Airside economizer damper control requires close coordination and integration with the system's heating and cooling systems to maximize the energy efficiency of the system. Common controls-related issues, and their corresponding fixes, include:
In general, first determine the intended operation of the airside economizer system. Review the original construction documents and consult with your operating staff to see how the system is currently programmed to operate. Investigate and implement optimization opportunities based on this exercise. Then, periodically test the system to determine if it's performing as intended and take corrective action when it's not. When testing the control sequences, be sure to test them in all operating modes (heating, economizer cooling, integrated economizer and mechanical cooling, and mechanical cooling with minimum outside air).
As a final note, your building automation system (BAS) can be a powerful tool to help monitor the performance of the economizer system. Periodically collecting and analyzing BAS trend data can be a good way of viewing system performance. X-Y scatter plots are often more telling than time-series plots, which can be confusing. Neither will show what problem exists, only that there is a problem requiring investigation. Be sure to filter the data to show "fan on" operation only, and also be sure that your BAS temperature and enthalpy sensors are calibrated.
Airside economizers can save a significant amount of energy, but they need to be maintained for their "free cooling" energy benefits to be realized.
Dave Moser, P.E., is a senior engineer at PECI. He provides engineering services for a diverse range of projects and programs at PECI, all centered on building energy efficiency. His experience includes implementing and managing the technical aspects of utility existing building commissioning programs, leading in-building existing building commissioning projects, and supporting research projects. You can reach him at firstname.lastname@example.org.
Take Good Care of Airside Economizers to Realize Free Cooling Benefits
Common Problems in Airside Economizer Design and Construction
Fixes for Common Airside Economizer Operational Problems
Fixes for Common Issues With Airside Economizers and Control Systems