Problem 2.9: A boiler produces steam at atmospheric
From Chapter 2 Problem Set. Level 3: System Integration.
Question
A boiler produces steam at atmospheric pressure. The feedwater enters at 50°F. How many total BTUs per pound are required to produce steam? Break your answer into the sensible heat portion and the latent heat portion.
Answer
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Sensible: 1 lb × 1.0 BTU/lb°F × (212°F − 50°F) = 162 BTU. Latent: 970 BTU. Total: 162 + 970 = 1,132 BTU per pound of steam. Latent heat accounts for 86% of the total energy investment.