Command Commissioning teamed with the Energy Systems Laboratory at Texas A&M University to provide Continuous Commissioning® services at sixteen City of Dallas buildings totaling approximately 2 Mil. SQFT.
The buildings notably included City Hall, Dallas Museum of Art, and Central Library. Command Commissioning performed a detailed investigation of each building to determine potential energy and cost savings opportunities.
One of the largest and most complex buildings included as part of the project was City Hall. During the assessment phase, several operational issues were discovered that resulted in operators continually responding to comfort complaints. The building mechanical system is configured with several subsystems that were not functioning efficiently as a whole. The key efforts in the implementation phase were oriented around utilizing the existing equipment and control systems to provide the occupants with increased comfort in every season and to modify the control sequences to increase the total system efficiency. Additionally, the commissioning issues observed during the assessment phase were tracked until resolution of the issues was confirmed.
The CC® measures implemented at City Hall included optimizing equipment schedules, AHU supply air temperature and flow, zone reheat strategies, chiller staging, chilled water supply temperature and flow, and condenser water temperature.
The whole building energy savings were calculated using a measurement and verification analysis conducted by the Energy Systems Laboratory. The baseline, implementation and post implementation phases of the project were tracked and compared to calculate the savings of all implemented measures for each building. Implementation of the CC® Process at City Hall resulted in $167,610 of accumulated savings from June 2014 to August 2016.
Monthly reports were issued during the Ongoing Monitoring phase of the project. The focus of these reports was on the performance of each CC® measure. Each quarter these observations were documented along with recommended actions to further investigate or resolve deviations from the intended performance.
After implementing a reset schedule for the condenser water temperature setpoint, the value was overridden to maintain a constant temperature, deviating from the implemented measure. As a result, the cooling towers were unable to cool the condenser water to meet the setpoint at higher outside air wetbulb temperatures, and the performance of the chilled water systems decreased.