rather the fault of an antiquated process of design and construction in the face of shrinking budgets and timelines while technological complexity continues to rise. Additionally, a siloed design approach that lacks collaboration across disciplines continues to make delivering a properly operating facility a difficult task. Because of these and other reasons, commissioning has filled a wide gap and continues to contribute to the delivery of high-performance buildings that operate as intended when initially occupied.
I purposely used the phrase “when initially occupied” because despite all that is done in design (commissioning, the pursuit of LEED certification, the use of an energy model, inclusion of high-efficiency HVAC components), design and construction only sets the stage for performance and cannot be relied upon to maintain high performance on its own throughout the useful life of any facility. New construction commissioning is a one-time event and does not do much in the face of performance decay which can sap the energy performance of any building by as much as 30 percent in the first few years (ASHRAE). We must remain diligent throughout the entire operations phase of a building to maintain the potential of energy related performance owners have come to expect.
There is much to consider when looking to reduce energy consumption, the related costs and GHG emissions:
- Renewable energy installation
- Infrared imaging
- Envelope commissioning
- General retrofits
- Energy service company (ESCo)
- Common Carbon Metric
- Energy modeling
I’m not saying not to do any of these but to consider some prioritization. Proceeding with some of the above strategies is like having dessert before your dinner. Where to begin then? Start with existing building commissioning to a) help prioritize these opportunities and b) first make what is in place operate the way it should. This way, your building may capture savings that can help pay for things like a retrofit or a system upgrade. In fact, a comprehensive existing building program may enhance the outcomes of any of the above options.
An existing building commissioning program starts with an energy audit or facility analysis but many stop there and still expect savings. An audit is just a report that generates a list of deficiencies and opportunities to optimize a building’s energy consuming systems; it lacks actual implementation of those items. Without implementation, operational savings will not be realized.
So while new construction commissioning, benchmarking and energy audits are absolutely essential, they barely get us out of the garage and on the road toward true optimization of operational performance. We must dive much deeper in this area to realize a high-performance (or any) building’s potential.
If I want to stress anything in this article it’s the need for persistence in any building, above and beyond typical preventive maintenance programs and design and construction best practices. Like your car, a building’s systems degrade over time. Components break or wear out; sequences of operation are “temporarily” changed and never restored; sensors lack regular calibration or do not work at all — all of which cost you far more than you might realize. Add this consistent decay to stretched budgets, understaffed teams and only having so many hours in the week, it’s no mystery why there is so much opportunity for ongoing persistence in a comprehensive existing building commissioning program. And the proof is in the following case studies (among many):
LawrenceBerkeley National Laboratory
“Energy savings from a utility-sponsored retro-commissioning (building tune-up) program targeted to large commercial buildings ranged from 3 percent to 19 percent, but those savings may not persist beyond a few years ... The reasons for savings degradation include … sensor and device failures, and operator turn-over.”
CaliforniaCommissioning Collaborative
“New construction Cx will result in a range of energy savings between $0.02 to $0.19 and non energy savings between $0.23 to $6.96 per square foot — a total opportunity of $0.25 to $7.15 per square foot.”
Energy Systems Laboratory (Texas A&M University)
“In Continuous Commissioning projects undertaken in various building types across the U.S., the average annual energy bill savings opportunity is 22 percent (ranged from 8 percent to 45 percent).”
The evidence is clear that we should be doing far more than what is typical in the design construction and operations of our buildings. And even if you are applying the currently established best practices of new construction commissioning, energy modeling and LEED certification, you must continue to strive to bridge the gap between the design and construction process and operations. There is no “set it and forget it” button on buildings. A program of persistent and ongoing commissioning is the only way to address the inherent performance decay in a building and properly prioritize other operational and energy related enhancement programs. If we can take this one additional step in the typical standard of care applied to operational programs, a tremendous amount of energy, GHGs and money can be saved.
The slides accompanying this narrative can be found here: http://prezi.com/gpej6dflar_j/111020-unep-sbci-commissioning-sustainable-buildings-jdq-2/or here: http://www.unep.org/sbci/pdfs/Oct_symposium/Commissioning_Sustainable_Buildings_JQ.pdf.