The topic of measurement made me realize the importance of measurement and feedback as we work on designing, commissioning, operating, and servicing BAS. A good control system, by definition, utilizes feedback for accurate control. For example, a DDC loop that is modulating a chilled water valve will typically use the associated setpoint and discharge air temperature as inputs to the loop.

It is also important that as system designers, we get feedback on how our designs operate. Unfortunately, we often end up working “open loop” and don’t have that feedback. As a result, it is not uncommon for systems not to be achieving our design goals in terms of cost, efficiency, comfort, and performance. So how do we get good feedback? Here are a few suggestions:

• Contractor feedback. We get continuous feedback from our contractors, often starting before the project is released and throughout the negotiation process. But the best place to get feedback is often while we are reviewing submittals. Of course, you need to be careful about this information. Some of it is very useful information that may help us design the next project better, and other times it is simply pushback due to items the contractor may have overlooked.
• Commissioning. Ideally, we do commissioning on all of our control projects. This provides us with the ability to work with the contractor and owner to make sure that the system works as it was intended. Much of the feedback from this process is invaluable in refining both the current and future designs.
• Beyond warranty end. Unfortunately, once a project is complete and into its warranty phase, our involvement typically ends. It occasionally may extend past this point as we provide services such as measurement and verification on energy efficiency. What is frustrating is that systems and strategies may get overridden either intentionally or inadvertently as the project goes into warranty. Ideally, our measurement process would continue with the owner, working with them to help provide ongoing assistance perhaps with some form of continuous training or commissioning process, or with the use of software-based analytics program.

The other big question is what to measure. We typically measure a series of parameters that range from project cost and variance from budget on to the amount of energy saved and the conformance to parameters including uptime and comfort.

I agree with Gates. There is a need for continued measurement and feedback, since only with this continued input can we improve.