Summary of Results of OAE Field Tests and Demonstrations
The WBD’s Outdoor Air Economizer (OAE) module has been field tested at several large office and laboratory buildings, mostly in the Western States (Washington, Colorado, and California). Summary of results are provide in the table below. For more on field test results please refer to the individual paper or reports provided in the field test section of the web site.
The OAE diagnostician found problems with almost all AHUs monitored. The problems ranged across faulty sensors, mis-positioned sensors, stuck dampers, unscheduled operations, excess ventilation, and inadequate ventilation. At one site, the OAE was installed immediately after the building was occupied and yet the OAE found several problems that should have been detected during commissioning. It is likely that some of the AHUs may have multiple simultaneous faults. The OAE diagnostician highlights a single predominant fault, in cases where an AHU has multiple simultaneous faults. Unless the first fault is corrected and new data then processed, the other faults may not manifest depending on the prevailing indoor and outdoor conditions and whether the first fault masks other faults (e.g., a faulty temperature sensor will make all diagnoses based on its measurements meaningless).
In most cases, the problems identified by the OAE were visually verified and confirmed by the building operator, but the problems were seldom corrected. As shown in table below, the annual cost impacts estimated by the OAE, ranged from $130 to $16,000. For AHUs with temperature sensor problems, the OAE cannot estimate the cost impact because estimating impacts relies on measured values of temperature as inputs. With the exception of a few cost estimates, all of them were estimated by the cost module in the OAE diagnostician. The OAE diagnostician uses the cost of energy, efficiency of equipment and expected performance to estimate the impact of improper operations. In cases, where heating is provided as reheat in the zones, the OAE does not estimate heating impacts; therefore, some of the estimates provided in the table are low by the corresponding impact on heating.
Click here for the "Enhancing Building Operations through Automated Diagnostics: Field Test Results" paper. (PDF 508KB)