As promising as fault detection and diagnostics is, facility managers need to take a close look at their buildings and at the capabilities of available software tools before rushing out to install a fault detection and diagnostics application. Some of the issues and concerns involved in implementing fault detection and diagnostics are as follows:
Lack of Data. Fault detection and diagnostics tools rely on data from building automation systems. If there are not enough sensors, if the sensors are inaccurate, or if the building has a legacy control system and for some reason accessing the BMS database or controllers is difficult, there can be issues with obtaining the accurate data required.
Rules Specific to Building Systems. The rules apply to specific HVAC relationships and equipment, and facility managers need to be assured that their specific building systems are or can be addressed by the fault detection and diagnostics software application. Many products start with a standard set of rules, which may address similar or smaller buildings or HVAC configurations, and then add rules developed by others or by the supplier of the fault detection and diagnostics tool.
For larger buildings, fault detection and diagnostics does not come right out of the box. Almost every sizable building and HVAC system is slightly different, so the rules have to be customized. That's not necessarily a bad thing, as the customized rules are likely to be more accurate and based on specific building needs, but customization requires additional installation time.
Handling Fault Information. Facility management organizations need to decide how best to handle the fault detection and diagnostics information. A "fault" identified by a fault detection and diagnostics application indicates that the system is not performing optimally. This is different from a system alarm indicating some criticality and need for immediate action. In many facility management organizations, both alarms and faults automatically trigger a work order, but do so identifying different priorities for the work order. Other organizations set the faults aside and then periodically meet to discuss the remedies.
Using the Diagnostic Data. Many of the fault detection and diagnostics software tools can provide information to the technician or engineer regarding potential corrective actions. This information needs to be integrated into the work order system, which may be one application in a whole suite of facility management applications, in order to use the information effectively.
Fault Detection Draws Industry AttentionThe idea of fault detection and diagnostics for HVAC systems is not new. Research, development and testing of fault detection approaches have been around for about 20 years or so. What is new is the increased interest in and actual use of fault detection. The Microsoft application is a case in point. Another example of industry approval of data analytics and fault detection and diagnostics came in October 2011, when the U.S. Green Building Council announced a technology agreement that would allow building owners to use an automated fault detection tool with the LEED Online platform, thus supporting the commissioning of buildings. USGBC's interest is that the tool generates reports for LEED Online, including diagnostic functions and faults during the building's performance period. Another sign of industry interest comes from a Lawrence Berkeley National Laboratory study on monitoring-based commissioning, which uses building diagnostics. Lawrence Berkeley established an average energy savings of 10 percent through the use of monitoring-based commissioning, with as much as 25 percent in some cases. — Jim Sinopoli |
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