5.12 A counterflow heat exchanger is being used to cool a flow of hot water using a cold 20% ethylene glycol solution. The hot water enters at 80°F with a volumetric flow rate of 400 gpm. The ethylene glycol solution enters the heat exchanger at −10°F and leaves at 15°F. The ethylene glycol solution is flowing at a volumetric flow rate of 300 gpm. The overall heat transfer coefficient for the heat exchanger is found to be 155 Btu/h·ft2·°F. Determine the following:

a. Outlet temperature of the water (°F)

b. Heat transfer rate between the water and ethylene glycol solution (Btu/h)

c. Required heat transfer area of the heat exchanger (ft2)