The goal of these innovative systems is to save energy and to provide equal or better indoor environmental quality. Too often, however, theoretical gains are not realized in the final product. The reasons span from design and specification through manufacturing, installation, operation, and maintenance. The practice of commissioning is poised to address all of these aspects, however, it needs to be focused more intently when innovative systems are involved.
Market forces with a relatively minor regulatory element largely drive the evolution of standard building equipment and systems. In order to compete, manufacturers and engineers have had to provide reliable products with the lowest possible first cost and low operating cost.
In the current market environment, an innovation must surpass a high barrier to displace a time-tested approach and become incorporated as a standard procedure. Before this happens, the equipment or systems in question must go through a transformation period where those who adopt the innovation incur the associated heightened costs and risks.
When a force that is essentially non-market, such as LEED, drives or accelerates the application of innovations, the barrier is lowered and there is a tendency for those innovations to pervade the market at an earlier stage of development. This is likely to extend the transformation period where adopters incur some of the burdens associated with un-tried or less-tried approaches.
Some examples of equipment and systems considered to be innovative to varying degrees include: heat recovery systems; evaporative cooling; stack-effect cooling; ground-source heat pumps; thermal energy storage; under floor air distribution; low temperature air distribution; and local renewable energy e.g., photovoltaic, solar thermal, and wind energy.
It is important that the intensity of the commissioning effort be closely tailored to the nature of the systems and equipment being commissioned. Innovative equipment and systems require an intense level of commissioning because they are relatively unfamiliar due to the fact that they are not produced or used in the quantity that standard systems are, and usually evolve faster.
Commissioning of buildings as a specialty, distinct from the designer's role, is relatively new. There is a growing consensus that the industry needs it - but many who believe also find it hard to define exactly what it is.
Coupled with the proprietary nature of the control marketplace and the rapidly evolving nature of computers, it is almost impossible for an HVAC design engineer to maintain a detailed understanding of the different manufacturers' DDC offerings.
This makes specifying controls for competitive bidding much more difficult than it was when control systems were built of standard off-the-shelf pneumatic components. The solution many designers have arrived at is to specify the control system in terms of written descriptions of performance, and leave the actual application engineering of the system to the vendors, resulting in a design-build scenario for the control system.
Compounding the challenge of assuring the quality level of complex building systems, the current culture seems to drive professionals to become more and more specialized. Hence, the mechanical engineer who in the past might see his design through as it is implemented now finds that productivity demands he stay at his desk and produce more designs instead. The result is that nobody with detailed design understanding is in a position to verify the proper implementation of the design. Both of these trends mean more potential problems for building owners. Commissioning providers are working to identify and correct any such problems as early as possible and boost the quality level of the completed building project.
The excitement generated by an innovative approach can also lead to losing track of the building's operational requirements or design intent. What sounds like a good idea at first may not stand up to careful analysis. The anticipated savings may never materialize, and the risk of increasing operating cost due to malfunction or operator error is introduced.
When an innovative system or piece of equipment is specified, it will clearly not be the same one that worked well on the last 100 projects. Its application criteria will need to be mastered and its interaction with other systems analyzed carefully. It will not have the track record that standard systems have, making the available reference literature less supportive and performance assumptions may need to be reevaluated.
The individuals installing, starting, and testing new building systems and equipment have gained most of their training and experience with standard types and are less likely to be prepared for varying procedures.
The commissioning provider's emphasis on functionality can make him an invaluable asset to the design team in maintaining and raising the level of quality of the design. The roles of owner's advocate and keeper of the design intent can provide perspective to help the application of innovations stay down to earth and connected with reality by reviewing documents with a skeptical eye and a system-wide perspective. Special attention should be given to all innovative systems and equipment to ensure they are selected and applied properly and with care.
The accelerated adoption of innovative systems is critical to achieving the goals of the green building movement. By tailoring commissioning appropriately to the requirements of innovative systems, the risk to green building may be mitigated and overcome.
Adam Wheeler is the president of Sherrill Engineering Inc., San Francisco. He can be reached at 650-952-6466.
Publication date: 07/10/2006