Post by slaythepe on Jan 6, 2023 10:26:40 GMT -5
Hi all,
In case you didn't know, every once in a while, NCEES updates the errata sheet for their practice exams, but makes no "official" announcement (that we know of). Check your discipline exam errata in their website
The Mechanical TFS and MDM were updated November 22nd, and 23rd, respectively. The HVAC&R errata was last updated 2/8/2021.
The previous TFS errata was dated 4-4-2022. Here is what they fixed for this version (we had notified them about all of these corrections they needed):
* Question 26: they changed the location of point 1 in the figure to upstream of the pump, as it should be.
* Question 28: they fixed the drawing in the question to show that the compressor inlet is the fan discharge.
* Solution 28: They made some changes to their previous solution, but the solution presented in the errata is still all wrong. We will email them again to help them fix the multiple issues still present here.
* Question 72: they fixed the error of asking for the maximum heat transfer rate but then calculating the actual heat transfer rate.
* Solution 34: they fixed the error when calculating outside air load using (h_oa - h_mix) and now they're doing it correctly with (h_oa - h_ra). Strangely, they changed the variable name from h_mix (incorrect) to h_ra (correct) but they are using the same value as before, 30.9 Btu/lbm (which is h_mix) instead of what it should be, 28.9 Btu/lbm (which is h_ra). So their numerical solution is still wrong, FYI. If you do it right, the coil leaving wet bulb temperature should be 50.9F instead of the 51.7F of their solution. It's "a wash" because you'd still pick the right choice. But, in principle, they are wrong.
* Solution 64: they fixed the typo in the equation and now the Higher Heating Value (HHV) appears in the denominator as it should be.
In case you didn't know, every once in a while, NCEES updates the errata sheet for their practice exams, but makes no "official" announcement (that we know of). Check your discipline exam errata in their website
The Mechanical TFS and MDM were updated November 22nd, and 23rd, respectively. The HVAC&R errata was last updated 2/8/2021.
The previous TFS errata was dated 4-4-2022. Here is what they fixed for this version (we had notified them about all of these corrections they needed):
* Question 26: they changed the location of point 1 in the figure to upstream of the pump, as it should be.
* Question 28: they fixed the drawing in the question to show that the compressor inlet is the fan discharge.
* Solution 28: They made some changes to their previous solution, but the solution presented in the errata is still all wrong. We will email them again to help them fix the multiple issues still present here.
* Question 72: they fixed the error of asking for the maximum heat transfer rate but then calculating the actual heat transfer rate.
* Solution 34: they fixed the error when calculating outside air load using (h_oa - h_mix) and now they're doing it correctly with (h_oa - h_ra). Strangely, they changed the variable name from h_mix (incorrect) to h_ra (correct) but they are using the same value as before, 30.9 Btu/lbm (which is h_mix) instead of what it should be, 28.9 Btu/lbm (which is h_ra). So their numerical solution is still wrong, FYI. If you do it right, the coil leaving wet bulb temperature should be 50.9F instead of the 51.7F of their solution. It's "a wash" because you'd still pick the right choice. But, in principle, they are wrong.
* Solution 64: they fixed the typo in the equation and now the Higher Heating Value (HHV) appears in the denominator as it should be.