USCG Exam PracticeBoiler and steam propulsion fundamentals
Which of the following best describes the difference between sensible heat and latent heat as applied to boiler feedwater?
- A. Sensible heat changes the phase of water from liquid to steam; latent heat raises the temperature of the water
- ✓ Sensible heat raises the temperature of water without changing its phase; latent heat changes the phase at constant temperatureCorrect
- C. Sensible heat is the heat content of superheated steam; latent heat is the heat content of subcooled liquid
- D. Sensible heat and latent heat are interchangeable terms for the total enthalpy of saturated steam
Why B is correct
Sensible heat changes a substance's temperature without changing its phase, while latent heat changes its phase at constant temperature. At atmospheric pressure, the latent heat of vaporization is approximately 970 Btu per pound. These are distinct quantities and are not interchangeable. (DOE-HDBK-1012 §1-2)
Cited:DOE-HDBK-1012 §1-2