<![CDATA[The provision refrigeration system is essential for preserving food supplies on board vessels during extended voyages. This study analyzes the causes of non-optimal evaporation in the provision refrigeration system on board LPG/C Mariner and proposes corrective measures to restore normal system performance. During the author's sea practice period, the food storage room temperatures deviated significantly from the instruction manual specifications: the meat and fish compartment rose from the required –21°C to –3°C, while the vegetable and lobby storage rose from the normal range of 2–8°C to 17°C. Investigation using a descriptive qualitative approach with problem-solving analysis identified two principal causes. First, the storage room temperature instability was attributed to a damaged expansion valve with a clogged orifice that restricted refrigerant flow to the evaporator, compounded by refrigerant leakage in the circulation system piping that reduced the total refrigerant charge available for heat absorption. Second, the non-optimal evaporation process was caused by a malfunctioning oil separator, in which a blocked lubricating oil return passage and a broken internal spring allowed lubricating oil to enter the refrigerant circulation system. The oil contamination formed ice particles and frost deposits on the evaporator coil pipes, progressively reducing the heat transfer surface area and evaporation efficiency. Corrective measures included replacement of the damaged expansion valve orifice, welding repair of leaking refrigerant pipes, overhaul and component replacement of the oil separator, and application of electric defrosting heater and hot gas defrost systems to remove ice accumulation from the evaporator coils and refrigerant piping.]]>
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