TFS · Thermodynamics · Problem 15PDFSolution in PDF ↓
TFS · Thermodynamics · Problem 15
Problem & Solution
Video Synthesis
- Problem: Saturated liquid R123 at a pressure of 60 PSIA is pumped to a pressure of 100 PSIA and remains saturated liquid.
- Key step: Saturated liquid R123 at a pressure of 60 PSIA is pumped to a pressure of 100 PSIA and remains saturated liquid.
- Watch out: So when we say that we're going to travel from a state one which is a saturated liquid to a state two at a higher pressure which is still a saturated ...
- Result: So for state two we know the pressure is a 100 PSIA and we know that it's saturated liquid so we can say that H2 is going to be equal to HF at 100 PSI...
- ✅ Answer: C
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Student questions asked in live office hours about this problem
OH 119 · April 28, 2026
Q: For an R-123 problem where fluid pumps from 60 psia to 100 psia as saturated liquid, then expands isenthalpically — how do you read the P-H diagram to find quality at the final state?
A: Plot State 1 on the saturation curve at 60 psia and State 2 at 100 psia (saturated liquid), then drop straight down (constant enthalpy) to State 3. Quality at State 3 = (H₃ − H_F)/(H_G − H_F), where H_F and H_G are read from the saturation curve at 60 psia. The chart can locate the states, but the final quality calculation still requires a numerical step — the table method avoids chart-reading imprecision and is generally preferred for higher accuracy.