Implementation of natural refrigerants on cruise ships. A review of rules and regulations from two Classification Societies

This report delves into the challenge of implementing heat pumps, refrigeration systems
and chillers (vapour compression systems) that use natural refrigerants, in the maritime
sector. The first part gives a context, introducing the international organisations aim to
reduce greenhouse gas emissions from the shipping industry, and defining the topic of
refrigerant selection. The documents on safety requirements for vapour compression
systems onboard, issued by the classification societies Lloyds Registers and DNV, are then
summarised. The focus is on the implications for systems using natural refrigerants. It is
found that a "case-to-case" evaluation of almost all these systems must be applied. In the
last section the communication with the classification societies is summarised. The goal is
to contribute to clearer and more standardised requirements on the use of natural
refrigerants, to facilitate their safe implementation, environmental-friendly and long-term compliant maritime refrigerants.