TFS · Heat Transfer · Problem 7PDFSolution in PDF ↓
TFS · Heat Transfer · Problem 7
Problem & Solution
Video Synthesis
Topic: Pipe flow / fluid mechanics — A clean new domestic hot water heater uses 25 PSIA saturated steam to heat 50 gpm of water from 60 degrees to 130 degrees.
Approach: the way we'll start is you can search the reference handbook for fouling or you can also search for the somewhat long phrase or part of this phrase overall heat transfer coefficient for concentric tub
Key values: 25 PSIA, 25 psi, 50 gpm of water from 60 degrees to 130 degrees
Reference: reference handbook
✅ Answer: A
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Student questions asked in live office hours about this problem
OH 108
Q: In Heat Transfer 7, the solution video shows iteration is required for a steam heat exchanger problem, but by setting up the equality of the two duty equations with cold outlet temperature as the only unknown, I solved it directly without iteration and got 107°C—is this approach as accurate as iterating?
A: You're absolutely right—iteration isn't strictly necessary. By holding the outlet temperature as a variable on both sides of the equation rather than making an assumption on one side, you set up a single equation where the same unknown appears on both sides, which requires algebra (including exponential and logarithm functions) but yields the exact answer in one pass. Great algebraic approach, and I'll update the solution video.