NCEES Practice Problem #510

[RVincent]

Hi All,

I got this one wrong last night, and found that the answer is per the ASME codes. I did not find anything in the MERM about this after an extended search (but then I was also pretty tired at the time). Is this info in the MERM, and I just missed it? Or, should I get a copy of the ASME codes?

Thanks,

Randy

 

[MetroRAFB]

Which afternoon module are you refering to? All three have a #510.

 

[RVincent]

Which afternoon module are you refering to? All three have a #510.

Sorry...I am referring to the Thermal Fluids module.

Thanks.

 

[MetroRAFB]

If it's the HVAC module, Section 41.4 in the MERM explains the methodology of calculating the cooling load from windows, but the nomenclature is different than what's shown in the NCEES problem. The nomenclature in the MERM closely follows the nomenclature in the ASHRAE pocket guide. I actually wrote down the equation shown in the NCEES solution in my ASHRAE pocket guide so I'd have it during the exam in case I ran into a problem with the same nomenclature as in the NCEES problem. You basically have to make the mental leap of equating the "A(SC)(SCL)" term in equation 41.3 in the MERM to the "A(SHGF) term in the NCEES solution. This radiant term makes up the bulk of the cooling load through the windows, the conductive term (U)(A)deltaT makes up a much smaller portion of the cooling load. If you calculate the first term correctly for that problem you'll get 19,080 Btu/hr, which just about rules out all the answers except D.

 

[MetroRAFB]

****! Sorry, I'll look at that one and see if I'm able to help.

 

[MetroRAFB]

I finally got some time to look at this one. I didn't do an extensive MERM search on it, but I'd be shocked if the answer is in the MERM. There will be many question in the depth portions of the exam that will come from other references pertaining to that particular depth subject. I'd recommend getting a copy of the ASME codes if you don't have one already.

The biggest problem with those additional references is that if you don't have time to get familiar with them before the exam, they probably won't help you a great deal. That's the real reason I didn't take the full set of ASHRAE books into the HVAC afternoon when I took the exam. I don't work in HVAC and didn't have time to get familiar with all of those books, so I just took the small ASHRAE pocket guide in with me. It really saved me, there were several depth answers that I was able to get directly out of that reference.

 

[Fordman101]

I brought my ASHRAE manuals to the test and was able to solve some gimme problems in the morning session.