A dormitory at a large university, built 50 years ago, has exterior walls constructed of Ly = 25-mm-thick sheathing with
Posted: Mon May 16, 2022 7:10 am
A dormitory at a large university, built 50 years ago, has exterior walls constructed of Ly = 25-mm-thick sheathing with a thermal conductivity of ks = 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 Tooi = 22°C and T., = 0°C, respectively. The inner and outer convection heat transfer coefficients are hi = 5 W/m2K and ho = 25 W/m2.K, respectively. = = The heat flux through the original walls is 602.04081 W/m2 The heat flux through the retrofitted walls is 217.68101 W/m2