🔍 Key Concepts

• Effect of insulating scale deposits on heat transfer efficiency in a heat exchanger • Relationship between overall heat transfer coefficient, temperature difference, and heat flow • What happens to hot side vs. cold side outlet temperatures when heat transfer becomes more difficult but flow rates stay the same

💭 Think About

• If scale forms on the water side, does heat move more easily or less easily from the lube oil to the water? Think of scale as insulation. • With poorer heat transfer, will the cooling water be able to pick up more heat or less heat from the oil as it passes through? How will that affect the water outlet temperature? • If the water side is picking up less heat from the lube oil, what happens to the lube oil temperature as it leaves the exchanger, assuming its inlet temperature and flow rate are unchanged?

✅ Before You Answer

• Remember that scale acts like insulation, reducing heat transfer between the two fluids. • Keep in mind that flow rates are constant, so any change is due only to the change in heat transfer, not more or less water or oil. • Think about energy balance: if the cooling water is removing less heat, what must happen to the oil’s temperature to maintain that balance?