Category Archives: HVAC Fundamentals

Useful fundamental principles and concepts that apply to HVAC and Building Science

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

Working with the Honeywell W7212 Economizer Controller; Nuances of the Economizer Control Process, Part 2 –Economizer Basics

In this post, I am going to define a few terms related to economizer processes so we are all “on the same page” for what will follow as I move forward with the W7212 discussion. I am writing this at … Continue reading

Posted in Controls, Economizers, HVAC Fundamentals | Leave a comment

Saturated, Multi-Phase Systems and Proof that a Watched Pot Does Actually Boil – Plotting the Data (and a Bit about Logarithmic Scales)

Just when you thought it was safe to come back with out running into yet another post on multi-phase saturated systems. I really do think this will be the last one.  But, it occurred to me that it might be … Continue reading

Posted in Excel Techniques, HVAC Fundamentals, Steam Systems | Leave a comment

Saturated, Multi-Phase Systems and Proof that a Watched Pot Does Actually Boil – Part 4

Now for the fun stuff;  an experiment you can perform at home (for your kids science project maybe?) that demonstrates some of the stuff I have been discussing in the previous posts and also proves that a watched pot does … Continue reading

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Saturated, Multi-Phase Systems and Proof that a Watched Pot Does Actually Boil – Part 3

After looking at the diagrams in the last post and contemplating the title of the current string – Saturated, Multiphase Systems – you may think this all sounds pretty complicated, like something that is totally foreign to you. However, I … Continue reading

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Saturated, Multi-Phase Systems and Proof that a Watched Pot Does Actually Boil – Part 2

Working with REFPROP to develop my Mollier diagrams for water and R134a reminded me of how much we rely on the work of those who have gone before us to do what we do every day.  That made me want … Continue reading

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Saturated, Multi-Phase Systems and Proof that a Watched Pot Does Actually Boil – Part 1

Well, I’m behind on where I had hoped to be on my blog posts, but its been a busy couple of months.  And since this is more of a hobby than not, it tends to run lower on the proverbial … Continue reading

Posted in HVAC Fundamentals, Steam Systems | Leave a comment