An assessment of the impact of building envelope design on the tradeoff between embodied and operating energy

The building envelope encompasses an important share of construction materials and may dictate the embodied energy in buildings. This paper performs parametric analysis to evaluate the affect of several envelope design parameters on the operational and embodied energy consumption of the building. These parameters include southern wall glazing ratio, northern wall glazing ratio, glazing type, and wall assembly. The wall assembly design variables in turn include interior insulation thickness, interior insulation material, exterior insulation material, exterior insulation thickness, and outmost layer material. The other parts of the wall assembly remained constant in all simulation runs. A single store residential building with 150 m2 built-up area is considered as a case study to perform calculations. Based on the simulation results, Increasing the glazing ratio in the southern and northern walls from 0 to 80% results in a 12.7% and 15.7% increase in the total energy consumption, respectively. Moreover, employing triple pane windows raises the embodied energy compared to the double pane windows by 27.5%. However, they result in a 4.44% reduction in total energy consumption due to their better thermal insulation properties. Finally simultaneous variation of the glazing ratio and wall assembly reveled the minimum possible total energy consumption during the life cycle of the building can be obtained by providing aerogel as insulation material with 100 mm thickness in the interior insulation layer and 60 mm in the exterior insulation layer, fiber cement panels as the outmost layer and triple pane windows.