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Engineering, 11.07.2019 01:20 rach1314

A4-m-high and 28-cm-diameter cylindrical column of a house is cooled to 15°c during a cold night and heated again during the day by being exposed to ambient air at an average temperature of 32°c with an average heat transfer coefficient of 14 w/m2. k. the column is made of concrete (k 0.79 w/mk, ? -5.9 x10" m2/s, ? 1600 kg/m3, and c,-0.84 kj/kg-k). using analytical one-term approximation method (not the heisler charts), determine: a)-how long it will take for the column surface temperature to rise to 30°c, b)-the amount of heat transfer until the center temperature reaches to 32°c, and c)- the amount of heat transfer until the surface temperature reaches to 30°c.

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