4-67 A 30-cm-diameter, 4-m-high cylindrical column of a house made of concrete (k = 0.79 W/m-K, a = 5.94 × 10-7 m2/s, p = 1600 kg/m3,and c, = 0.84 kJ/kg-K)

cooled to 14°C during a cold night is heated again during the day by being exposed to ambient air at an average temperature of 28°C with an average heat transfer coefficient of 14 W/m2-K. Using the analytical one-term approximation method, determine (a) how long it will take for the column surface temperature to rise to 27°C, (b) the amount of heat transfer until the center temperature reaches to 28°C, and (c)the amount of heat transfer until the surface temperature reaches 27°C.