In the Blogs at csemag.com

David Sellers, who blogs “A Field Guide For Engineers” posted the first part of a discussion on damper tests at the end of May, and has already posted Part 7B. “I recently had a chance to test the flow vs. damper blade position characteristics for the AHU1 economizer dampers at the Pacific Energy Center (PEC),” Sellers said. “We discovered a few interesting things, including that theory didn't match reality, at least for our test.”

In Part 2, he looked at the scoping process that led his researchers to develop the test, and he said that readers may find these techniques useful in their own projects. Part 3 looked at techniques that allowed the researchers to assess the performance of the economizer dampers in an air-handling unit. In the post, he discussed why low damper velocities and non-linear damper performance might be cause for concern with respect to economizer damper performance. In Part 4, the researchers said that economizer damper velocity affects the ability of outdoor air and return airstreams associated with an economizer process to mix. Higher velocities translate to more momentum, allowing one airstream to penetrate the other and promote mixing.

Part 5 launched into the testing background, and Part 6 introduced the notion that minimum outdoor air requirement for the facility fell into three components: air required for ventilation purposes, air required to make up for the kitchen hood exhaust, and air required to ensure positive pressurization in the entry lobby. Finally, Parts 7A and 7B describe the test results.