June 2009 |
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Thomas Hartman, P.E. |
Have you ever been asked a question to which you - 1) know the answer, and - 2) at the same time know the answer is not going to please the questioner? Many of us in this industry are in that position right now when we are asked how to improve the energy performance of building systems. The one asking the question, usually a building owner or project engineer well into the design process, wants to know how they can tweak the design to achieve higher levels of efficiency and reliability they know are possible but elusive to achieve. When I hear this question I cringe a little because I know the correct answer is probably not what they want to hear – and the result may be active denial or even a rebuttal that will make any further thoughtful discussion moot.
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My experience is that owners and engineers want the
answer to be along the following line - that there is some small item, a change
or addition to the equipment specification or the commissioning process, or
improved operator training or some magic set of control sequences that will
assure ultra-efficient building energy system performance. But in reality, while
all these things can contribute to improved efficiency, simply adding any or all
of them to a conventional design process almost never does achieve the desired
improvement in performance. The right answer is that to achieve and maintain
truly high performance building operation, the process by which buildings are
designed and constructed needs to change so that someone has both the
responsibility and the authority to make certain the desired level of
system performance is achieved and maintained over time. “Authority” means the
oversight to ensure the right equipment, configuration, and controls for the
application are selected and installed. “Responsibility” means being on the hook
to ensure projected building energy system performance is attained and verified
daily, weekly, monthly and annually for years to come.
When that answer is given, the response too often is that this is an impossible
objective. At the same time designers often feel put upon because they see
themselves being the ones that will be put on the hook for performance. But that
is not the right reading of the path forward. The correct view is that we need
to reorganize our projects to make them performance focused. There are several
ways to do this but the key is to understand the need for recalibrating the
design/construction process wherein the designer steps back and acts more as the
orchestra leader rather than one doing the performing. However, the process of
stepping back is tricky. It means focusing on the truly important project goals
that are largely ignored in building projects today. And the very idea makes
many designers ill-tempered and all too ready to dispute the need for such
change.
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To mitigate this response, I often try to offer examples of a successful
implementation. An approach I have developed, used successfully, and advocate is
to add a new player, a “performance contractor.” In this process we integrate a
scope of work for this new entity into the specifications and contract documents
as the design is developed. The performance contractor – operating directly
under the GC – takes responsibility for achieving and maintaining the
ultra-efficient performance of the building energy systems. In order to do so
the specifications provide this subcontractor with the authority to pre-approve
equipment submittals, work out details of equipment configuration, and take over
the integration of the optimization control of all systems involved. The
designer orchestrates this effort by establishing the necessary minimum levels
of performance for each piece of energy consuming equipment – at the operating
conditions that will occur most frequently, providing basic equipment
configurations that are sized to meet the expected loads, and establishing a
robust control network over which basic plant control and oversight,
optimization and performance verification can all be accomplished.
All this is not easily accomplished by the designer. Like the conductor of an
orchestra, the designer needs to know what can and cannot be expected from those
performing the work and how best to integrate this all together. This is not a
simple task and too many engineers lack the knowledge about what levels of
performance can be reasonably achieved from various building energy systems. Or
what configurations of equipment are required for optimal performance. But for
those who truly want to succeed in higher performing buildings, there are
resources available to develop the necessary knowledge and with a little thought
about how best to support such a strategy, motivated designers can usually find
ways to implement performance as a focus for their projects.
The problem is that some designers and owners don’t seem to have much motivation
to change. So let’s spread the word that achieving and maintaining
ultra-efficient building energy system operation is possible, but to do so
requires change in the way each of us approach the projects in which we are
involved. Let’s work to be open to new paths for success and be sure not to
shoot the messengers of that needed change.
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