System Integration: Challenges In Existing Buildings
March 11, 2015
Today's briefing comes from Jim Sinopoli, managing principal of Smart Buildings LLC. Existing buildings usually have a lot of issues that must be resolved during the integration project. Many of these issues will affect a system integration project but are really matters unto themselves. One example is the lack of a naming convention for building equipment or tags for data points. Without a naming convention, similar equipment may have many different names — a recipe for confusion. Given that dilemma, any system integration project will require someone to spend time developing a naming convention and then translating the existing equipment names over to the new naming convention.
Another challenge is the BAS network architecture. Over time BAS controllers and field devices are replaced or added to the BAS network, especially in large buildings or campuses. Typically the work is completed by a series of different technicians from the local office of the manufacturer, and many times not a lot of forethought is given to the network architecture and impact on the throughput for the network. The result over time is the BAS network may become unbalanced with too much traffic on some trunks affecting network throughput and the acquisition of data point values.
Fault detection applications, a useful new tool, can also present complications. Fault detection is the process of analyzing real time data from an HVAC system against a set of rules which address the relationships and interoperations of different HVAC equipment. While it has been shown to save energy and significantly improve operations, it doesn't just come "right out of the box" as if it were a software program you would install on your PC. Every building and HVAC system is slightly different and you end up having to customize the fault detection rules. That's not necessarily a bad thing, as the customized rules are likely to be more accurate and based on client needs, but customization requires time, possibly extending schedules.
Facility managers should also be wary of applications without a plan. System integration can facilitate applications such as consolidated alarm management where the alarms from all the building control systems can be monitored and managed from a single application. The easiest part of deploying an alarm management application may be acquiring the alarm data from the building systems. The more difficult part is having an alarm management plan underlying the application. The alarm management plan usually lists the alarms, prioritizes them, details the response for each alarm, groups various types of alarms, identifies escalation plans, etc. Unfortunately many facility managers don’t have a formal alarm management plan.
Finally, facility managers should be selective in data acquisition. It's unlikely that a facility manager needs all the data points in every system. Focus instead on just the important data points that support key performance indicators or specific analytic routines. The downside to acquiring all the data as opposed to selective data is that the database becomes bloated with information that will never be used. Acquiring that data adds traffic to the network, affecting throughput — especially with older BAS controllers and data acquired from slow RS485 networks.
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