A 4-m-high and 6-m-wide wall consists of a long 18-cm x 30-cm cross section of horizontal bricks (k= 0.72 W/m-K) separated by 3-cm-thick plaster layers (k = 0.22 W/m-K). There are also 2-cm-thick plaster layers on each side of the wall, and a 2-cm thick rigid foam (k = 0.026 W/m K) on the inner side of the wall. The indoor and the outdoor temperatures are 38°C and -4°C, respectively, and the convection heat transfer coefficients on the inner and the outer sides are hy= 10 W/m2K and hz = 20 W/m2K, respectively. Assuming one-dimensional heat transfer and disregarding radiation, determine the rate of heat transfer through the wall (in W). Foam Plaster Brick

Consider a large plane wall of thickness 2L=20mm. Both surfaces of the wall are convectively cooled by the surrounding coolant at To = 250°C with a heat transfer coefficient of h= 1100 W/m².K. A fuel element of a nuclear reactor is considered in the shape of this large plane wall with given constant thermal properties as thermal conductivity k = 30 W/m.K and a = 5 x 10-6m²/s. It is known that heat is generated uniformly within the element at a volumetric rate of q = 1x 107W /m³. A departure from the steady-state conditions associated with normal operation will occur if there is a change in the generation rate. Consider a sudden change to q2 = 2 x 107W/m³. Assuming steady one-dimensional heat transfer along the wall, use the explicit finite- difference method to show how to calculate temperature To at 1.2 sec and temperature Ts at 1.5 sec. (show which equation to use and the calculations in details)

A 4-m high and 6-m-wide wall consists of long 15-cm x 20 cm cross section horizontal bricks (k of 0.69 W/m K) separated by 2-cm thick plaster layers (k of 0.2 W/m K). There are also 2-cm-thck plaster layers on each side of the brick and a 3-cm-thick rigid foam (k of 0.025 W/m K) on the inner side of the wall. See figure below. The indoor and the outdoor air temperatures are 18 and -8oC, respectively. Convective heat transfer coefficient for inside and outer surfaces are 8 and 22 W/m2 K, respectively. Assume 1-D heat transfer. Neglect radiation   assume any plane wall normal to the x-direction is isothermal, draw the thermal circuit and calculate the heat transfer rate through the wall

There is a 1.20-cm-thick stagnant air pocket. A) What thickness of cork would have the same R-factor as the stagnant air pocket? The thermal conductivity of air is 0.0230 W/m·K and of cork is 0.0460 W/m·K.in cm  B) What thickness of tin would be required for the same R-factor as a 1.20-cm-thick stagnant air pocket? The thermal conductivity of air is 0.0230 W/m·K and of tin is 66.8 W/m·K . in m i asked how to do this but got the wrong soloution