Question

With respect to Refrigeration systems uses onboard:

(a) How do we choose environmentally friendly refrigerants for ships? (6)

(b) How do CFC's, HCFC's, HFC's and natural refrigerants like ammonia and carbon-di-oxide compare in terms of ozone depletion (ODP) and global warming potential (GWP)? (4)

(c) What are the benefits and challenges of using natural or low-GWP refrigerants on marine vessels? (3)

(d) Explain the steps you will take to ensure that release of refrigerant gases from the plant in minimized during normal operation and during maintenance activities. (3)

Answer 1

Part (a)

Environmentally friendly refrigerants are selected based on the following criteria:

Low Ozone Depletion Potential (ODP) – Refrigerants with zero ODP are preferred to comply with the Montreal Protocol (e.g., HFCs, HFOs, natural refrigerants).
Low Global Warming Potential (GWP) – Preference is given to refrigerants with minimal contribution to greenhouse effects (e.g., CO₂, ammonia, hydrocarbons, HFOs).

Additional considerations include safety (toxicity, flammability), energy efficiency, compatibility with system components, and regulatory compliance under IMO MARPOL Annex VI.

✓ Verified Model Answer (Text Solution)

Environmentally friendly refrigerants are selected based on the following criteria: