Adormitory at a large university, built 50 years ago, has exterior walls constructed of l5 = 25-mm-thick sheathing with a thermal conductivity of k3 = 0. 1 w/m. k. to reduce heat losses in the winter, the university decides to encapsulate the entire dormitory by applying an li = 25-mm-thick layer of extruded insulation characterized by ki = 0. 029 w/m k to the exterior of the original sheathing. the extruded insulation is, in turn, covered with an lg = 5-mm-thick architectural glass with kg = 1. 4 w/m. k. determine the heat flux through the original and retrofitted walls when the interior and exterior air temperatures are tinfity, i = 22 degree c and tinfity, 0 = -20 degree c, respectively. the inner and outer convection heat transfer coefficients are hi = 5 w/m2 k and h0 = 25 w/m2 k. respectively.