The exit temperature is right, the fan power is wrong.
Extracted text: Problem 08.141 - River water to cool riverside house A house built on a riverside is to be cooled in summer by utilizing the cool water of the river, which flows at an average temperature of 15°C. A 19-m-long section of a circular duct of 20-cm diameter passes through the water. Air enters the underwater section of the duct at 45°C at a velocity of 3 m/s. Assuming the surface of the duct to be at the temperature of the water, determine the outlet temperature of air as it leaves the underwater portion of the duct. Also, for an overall fan efficiency of 55 percent, determine the fan power input needed to overcome the flow resistance in this section of the duct. Air хС, 3 m/s 15°C Air River, 15°C The exit temperature of air is The fan power required to overcome this pressure drop is 22.7175 °C. 0.1516 W.