Juan C. Ramirez, PhD, P.E.

​The Top Five Topics Every HVAC PE Candidate
​Needs to Master
​

After having mentored hundreds of students to success with the HVAC PE exam, I have concluded that the students most likely to pass are those that understand the following fundamental topics: Energy Balances, The Vapor Compression Refrigeration Cycle, Psychrometrics, Load Estimating, and familiarity with the relevant tables and graphs in the reference handbook.

• The Energy Balance. This concept is key to just about every single thermodynamics and fluid mechanics problem you will encounter. Energy in must equal energy out. Seems simple enough, right? Well… depends. Are you dealing with ideal gases? Liquids? Heavy vapors such as refrigerants or steam? A mixture of vapor and liquid? There are nuances associated with each one and navigating them is crucial.
• The Vapor-Compression Refrigeration cycle (VCRC). The importance of this topic cannot be overemphasized. Judging from feedback from recent customers, the VCRC is the queen of the exam. You need to know your VCRC facts cold (pun intended). Look at this graph. Can you name all four states off the top of your head? Hint: Point 2 is “compressor discharge”
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Follow-up question: Do you know what each of the three horizontal double-arrow lines represent? Hint: one of them is the condenser duty.

Representation of the ideal VCRC on a Pressure-Enthalpy Diagram

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• Psychrometrics. Nobody should be surprised that the science of moist air is a heavily weighted topic in the HVAC exam. The lines on the chart associated with all psychrometric processes should be seared into your retinas.
• The old-school methods of load estimating: For this exam, you won’t be doing any Radiant Time Series or Heat Balance Method calculations, although you sure do have to know what those are. You will, however, use the methodology behind Manual-J type load estimating: the CLF/CLTD method. This method was removed from the ASHRAE Handbook of Fundamentals, and last appeared in the 1997 edition, so your PE exam study resources must cover this technique.
• All the tables and graphs in the reference handbook. Our philosophy is that if NCEES decided to include a table or graph in the reference handbook, then it’s “fair game” when it comes to the exam.
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  • Do you know how to use the tables for refrigerant pipe sizing?
  • Do you understand the purpose of the tables and graphs for circulation rate and refrigerant flow in liquid overfeed systems?
  • Do you know how to use the “Zone Air Distribution Effectiveness” table?

​I have carefully crafted a course that covers all these must-knows and much more, to help you walk into the exam with confidence and the peace of mind of knowing all your bases are covered.

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Author

I’m Juan C. Ramirez, PhD, P.E., a licensed mechanical engineer and the founder of Slay the PE. I earned my PhD in Mechanical Engineering from the University of Iowa and a Master’s degree from Missouri S&T, with a career focus on HVAC&R, Thermal Fluid Systems, and heat transfer. Before launching Slay the PE, I spent nearly two decades in engineering consulting and forensic failure analysis, investigating mechanical system failures, fires, and explosions across industrial, commercial, and residential settings. Today, I build practical, exam-aligned PE prep to help mechanical engineers pass the HVAC&R and TFS exams with confidence.