Cost-Effective Demonstration of Automated Commissioning and Tuning
Veronica Adetola | United Technologies Research Center
This project will demonstrate a cost-effective and scalable variable air volume (VAV) commissioning and PID control tuning toolset for building HVAC systems. Existing HVAC systems often have degraded performance due to undetected faults and inappropriate tuning of control loop parameters. Research has shown that such degradation can increase HVAC energy consumption 15-20% and adversely impact indoor air quality. Building retro- and recommissioning is a recognized way to identify and resolve these issues in existing buildings and return them to their original operating performance. Unfortunately, traditional building re-commissioning methods to identify and address such faults are highly manual and expensive, limiting their adoption. This project will demonstrate the effectiveness of highly automated tools that evaluate the performance of ventilation systems and provide a report of faulty equipment requiring attention as well as implement optimal local control-loop parameters to prevent excessive equipment cycling. The demonstration will measure energy consumption of multiple buildings before and after application of these tools to prove out energy savings. The required labor will also be recorded and ultimate return on investment calculated. The ultimate objective is to demonstrate a >20% reduction in baseline HVAC energy consumption while achieving a <3 year payback period.
The Automated Commissioning Tool automatically runs tests on HVAC ventilation equipment. The results are analyzed and a report of faulty terminal units is generated. Once faulty units are fixed, the PID Auto-Tuning Tool can run additional automated tests to determine and implement optimal equipment PID control-loop tuning parameters. These highly automated tools achieve a substantial reduction in labor and cost-savings over manual inspection of equipment and trial and error controls tuning. These tools have been demonstrated on multiple buildings to date. Testing on over 5,000 VAVs has shown typical fault rates of 10-20% in the field and substantial energy savings and comfort benefits once these faults are fixed. PID control-loop auto-tuning has demonstrated a 40-90% reduction in control set-point error and reduction in actuator cycling. This project aims to demonstrate these tools on multiple buildings at Marine Corps Air Station (MCAS) Beaufort to validate the ease of installation, number of faults identified, tool accuracy and resulting improvements in energy efficiency and building comfort. In particular. this demonstration will ensure the tool meets the specific requirements for application to military facilities.
The expected benefits are a demonstrated >20% savings for HVAC system energy consumption, a >40% reduction in equipment cycling due to improved controls tuning, and improvements in indoor air quality and comfort. These benefits are applicable to the nearly 32,000 Department of Defense (DoD) building HVAC systems where cooling and heating (e.g. from chillers and boilers) is provided to Air Handling Units (AHUs) and Variable Air Volume (VAV) or similar terminal units. A 20% HVAC system energy reduction, via application of the technology set across these existing DoD facilities would offer an annual savings potential of >$120M and an annual energy savings of 1 billion kWh.