The convective heat transfer coefficients on the inside and outside of a -std type L copper tube

The convective heat transfer coefficients on the inside and outside of a ½-std type L copper tube are 150 Btu/hr-ft2-°F and 450 Btu/hr-ft2-°F, respectively. The tube is 4-ft long. An ethylene glycol solution flows on the outside of the tube and Refrigerant-22 is on the inside. The average temperature of the copper tube is 100°F. Determine the UA product for this tube for the following conditions,

a. When it is first put into service (i.e., clean)

b. After being in service for one year without maintenance (i.e., fouled)

c. Repeat parts

(a) and (b), assuming that the thermal resistance of the copper tube is negligible.