🔍 Key Concepts

• Jacket water cooling system on a diesel engine – what fluid is being cooled and what removes the heat • Difference between sensible heat (temperature change with no phase change) and latent heat of vaporization (heat involved in changing liquid to vapor or vapor to liquid) • In a typical heat exchanger between jacket water and sea water, which side is the primary purpose: cooling jacket water or heating sea water?

💭 Think About

• Look at where label "3" is located in the diagram: which lines connect to it, and which fluid (jacket water or sea water) passes through it? • Ask yourself whether the jacket water in a normal engine cooling circuit is supposed to boil/condense, or just change temperature while staying liquid. • For each answer choice, decide whether it describes a device whose main job is to cool the jacket water, or to cause a phase change, or to warm another fluid instead.

✅ Before You Answer

• Verify that jacket water remains liquid in normal operation (no boiling, no condensation) and therefore involves removal of sensible heat only. • Confirm that a cooler’s primary purpose in this system is to remove heat from the jacket water, not to raise the sea water temperature for its own sake. • Check whether latent heat of vaporization would apply here – does this system have any component where water is intentionally evaporated or condensed?