Category Archives: Controls

Posts with information about control systems.

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

The Persistence of the Benefits of Commissioning (Plus a Few Pictures of Legacy Instruments)

As you probably have noticed if you follow the blog, I love finding old instruments in my travels. I have even been lucky enough to save a few of them from the dumpster, like this resonant frequency-based tachometer …   … Continue reading

Posted in Controls, Mentoring and Teaching, Operations and Maintenance, Pneumatic Controls, Retrocommissioning Findings | Leave a comment

Learning about Relay Logic; What’s a Relay?

Author’s Note:  I edited this to put in pictures with better contrast for the relay images further down the post and for some reason, instead of just replacing the original post, the system put it up as a new post.   … Continue reading

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Control System Fundamentals

This post evolved to support a string of posts I will start next to support an exercise in one of the classes I am involved with at the Pacific Energy Center.  In those posts, we will look at how you … Continue reading

Posted in Controls, HVAC Fundamentals, Operations and Maintenance, Pneumatic Controls | 2 Comments

Economizers–The Physics of Linkage Systems

In the post before the previous, I was discussing an economizer performance problem in a facility we worked with as a class in Monterey California.  One of the problems was related to the mechanics of motion in the linkage system … Continue reading

Posted in Air Handling Systems, Controls, Economizers, Pneumatic Controls | Leave a comment

Economizers–The Physics of a Mixed Air Plenum

I’ve been working on a post that shows how a scatter plot technique can be used to assess the performance of an HVAC airside economizer.  It’s based on comparing a plot of outdoor air temperature vs. mixed air temperature for … Continue reading

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

Applied Psychrometrics – the Psych Chart Dry Bulb Temperature Axis (Plus a Bit about Dry Bulb Thermometers)

This post looks at dry-bulb temperature and how it is measured.  Then, it looks at how you plot a dry-bulb temperature on a psych chart.  The links below will jump you to the various topics in the post. What Is … Continue reading

Posted in Controls, Psychrometrics | Leave a comment