🔍 Key Concepts

• Heat source for the evaporator in a typical main engine jacket water system • How the jacket water cooler relates to the evaporator on the piping diagram (series vs. parallel) • Whether the evaporator is heated by engine jacket water or by seawater leaving another cooler

💭 Think About

• Trace the flow of main engine jacket water from the engine outlet through the heater, jacket water cooler, and evaporator. In what order do they appear? • Look at the lines feeding the evaporator: do they branch off from the same supply/return headers as the jacket water cooler, or must the water pass through one unit before reaching the other? • Check what fluid enters the evaporator shell/heat side. Is it labeled as jacket water, seawater, or something else?

✅ Before You Answer

• Verify which component (heater, jacket water cooler, or evaporator) receives hot jacket water directly from the engine outlet. • Confirm from the drawing whether the evaporator’s jacket water connections are on common manifolds (parallel) or in a straight-through path (series) with the jacket water cooler. • Ensure you are not confusing the jacket water side with the seawater cooling side—the evaporator heat source comes from only one of these.