4.5 2D NonSteady State Heat loss through a Chimney Wall The figure below shows a cross section through a chimney. Consider a gas temperature of 400 C in the chimney and 25 *C outside. The inside heat transfer coefficient is 100 and the outside coefficient is 10 The chimney is made from brick with a thermal conductivity of 1.0 Determine how long it takes node 8 to reach 200 C. Cp = 840 x p=2000" W m2K mK kg 0.25 m 3 7 10 9 10 Tas * To, at 11 12 12 he 1 m 12