The shape of days to come: Effects of climate change on low energy buildings

Abstract

Upcoming climate change effects will vary with region, season and time of the day. Existing annual and daily temperature cycles will shift and be reshaped, leading to increased air temperatures earlier and later in the year. Buildings will be affected by these changes, especially the ones using passive design strategies, whose performance is highly weather dependent. This study analyses the shift and reshape of annual and daily temperature cycles, focusing on when, where, and how passive design strategies (natural ventilation (NV), night cooling, and solar shading) are affected, going beyond season or yearly effectiveness. High temporal resolution (sub-daily and monthly) modelled data for the time frames (1971–2000) and (2017–2100) have been used to analyze upcoming changes in temperature, their interaction with solar radiation, and the consequent impacts on passive building strategies efficiency in European Union 43 most populated cities.The results show that changes in the diurnal temperature cycle will affect the daily temperature range (DTR), leading to two daily temperature cycle shapes: daytime (DTR increase) and a nighttime (DTR decrease), with different impacts on the heating and cooling seasons. Further, mild and warm days will occur earlier and persist until later in the year, shifting NV and shading seasons. In Northern Europe, NV season will be 6 weeks longer, while in Southern Europe it will be 9 weeks shorter. In Southern Europe, shading season will increase 2.5 months, direct solar radiation in south façades will increase 35% consequence of −13.5° in average maximum solar altitude, making overhangs less effective.