# HVAC exam vs Thermo-fluids exam



## tim1981

I've been accepted to take the test in April and I'm not sure what test to take. I didn't realize there were different depth sections for HVAC and thermo-fluid. I always thought of HVAC as an application of thermo-fluid.

I work in HVAC as a consulting engineer. I've been working in this position for the past 4 years.

I am currently working towards my Master's degree in Mechanical Engineering, with a concentration in thermo-fluid systems.

I would not rule out the possibility of switching careers once I finish my master's to do something more techincal in the thermo-fluid field. If I go this route, would having my PE in thermo-fluid as opposed to HVAC help me in any way? Or should I just pick whichever one sounds easier? In my experience studying graduate level thermo-fluids while working in HVAC, thermo-fluids is way harder. Is that the case for the tests as well? I've read they are equally easy, but I don't see how that could be given that HVAC is a basically a dumbed-down real world application of the thermo-fluid physics.

Any advice on where to look to decide which test to take? HVAC sounds easier to me, but the overlap that studying for the test would have with my education if I went the thermo-fluid route sound appealing to me. Any advice, links, etc would be appreciated. Thanks!


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## ikesdsu

tim1981 said:


> I've been accepted to take the test in April and I'm not sure what test to take. I didn't realize there were different depth sections for HVAC and thermo-fluid. I always thought of HVAC as an application of thermo-fluid.
> 
> I work in HVAC as a consulting engineer. I've been working in this position for the past 4 years.
> 
> I am currently working towards my Master's degree in Mechanical Engineering, with a concentration in thermo-fluid systems.
> 
> I would not rule out the possibility of switching careers once I finish my master's to do something more techincal in the thermo-fluid field. If I go this route, would having my PE in thermo-fluid as opposed to HVAC help me in any way? Or should I just pick whichever one sounds easier? In my experience studying graduate level thermo-fluids while working in HVAC, thermo-fluids is way harder. Is that the case for the tests as well? I've read they are equally easy, but I don't see how that could be given that HVAC is a basically a dumbed-down real world application of the thermo-fluid physics.
> 
> Any advice on where to look to decide which test to take? HVAC sounds easier to me, but the overlap that studying for the test would have with my education if I went the thermo-fluid route sound appealing to me. Any advice, links, etc would be appreciated. Thanks!




I don't know if I would call HVAC dumbed down thermo fluids physics  but heres the thing, when you get your PE it isn't for a specific type of mechanical engineering. You are a professional mechanical engineer. I guess if I was you, I would do the HVAC test since you have been doing it for the last 4 years. While the HVAC and Thermo/fluids are very similar, this test is really real world type problems, not the typical "classroom" derive a equation and look up numbers. I am a consulting mechanical engineer but I know that I wouldn't be able to do the some the real world type problems that are in the thermo test like designing pumps, ect, but I can do the HVAC side because of famillarity.


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## tim1981

ikesdsu said:


> tim1981 said:
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> 
> 
> I don't know if I would call HVAC dumbed down thermo fluids physics
Click to expand...



No? I'm just comparing the types of HVAC calculations I do for work (e.g. btuh=500*GPM*deltaT) vs the types of calculations I do for fluids and heat transfer graduate classes (e.g. navier-stokes equations). By virtue of being an application, as opposed to a hard science, it would make sense for HVAC to be easier.

Are the tests equally hard? If so, the thermal fluid test might be easy compared to what I'm doing for graduate school. On the other hand, studying for the HVAC portion would be more helpful professionally, and I borrowed all the sample tests for this section from a coworker.


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## ikesdsu

tim1981 said:


> ikesdsu said:
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> 
> 
> tim1981 said:
> 
> 
> 
> I don't know if I would call HVAC dumbed down thermo fluids physics
> 
> 
> 
> 
> 
> Click to expand...
> 
> 
> 
> No? I'm just comparing the types of HVAC calculations I do for work (e.g. btuh=500*GPM*deltaT) vs the types of calculations I do for fluids and heat transfer graduate classes (e.g. navier-stokes equations). By virtue of being an application, as opposed to a hard science, it would make sense for HVAC to be easier.
> 
> Are the tests equally hard? If so, the thermal fluid test might be easy compared to what I'm doing for graduate school. On the other hand, studying for the HVAC portion would be more helpful professionally, and I borrowed all the sample tests for this section from a coworker.
Click to expand...





I agree that the basic equations that you use every day like 1.08 CFM delta T or btu=500 GPM delta T are really easy but I bet if you were doing thermo fluids on a daily basis you would find that they use equally easy rules of thumb that get them close enough for daily work. My opinion is that you should be carefull to compare what you are doing in grad class to what you are doing in the field. While both are important they are very different. One is the pure sience, and the other is the hands on knowledge. The PE test is all about the hands on knowledge, the stuff that you have just learned by being burned or the "trial by fire" learning that seems to be so common in the consulting feild.

I guess I should revise what I put in your post in a different thread. If you have been doing HVAC the last four years, I would guess that you would be knowledgable in that area. What part of the test you passed doesn't show up on your certificate, just that you passed. I would go HVAC.

I guess


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## tim1981

Thanks for your reply. I understand what you're saying about real world math being easier than grad school. Part of the dilemma is over weather I'm more qualified to take the thermo exam because I'm currently in the habit of higher level math in those subjects, or whether I'm more qualified to take the HVAC exam because I'm currently in the habit of applying that knowledge. Your response about the PE being all about hands on knowledge leans me towards HVAC for this reason.

Two things I don't get though:

1) I'm comparing the two sections now:

http://cdn2.ncees.co/wp-content/uploads/2012/11/PE-Mec-HVAC-Oct-2008.pdf

http://cdn4.ncees.co/wp-content/uploads/2012/11/PE-Mec-Thermal-Oct-2008.pdf

A lot of the applications are the same: Cooling towers, boilers, condensers, pumps, compressors, fans, and controls are all on both tests. Also on the thermo test I see pressure vessels and heat exchangers, which are used in HVAC but not on the HVAC test. The only applications on the thermo test that aren't related to HVAC are turbines and engines. The systems section of both tests are also very similar. What exactly is the real difference? Why do they even have a separate test for HVAC?

2) Since these tests are so similar, they line up with the same sections of the MERM, so I don't really see how I would study for one any different than the other. The MERM sections for Fluids, Thermo, Heat Transfer, Power Cycles, Heat Transfer, and HVAC seem to cover what I'd need for either test. Therefore, using the MERM (and companion practice problems book) alone, how would I know what questions I might see on one test and not the other? I'd like to take a sample test in both and see which I do better in, but they seem to be pulling from the same set of questions.

To answer the question you asked in the other response, I'd be confident on the psychometric problem, but I've yet to learn how to solve the cooling tower problem (I have not designed a system with a cooling tower before). Did you pose that question assuming the cooling tower was another HVAC problem or a thermo problem? Cooling towers are on both tests, as far as I can tell


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## ikesdsu

tim1981 said:


> Thanks for your reply. I understand what you're saying about real world math being easier than grad school. Part of the dilemma is over weather I'm more qualified to take the thermo exam because I'm currently in the habit of higher level math in those subjects, or whether I'm more qualified to take the HVAC exam because I'm currently in the habit of applying that knowledge. Your response about the PE being all about hands on knowledge leans me towards HVAC for this reason.
> 
> Two things I don't get though:
> 
> 1) I'm comparing the two sections now:
> 
> http://cdn2.ncees.co/wp-content/uploads/2012/11/PE-Mec-HVAC-Oct-2008.pdf
> 
> http://cdn4.ncees.co/wp-content/uploads/2012/11/PE-Mec-Thermal-Oct-2008.pdf
> 
> A lot of the applications are the same: Cooling towers, boilers, condensers, pumps, compressors, fans, and controls are all on both tests. Also on the thermo test I see pressure vessels and heat exchangers, which are used in HVAC but not on the HVAC test. The only applications on the thermo test that aren't related to HVAC are turbines and engines. The systems section of both tests are also very similar. What exactly is the real difference? Why do they even have a separate test for HVAC?
> 
> 2) Since these tests are so similar, they line up with the same sections of the MERM, so I don't really see how I would study for one any different than the other. The MERM sections for Fluids, Thermo, Heat Transfer, Power Cycles, Heat Transfer, and HVAC seem to cover what I'd need for either test. Therefore, using the MERM (and companion practice problems book) alone, how would I know what questions I might see on one test and not the other? I'd like to take a sample test in both and see which I do better in, but they seem to be pulling from the same set of questions.
> 
> To answer the question you asked in the other response, I'd be confident on the psychometric problem, but I've yet to learn how to solve the cooling tower problem (I have not designed a system with a cooling tower before). Did you pose that question assuming the cooling tower was another HVAC problem or a thermo problem? Cooling towers are on both tests, as far as I can tell




I agree they are very very similar especially in the morning but if the afternoon they change. If you look at the princilples, while they are similar they are weighted differently, like in HVAC the thermodymanics is 7% and the psychometrics is 15% while in the thermo fluilds thermo is 10% but psychometrics is a small part of 3%, maybe 1%?. Same as the applications in HVAC the systems includes air distribution and ERV's while Thermo fluids is mostly pump stuff. So overall the topics are mostly the same each type is weighted differently.

good catch onthe cooling towers I missed that. I wonder if they are simiar but they would focus on a different part? Airflow and conditions in HVAC Vs. pumps and water flow in thermo fluids?

I guess if you have access to the 6 minute solutions books you could look at those, they are actually broken up by afternoon and morning sessions for each of the tests. That may give you a better idea what they expect and I found at least to me, these questions seemed closest to the difficulty of the questions on the tests. (both times I took it  )


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## tim1981

I'm taking the HVAC test. I looked through the Power Cycles chapters in the MERM this morning and now I'm thinking that the Thermal-Fluid exam might be more catered to power plant engineering. Power plants and HVAC are both applications of thermal-fluid physics, and it wouldn't make sense for one test to be theory while the other is focused on one application, so I'm guessing the thermal-fluid test is focused on power plant applications and/or other non-HVAC applications. If they're both equally focused on applications vs theory, my graduate school experience isn't going to help me and I should take the test that focuses on the applications I'm familiar with.

Thanks for your help, ikesdsu


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## ikesdsu

tim1981 said:


> I'm taking the HVAC test. I looked through the Power Cycles chapters in the MERM this morning and now I'm thinking that the Thermal-Fluid exam might be more catered to power plant engineering. Power plants and HVAC are both applications of thermal-fluid physics, and it wouldn't make sense for one test to be theory while the other is focused on one application, so I'm guessing the thermal-fluid test is focused on power plant applications and/or other non-HVAC applications. If they're both equally focused on applications vs theory, my graduate school experience isn't going to help me and I should take the test that focuses on the applications I'm familiar with.
> 
> Thanks for your help, ikesdsu




Awesome, now it is time for you to kick the tests butt.

Good luck


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## komeso

tim1981 said:


> I'm taking the HVAC test. I looked through the Power Cycles chapters in the MERM this morning and now I'm thinking that the Thermal-Fluid exam might be more catered to power plant engineering. Power plants and HVAC are both applications of thermal-fluid physics, and it wouldn't make sense for one test to be theory while the other is focused on one application, so I'm guessing the thermal-fluid test is focused on power plant applications and/or other non-HVAC applications. If they're both equally focused on applications vs theory, my graduate school experience isn't going to help me and I should take the test that focuses on the applications I'm familiar with.
> 
> Thanks for your help, ikesdsu


I agree! ....... also, I've heard/read that HVAC is the easiest test from all 3!!!!


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## GA PE

I found the T/F to be more straight forward with most of the problems coming out of the MERM which I passed OCT 2012. The HVAC questions could come anywhere out of the MERM and the AHRAE manuals and were more complex questions than necessary for an 8 hour exam with 80 questions ( I took the HVAC Apr 2012 and did not pass). I recommend the T/F afternoon, but to each his own.


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## MapuaTech

based on my experience on April 2012 exam, i am sitting in front of mechanical hvac examinee and he had a lot of books on his utility box mostly ashrae and carrier manuals. As we go through exams i heard him and he keeps getting his manuals from his box. I guess he had a lot of problem finding the right reference. After the exam, as we go out of exam center, i heard him talking to his friends that he encountered tons of problems that nowhere to find in his references. I hope he passed it.


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## ikesdsu

I made the same mistake the first time I took the test. You can't rely on your books to help you pass. There isn't enough time to search through a bunch of books for an equation.

The second time I took the test I brought the MERM, the three 6m solution books and the four ASHRAE books. I didn't even open the ASHRAE books so I really only used the MERM and the 6M solution books.

I can't stress this enough, you have to know in general where the equations are before you get to the test.


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