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A heat exchanger was required to cool a liquid from 150℃ to 110℃, but the outlet temperature was increased by 3℃ every month for same heat transfer. What should have been the fouling factor if UD = 80?

A heat exchanger was required to cool a liquid from 150℃ to 110℃, but the outlet temperature was increased by 3℃ every month for same heat transfer. What should have been the fouling factor if UD = 80? Correct Answer 94

We can tell that for the heat transferred to be equal, UD×47 = UC×40 or UC = 80×47/40 = 94.

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