🔍 Key Concepts

• Heat transfer between two substances at different temperatures • Difference between heating/cooling a space vs changing the temperature of a fluid • Common shipboard uses of lube oil coolers, jacket water coolers, and condenser cooling

💭 Think About

• Ask yourself: Does a heat exchanger mainly affect the room air, or does it work on fluids inside a system? • Which option describes a device that can be used both to heat and to cool, depending on operating conditions? • Think about where you’ve seen heat exchangers on board: What are they doing to the water, oil, or refrigerant flowing through them?

✅ Before You Answer

• Verify which choice talks about one fluid affecting another fluid’s temperature. • Eliminate any options that only mention air in a space rather than a working fluid in piping. • Check that the option you pick could apply in both directions (raising or lowering temperature), not just cooling.