Objectives  This paper presents the form and operation characteristics of a refrigerant water loop system of a large ship.

  Methods  To address the flow distribution problem under different operating modes, an scaled experimental platform is developed for the system. Experiments on the backup pump water supply and single-pump and multi-pump combined water supply are carried out in order to study the flow rate distribution characteristics of the system.

  Results  According to the results, when the backup pump in the middle of the ship supplies water to other zones, the flow rates of the users in each zone are all higher than 90% of the designed values, with the hydraulic imbalance degree ranging from 0.89 to 1.02. When a single pump supplies water to all users of the ship, the flow rates of the users range from 20.0% to 37.1% of the designed values, with a peak imbalance ratio higher than 40%. For the multi-pump combined water supply mode, the optimal operating conditions of the two-pump, three-pump and four-pump combined water supply modes can meet the water demands of different loads respectively, with a maximum imbalance ratio between zones of less than 15%.

  Conclusions  This study may provide a reference for the operation and control of the practical system.