USCG Exam PracticeThermodynamics and heat exchangers
According to the first law of thermodynamics, what happens to energy that appears to 'disappear' in a real process?
- A. It is destroyed by friction and cannot be accounted for
- B. It is stored permanently within the system as entropy
- ✓ It is converted to a less useful form, most often low-temperature heat rejected to the environmentCorrect
- D. It is transferred to the working fluid as increased enthalpy
Why C is correct
DOE-HDBK-1012 §1-3 states that energy can be neither created nor destroyed; energy that seems to disappear has been converted to a less useful form, most often low-temperature heat rejected to the environment. The first law prohibits destruction of energy.
Cited:DOE-HDBK-1012 §1-3