Description

Inadequate initial commissioning, the inability of the building operators to adequately monitor all building equipmentand systems, and lack of proper maintenance or retrocommissioning lead to inefficient operations and reduced lifetimes of the heating, ventilating, air-conditioning (HVAC), and other energy-using equipment in buildings. Regularly scheduled manual maintenance and re-commissioning can help address these problems but can be labor intensive and perceived as expensive. Automated proactive commissioning and diagnostic technologies could help address two of the main barriers to commissioning and good maintenance—labor requirements and the costs associated with them. Automated proactive commissioning and diagnostic tools could reduce both the cost and time associated with commissioning, as well as enhance the persistence of commissioning fixes. Automation even offers the potential to go well beyond just monitoring and detecting faults to automatically correcting problems by compensating for sensor problems, reconfiguring controls, or changing control algorithms dynamically.

In this paper, we present a generic model for automated continuous commissioning and then delve in detail into one ofthe processes, proactive testing for fault isolation, which is key to automating commissioning. The automated commissioning process uses passive observation-based fault detection and diagnostic techniques, followed by automated proactive testing for fault isolation, automated fault evaluation, and automated reconfiguration of controls to continuously keep equipment controlled and running as intended. Only when hard failures occur or a physical replacement is required does the process require human intervention, and then sufficient information is provided by the automated commissioning system to target manual maintenance where it is needed.

We then focus on fault isolation by presenting detailed logic that can be used to automatically isolate faults in valves,a common component in HVAC systems, as an example of how automated proactive fault isolation can be accomplished.Although automated passive fault detection and diagnostics have been tested in the field on actual equipment, the proactive process described in this paper has only been tested against simulations and has not yet been field tested. We conclude the paper with a discussion of how this approach to isolating faults can be applied to other common HVAC components and their automated commissioning, followed by a summary of key conclusions of the paper conclusions of the paper.

Units: Dual

Citation: ASHRAE Transactions, vol. 113, pt. 2

Product Details

Published:

2007

Number of Pages:

12

File Size:

1 file , 2.5 MB

Product Code(s):

D-LB-07-004