A dormitory at a large university, built 50 years ago, has exterior walls constructed of Ls= 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 T∞,i= 22°C and T∞,o= -2.5°C, respectively. The inner and outer convection heat transfer coefficients are hi= 5 W/m2·K and ho= 25 W/m2·K, respectively. a. what is the heat flux through the original walls in W / m^2 b. what is the heat flux through the retrofitted wall in W
A dormitory at a large university, built 50 years ago, has exterior walls constructed of Ls= 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 T∞,i= 22°C and T∞,o= -2.5°C, respectively. The inner and outer convection heat transfer coefficients are hi= 5 W/m2·K and ho= 25 W/m2·K, respectively.
a. what is the heat flux through the original walls in W / m^2
b. what is the heat flux through the retrofitted wall in W / m^2
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