In the blogs at csemag.com

David Sellers, P.E., senior engineer with the Portland, Ore. office of Facility Dynamics Engineering, and CSE's “A Field Guide for Engineers” blogger, has several valuable new postings. Sellers has rapidly followed up a seven-part series on damper tests with several posts, including the following:

“Controlling the Environment Requires Understanding the Environment,” focuses on the damper test findings and discusses some of the implications in terms of performance and energy consumption across the country.

Next, “Same Problem Different Issues” discusses the impact of an economizer that is stuck in the 100% outdoor air position on two identical systems, one of which is located in San Diego and the other in Key West, Fla.

“Unit Conversion Constants; Not Alway Constant” is a blog that resulted from a call from Seller's colleague, William Acker, president of Acker & Assocs., Green Bay, Wis., and an expert on energy analysis, air emissions and water-vapor transmission and condensation. Acker pointed out that many engineering calculations, including the built-in calculations in some measuring equipment, use engineering constants that are based on the properties of the measured variable at a fixed condition. For instance, a differential pressure based air flow meter might base its flow calculations on air at standard sea level conditions. As a result, measurements may need to be corrected.

“Measuring Outdoor Conditions; Not So Easy as You Might Think” is a supplemental blog that takes another look at the damper test series.