September 2010 |
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Why is it that control systems
don’t work? |
Paul Ehrlich & Ira Goldschmidt |
We recently had a chance to catch up with an industry acquaintance and were describing some of the energy efficiency programs we were designing. Imagine our surprise when he responded with this question: “Why is it that it seems like control systems in commercial buildings never work?” At first we were taken aback by the question, after all we see controls and BAS as being a key element to the delivery of a sustainable, high performance building. Unfortunately, we quickly realized that he was right. In evaluating existing buildings from new to vintage, we almost always find partial to complete failure of control systems. Why does this happen, and, more importantly, why do we think that it is possible to have systems that work? Our observation is that the failure of these systems has little to do with the availability of quality controllers or sensors, but has to do completely with the process involved in designing, building, and running these systems. To elaborate, root causes are as follows:
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Design: Many control systems fail in the design
phase. Often design engineers may view controls and BAS as an afterthought, with
little detail being put into designs. Perhaps it is easier to just modify a
vendors guide spec or to re-use an existing document with minor updates. The
biggest problem we see is in the details. What exactly are the required
sequences? How will the systems be optimized? What exactly should the user
interface look like? What points are required? A well thought out, detailed and
appropriate design is the key to a successful system. How this is accomplished
may be a good topic for several future columns, but it likely involves training,
a strong systems focus and the appropriate changes to fees and schedules.
Installation: There are some excellent controls contractors and system
integrators in practice today. The challenge is to find these suppliers and to
work closely with them to make sure that systems get properly detailed,
documented, installed, programmed and commissioned. Working closely with good
contractors can give great results. Unfortunately the corollary to this is also
true, resulting in poorly installed, tested and documented systems. Of course
even a great control solution won’t work with a poorly designed or installed
mechanical system. Attention to proper installation and commissioning is
critical for high performance operation.
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Operations: Once the project is completed it falls to building operations to
make it work properly throughout the lifespan of the building. Providing
building operators with the right processes, focus, tools and training can
result in a platform for sustained efficiency. Even a great operator isn’t going
to be able to get a control system that has been improperly designed or
installed to work though.
The answer to our acquaintance’s question is that control systems can work well
and that should be an expectation for any project. Focus on thorough control
design and installation, coupled with good training and tools for continuous
commissioning and monitoring. These are the keys to the delivery of high
performance building operation platforms.
About the Authors
Paul and Ira first worked together on a series of ASHRAE projects including the BACnet committee and Guideline 13 – Specifying DDC Controls. The formation of Building Intelligence Group provided them the ability to work together professionally providing assistance to owners with the planning, design and development of Intelligent Building Systems. Building Intelligence Group provides services for clients worldwide including leading Universities, Corporations, and Developers. More information can be found at www.buildingintelligencegroup.com We also invite you to contact us directly at Paul@buildingintelligencegroup.com or ira@buildingintelligencegroup.com
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