Effect of Heatwaves on the Cooling Demand of Austrian Residential Buildings

Sammanfattning: Buildings account for 40% of total energy consumption and 36% of CO2 emissions in the European Union. In 2019, households, or the residential sector, represented 26.3 % of final energy consumption in the EU out of which space cooling represented 0.4% energy consumption (Eurostat, 2021). In Austria, the residential sector represented 25.12 % of the final energy consumption in 2019. (IEA, 2020). Due to the effects of climate changes and changes in the insulation properties of the buildings over the years, the cooling demand in the residential buildings increases rapidly whenever the outdoor air temperature increases. Although cooling represents a very small share in the total energy consumption, still there is a huge potential in reduction of cooling demands of the residential buildings and meeting the cooling demand in future. This study is focused towards analyzing the effects of Heatwaves on the cooling demand of the Austrian residential buildings, specifically in multi-family houses of Vienna. Three different types of buildings are being analyzed that were constructed in Vienna in the 19th century i.e., Gründerzeit Era, 1960-1980 buildings, and buildings constructed after 2010. Five types of Heatwaves are analyzed based on intensity, severity, and duration of the heatwaves. The analysis involves simulating the building model in past Heatwave cases and simulated future climate conditions.The analysis showed that Extreme Heatwaves had the highest effect on the increase in the peak cooling demand followed by High radiation Heatwaves. The peak cooling load is always higher in older buildings irrespective of type and occurrence of heatwaves. The highest increase in the average cooling demand during a heatwave period was found to be for the older buildings during the prolonged heatwaves with an increase of 90 % as compared to usual climatic conditions case. The analysis on behavior of buildings during different heatwave cases showed that, the new buildings constructed after 2010 reacts quicker to the change in the outdoor temperature and resulting in attaining the maximum cooling demand around 1-2 hours earlier as compared to both the older buildings.