A radiator wall measuring 2 m by 3 m (WxH) is held a temperature of 125 °C. Straight aluminium fins (k = 175 W/mK) are to be mounted on the wall. The fins are 5 cm in length and 0.8 mm thick. The system is allowed to convectively transfer heat to ambient air at 20 °C with a heat transfer coefficient of 20 W/m2K.
a. Determine the efficiency of a single fin (?f).
b. Determine the heat transfer from a single fin. Fin running along the width.
c. Determine the fin effectiveness (?f). Fin running along the width.
d. Determine the heat transfer if the radiator wall does not have any fins.
e. Determine the overall surface efficiency if you had 10 fins running along the length (H).
f. You are requested to design a fin system that will reject 3 times (3X) more than the bare radiator wall. Determine the number of fins needed. Run the fins along the length (H) of the wall.
i. How would the solution change if the fins were running across the width?
ii. How would the solution remain the same if the fins were running across the width?
g. If copper was used for the design in “part f” would the number of fins decrease/remain the same/increase? Explain your answer.