Author Archives: David Sellers

A Control Logic Exercise and a Way to Get Comfortable With Navigating SketchUp Models

As many of you know, I have been experimenting with using SketchUp models as a way to teach EBCx techniques.  I frequently use them in my classes and also have started to post self-study exercises that are based on the … Continue reading

Posted in Controls, Retrocommissioning Findings, SketchUp Model Based Self Study | Leave a comment

A New Resource for Looking at Climate Data

So, some of you are probably thinking Thank God he has finally put something up that gets rid of that picture of him and Kathy on Christmas.  That did stay up for a bit longer than I had planned at … Continue reading

Posted in PowerPoint Techniques, Weather and Climate Resources | Leave a comment

Happy Holidays

Hoping you are having as much fun this holiday season as Kathy and I are having. Meanwhile, thanks for supporting the blog and Happy Holidays.    David Sellers Senior Engineer – Facility Dynamics Engineering

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Exploring Evaporative Cooling–Part 1

If you look at a psych chart closely, you will notice that the constant wet bulb lines are not exactly parallel to the constant enthalpy lines. Note that to make things more visually apparent in this blog post, for most … Continue reading

Posted in Air Handling Systems, HVAC Calculations, HVAC Fundamentals, Psychrometrics | Leave a comment

Universal Translator Workshop

Sorry to disappoint Star Trek fans, but this is not a workshop about a device used to decipher and interpret alien languages into the native language of the user.  Having said that, if you are into building systems commissioning and … Continue reading

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So Many Tools; So Little Time (Unless You Happen to Live in the Bay Area and are Looking for a Job Working with Them)

The picture above is a panorama shot of the tool lending library at the Pacific Energy Center.  As I took the picture, I was literally thinking so many tools, so little time, wishing I could spend some of my day … Continue reading

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Cooling Tower Flow Distribution and Variable Flow in Condenser Water Systems

One of my current obsessions is how subtle details regarding how you pipe a cooling tower can make a huge difference in how the flow is distributed.  I’ve been interested in that for a long time actually as the result … Continue reading

Posted in Condenser Water Systems, HVAC Fundamentals, Operations and Maintenance, Retrocommissioning Findings | Leave a comment