Global sensitivity analysis of the building energy performance and correlation assessment of the design parameters

Abstract: The world’s energy use in buildings (residential and commercial) accounts for around 40% of the worldwide energy consumption, and space heating is the responsible for half of the energy need in the building sector. In Europe, only a small share (less than 10%) of existing buildings was built after 1990. Most of the building stock does not satisfy the recent energy technical standards; in addition there is a very low trend to construct new buildings in the last years. Renovation of the existing buildings is a feasible option to reduce the energy need in Europe, but finding the optimum solutions for a renovation is not a simple task. Each design parameter differently influences the final energy need of buildings and, furthermore, the different variables are differently correlated each other. Building refurbishment will benefit from a tool for the selection of the best measures in term of energy need. This work, through a global sensitivity analysis, aims at determining the contribution of the design parameters to the building energy demand and the correlation between the different variables. The considered parameters are related to the improvement of the thermal transmittance of both the opaque envelope and the windows, the solar transmittance of the glazing surfaces, the window size, the thermal inertia of the internal walls and the external sunshades for windows. Several dynamic simulations have been performed varying the design parameters from different starting conditions. Finally, due to the large number of cases elaborated, an inferential statistical analysis has been performed in order to identify the predominant factors and the correlation between the design parameters in a global context.