The vertical rear window of an automobile is of thick- ness l = 8 mm and height h = 0.5 m and contains fine- meshed heating wires that can induce nearly uniform volumetric heating, /m3). (a) consider steady-state conditions for which the inte- rior surface of the window is exposed to quiescent air at 10°c, while the exterior surface is exposed to air at −10°c moving in parallel flow over the sur- face with a velocity of 20 m/s. determine the vol- umetric heating rate needed to maintain the interior window surface at ts, i = 15°c.

Acommercial grade cubical freezer, 4 m on a side, has a composite wall consisting of an exterior sheet of 5.0-mm thick plain carbon steel (kst= 60.5 w/m k), an intermediate layer of 100-mm thick polyurethane insulation (kins 0.02 w/m k), and an inner sheet of 5.0- mm thick aluminium alloy (kal polyurethane insulation and both metallic sheets are each characterized by a thermal contact resistance of r 2.5 x 104 m2 k/w. (a) what is the steady-state cooling load that must be maintained by the refrigerator under conditions for which the outer and inner surface temperatures are 25°c and -5°c, respectively? (b) for power saving purpose, which wall material should be increased/reduced in. thickness in order to reduce 50% of the cooling load found in part (a)? redesign the thickness of the proposed material. 177 w/m-k). adhesive interfaces between the q=575.93 w