Ventilation and Refrigeration Systems

Ventilation Systems

• Ventilation systems expel hot, humid, or polluted air from enclosed spaces, preventing hazardous gas buildup.
• Exhaust vents are crucial for expelling air.
• Fans move air throughout the ship's interior, including cabins and storage areas.
• Ducts direct air flow.
• Ventilation systems are essential for maintaining air quality, supporting crew comfort, and operating various onboard systems.
• Natural and mechanical ventilation are two primary types of ventilation systems used on ships.
• Air handling units prepare air before distribution to living/working spaces.

Refrigeration Systems

• The primary function of a refrigeration system is to remove heat.
• Refrigeration systems operate based on heat transfer principles.
• The compressor compresses refrigerant in a vapor-compression cycle.
• The expansion valve reduces refrigerant pressure.
• Other components include condensers and evaporators.
• Refrigerants like R-410A are hydrofluorocarbons (HFCs) and have zero ozone depletion potential.
• Vapor-compression cycles use compression, condensation, expansion, and evaporation.
• Absorption cycles utilize heat energy to drive refrigeration.
• Refrigeration systems in buildings are primarily used for air conditioning.
• Food processing significantly relies on refrigeration systems.
• Safety devices like pressure relief valves protect against excessive pressure.
• Factors like compressor and condenser size affect system efficiency.
• Low refrigerant charge is indicated by low pressure and temperature fluctuations.

Heat Exchangers

• Heat exchangers transfer heat between fluids on ships.
• Plate heat exchangers are known for their compact design and efficiency.
• Common problems that reduce heat exchanger efficiency include corrosion and fouling.
• Ship heat exchangers often utilize corrosion-resistant materials like mild steel or copper-nickel alloys.
• The fluid needing cooling or heating typically flows through the tubes in a shell and tube heat exchanger.
• Lube oil coolers cool lubricating oil in ship engines.
• Malfunctioning heat exchangers can lead to reduced efficiency or engine overheating.
• Brazed plate exchangers are commonly used for smaller systems on ships.
• Freshwater generators on ships provide fresh water for drinking, cooling systems, and boiler feed.