Category Archives: Air Handling Systems

These posts focus on retrocommissioning findings for air handling systems

A Free Electronic Psych Chart and How to Use It to Plot Basic HVAC Processes

Ryan Stroupe of the Pacific Energy Center recently worked out a deal that allows him to provide a free limited capability version of Hands Down Software’s electronic psych chart.  You can get a copy at this link and a overview … Continue reading

Posted in Air Handling Systems, Economizers, Excel Techniques, HVAC Calculations, HVAC Fundamentals, Psychrometrics, Resource List and other Resources, Weather and Climate Interactions with Buildings and Systems | Leave a comment

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

Retrocommissioning Findings: Scoping a Dental Clinic VAV Reheat System–Part 1

I’m currently involved with a number of field oriented classes in which the instructors mentor the students through a retrocommissioning process on a system in an existing building in real time.  Based on past experience with this process, I have … Continue reading

Posted in Air Handling Systems, Retrocommissioning Findings | Leave a comment

System Effect–Dealing with the Point Where the Fan Meets the Duct

I am going to take a break from my string on building a psych chart to do a post on System Effect in support of one of the classes Ryan Stroupe and I teach at the Pacific Energy Center.   If … Continue reading

Posted in Air Handling Systems | 1 Comment

Retrocommissioning Findings: Economizer Mixed Air Plenum Stratification–Overview

Happy New Year! I hope everyone had a nice holiday and now are getting back into the swing of things.  Kathy and I had a great holiday and are just finishing putting away the Christmas decorations, which always seems to … Continue reading

Posted in Air Handling Systems, Economizers, Retrocommissioning Findings, Weather and Climate Interactions with Buildings and Systems | 2 Comments

Retrocommissioning Findings: Make Up Air Handling System Simultaneous Heating and Cooling – The Clues – #7 – The Obvious Stuff

This post brings us full circle from where we started this string by looking at the obvious clues you might encounter out in the field, just like the MAU with the textbook design and textbook retrocommissioning opportunity I discussed at … Continue reading

Posted in Air Handling Systems, Retrocommissioning Findings | Leave a comment