TFS · Practice Exam 2 · Problem 14PDFSolution in PDF ↓
TFS · Practice Exam 2 · Problem 14
Problem & Solution
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- Problem: Water enters a 100 ton cooling tower at 130 degrees and leaves at 105 degrees.
- Approach: Assume no losses.
- Key values: 60 %, 80 %, 000 BTU, 100 %
- Reference: reference handbook
- ✅ Answer: D
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Student questions asked in live office hours about this problem
OH 75
Q: I used the sensible heat gain equation Q = 500GPM × ΔT with Q = 1.2 million BTU and ΔT = 25°F for water to find GPM, but didn't get the correct answer—shouldn't this approach work given that Q for air equals Q for water?
A: You correctly calculated the condenser water flow rate circulating through the chiller's cooling loop, but that's not what the problem asks for. The question wants makeup water flow rate—the small amount needed to replace water lost to evaporation in the cooling tower—not the total system circulation rate, which is much larger.