HVAC · Practice-Exam-2 · Problem 78PDFSolution in PDF ↓
HVAC · Practice-Exam-2 · Problem 78
Problem & Solution
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Topic: Heat exchanger / heat transfer — During the process of condensing in a counterflow heat exchanger, the enthalpy of R410A is reduced from 125BT to 42BT per pound.
Approach: So let's start with picture, a schematic really is best here.
Key values: 240 psi, , foot squared, 500 gpm delta t or anything like that
Reference: search the reference handbook for the search term heat exchangers,
✅ Answer: C
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Student questions asked in live office hours about this problem
OH 102: HVAC: Full Practice Exam #78
Q: Shouldn't the T1 for our 410A be 105 degrees Fahrenheit? Why do we exclude the superheated region for this problem?
A: Yeah, this is a good question and it's super nuanced. I just thinking about it more after I saw your question. It would be pretty tough to figure this out, but I think I can get you there.