Climate change impacts on building heating and cooling energy demand in Switzerland

The potential impacts of climate change on heating and cooling energy demand were investigated by means of transient building energy simulations and hourly weather data scenarios for the Zurich-Kloten location, which is representative for the climatic situation in the Swiss Central Plateau. A multistory building with varying thermal insulation levels and internal heat gains, and a fixed window area fraction of 30% was considered. For the time horizon 2050-2100, a climatic warm reference year scenario was used that foresees a 4.4 °C rise in mean annual air temperature relative to the 1961-1990 climatological normals and is thereby roughly in line with the climate change predictions made by the Intergovernmental Panel on Climate Change (IPCC). The calculation results show a 33-44% decrease in the annual heating energy demand for Swiss residential buildings for the period 2050-2100. The annual cooling energy demand for office buildings with internal heat gains of 20-30 W/m2 will increase by 223-1050% while the heating energy demand will fall by 36-58%. A shortening of the heating season by up to 53 days can be observed. The study shows that efficient solar protection and night ventilation strategies capable of keeping indoor air temperatures within an acceptable comfort range and obviating the need for cooling plant are set to become a crucial building design issue.