Find the overall heat transfer coefficient Ui (W/m2 C) based on the inner surface area of the tube. A double-pipe heat exchanger is made of an inner copper tube with an internal diameter D = 1.2 cm and external diameter Do = 1.6 cm, and an outer tube with a diameter of 3.0 cm. The inner surface of the tube has a reported convection heat transfer coefficient of hi = 700 W/m C, whereas the outer surface has a coefficient of h. = 1400 W/m C. The inner and outer fouling factors were set as 2000 and 5000 W/m C, respectively. . 141

Find the overall heat transfer coefficient Ui (W/m2C) based on the inner surface area of the tube. A double-pipe heat exchanger is made of an inner copper tube with an internal diameter D1=1.2cm and external diameter D0=1.6cm, and an outer tube with a diameter of 3.0 cm. The inner surface of the tube has a reported convection heat transfer coefficient of hj=700W/m2C, whereas the outer surface has a coefficient of ho0=1400W/m2.C. The inner and outer fouling factors were set as 2000 and 5000W/m2C, respectively. a) 159 b) None C) 952 d) 238 e) 317 f) 120 g) 60 h) 476 i) 634