The impact of climate change on Building Energy Simulation (BES) uncertainty - Case study

Climate change and global warming are two major concerns over the globe today, and the rapid change in climate became more sensible as it impacts diverse industries and disciplines. Buildings share of the global energy use exceeds 40%, and buildings’ Green House Gas (GHG) emmissions resembles one-third of global GHG emmissions (Tranchard, 2017); hence, Building Energy Simulation (BES) process became an essential step during building design, to study and minimize whole buildings’ energy use, and consequently minimize buildings’ carbon footprint. A significant, yet underestimated, input to the BES process is the weather data; BES process normally uses historical weather data in the form of a weather file to simulate the building’s outdoor conditions, those outdoor conditions impacts the amount of thermal load on the building, and therefore they significantly impact building’s estimated annual energy use. Today, with the rapid change in the outdoor weather conditions year after year, using those historical weather data files must be questioned, as they impact the estimated energy use, and consequently put what’s deemed as the “optimum energy use” in question. Using those historical weather data is hence expected to increase BES degree of uncertainty. This paper studies and quantizes the impact of weather data accuracy on building’s annual energy performance. The paper takes an experimental approach by simulating an office building located in Cairo - Egypt using weather data file, and using actual weather data logged from a weather station installed on the building itself, and comparing both simulation results. The paper then quantizes the impact of weather data’s accuracy on the total annual energy use by comparing both simulation runs.