Energy Saving Tip #4: Consider Retro-commissioning Your Building
in Green Buildings & Green Technology, HVAC
The National Conference on Building Commissioning (NCBC) defines building commissioning as “the process of ensuring that systems are designed, installed, functionally tested, and performing in conformity with the design intent.”
Or actually that’s their definition of new building commissioning. There’s another type that’s becoming more popular with every passing day, and this other type forms the substance of today’s installment of our Energy Saving Tip series.
ENERGY SAVING TIP #4: Consider retro-commissioning your building to discover and maximize hidden opportunities for improving IAQ, comfort, energy efficiency, and cost savings.
The NCBC defines retro-commissioning (RCx) or existing building commissioning (EBCx) as the activity that “applies a systematic process for improving and optimizing a building’s operations and supporting those improvements with enhanced documentation and operator training.”
The Building Commissioning Association defines the process in a bit more detail:
Commissioning for Existing Buildings (sometimes referred to as retro-commissioning) is a systematic process for investigating, analyzing, and optimizing the performance of building systems by improving their operation and maintenance to ensure their continued performance over time. This process helps make the building systems perform interactively to meet the owner’s current facility requirements.
The state of California offers a definition via its “Green California” program that not only defines RCx but offers a direct indication of its benefits:
The commissioning process can be applied to existing buildings that have never been commissioned to restore them to optimal performance. Retro-commissioning (RCx) is a systematic, documented process that identifies low-cost operational and maintenance improvements in existing buildings and brings the buildings up to the design intentions of its current usage.
RCx typically focuses on energy-using equipment such as mechanical equipment, lighting and related controls and usually optimizes existing system performance, rather than relying on major equipment replacement, typically resulting in improved indoor air quality, comfort, controls, energy and resource efficiency.
For even more reinforcement and clarification, consider the observations about RCx from the Kentucky-based Business Lexington (“Smart strategy can yield returns on energy efficiency, April 16), which explains the important distinction between RCx and a standard energy audit:
EBCx takes a holistic perspective of the building’s systems. Rather than focus on one building system, the EBCx process improves your entire building’s operation so that you will realize reduced energy consumption plus reduced maintenance and operation costs.
Facilities of more than 20,000 square feet can implement an EBCx process to assess current energy consumption, define targeted consumption levels, and close the gap between the two. The process enables staged implementation of performance improvements as time and capital allow. Unlike energy audits, this process not only looks at energy consumption, but also considers the ongoing costs of maintenance and operations. The end result is sustainable energy and operational efficiency.
The same article also describes the three key steps that make the process work:
Assessing your current facility requirements Investigating, analyzing, and optimizing your building systems’ interactive performance Improving your operation and maintenance procedures for continued performance.The article observes that the three biggest energy consumers in any facility, and therefore the ones that need the most attention during the RCx process, are hot water systems, lighting, and — you guessed it — HVAC. “The largest savings and operational improvements are found in the HVAC and lighting systems,” Business Lexington says. “Your building envelope (which is the physical structure itself) plays a large part in energy efficiency; however, improvements are often capital-intensive with lower ROI.”
(We’ll pause to point out that we talked about the importance of the building envelope in our last energy saving tip.)
So all of the above lays at least part of the conceptual background for RCx or EBCx (whichever you prefer to call it). In terms of real practical advice and instruction, the following resources may be quite helpful:
- The U.S. Government’s Energy Star program offers a free and very detailed online Building Upgrade Manual (revised October 2007) that serves as “a strategic guide to help you plan and implement profitable energy saving building upgrades.” Chapter 5 is titled “Retrocommissioning” (pdf). It includes an introductory overview that examines both energy and non-energy benefits of the process, a guide to project planning and execution, and a guide to finding “tune up opportunities” in your building.
- The EPA offers “A Retrocommissioning Guide for Building Owners” (2007, pdf), which, at 119 pages, offers pretty much everything you could hope for and “illustrates how building owners and managers can successfully use retrocommissioning as a cost-effective method to reduce expenses and increase revenue through improved building operations.” It includes an overview of the RCx process, an explanation of the roles and responsibilities of the various members of the team, a list of “Key Strategies for Success,” and a complete guide to project planning, investigation, and implementation.
- Building Commissioning: The Key to Quality Assurance (1998, pdf) was “written to aid building owners and retrofit project managers currently participating in the Rebuild America program” (which, let it be noted, is still active as a program of the U.S. Department of Energy a decade after the document was produced). Its 77 pages include information about the benefits of RCx as well as an explicit step-by-step instructions for how to do it. It also includes case studies of successful RCx projects.
- A Practical Guide for Commissioning Existing Buildings (April 1999, pdf) was prepared by Portland Energy Conservation, Inc. and Oak Ridge National Laboratory for the U.S. Department of Energy. At 151 pages it covers all of the bases.
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