USCG Exam PracticeRefrigeration and air conditioning
On a large vessel, a chilled-water air conditioning system is preferred over a direct-expansion system primarily for which reason?
- A. Chilled-water systems use ammonia refrigerant, which has superior thermodynamic properties
- B. Chilled-water systems eliminate the need for a condenser, reducing machinery space requirements
- ✓ Chilled water distributes cooling throughout the ship via water piping rather than long refrigerant linesCorrect
- D. Chilled-water systems do not require a compressor, relying instead on absorption cooling
Why C is correct
NAVEDTRA 14075 §6-7 states that a chilled-water system is favored on larger vessels because it distributes cooling with water piping rather than long refrigerant lines. Running refrigerant piping throughout a large vessel introduces leak risk, pressure drop, and oil return complications that are avoided by keeping the refrigerant circuit local to the machinery space and distributing chilled water instead.
Cited:NAVEDTRA 14075 §6-7