Future climate data for the building sector

By mid-Century the Swiss Climate Scenarios CH2018 project an additional warming of 2-3 degree Celsius in Switzerland if greenhouse emissions continue unabatedly. In consequence, heatwaves become longer, more intense and more frequent, whereas coldwaves will be less common. Changes in the outdoor climate also affect the indoor climate in buildings where people spend a substantial part of their day to work, study, and live. Buildings are designed to last for several decades with limited possibility to update heating and cooling systems. Hence, the climate a building will face during its lifetime has to be considered in the planning process. In general, it can be expected that the heating demand will decrease whereas the cooling demand will increase in the near future. However, a holistic and quantitative assessment of the effect of climate change on the energy demand in buildings is still missing. For the use in building simulations, climate data at hourly resolution with physical consistency for a number of key variables such as temperature, humidity and radiation are required. To ensure that the use of the data is feasible in practice, the climate of the future needs to be condensed into a single year, representing typical mean conditions as well as typical deviations from the mean. In addition to the typical year, the assessment of an extreme year can provide information on the level of comfort during a once in a lifetime event and the performance at maximum capacity of the installations. Users of this data are practitioners in the building sector as well as officials from federal offices.

Our project aims to provide future climate data for the building sector at station level. For this, we make use of observations as well as climate change information from the Swiss climate scenarios CH2018.  Together with the users, we define criteria that shall be represented by the future typical and extreme years. We design different methods to create this years based on observations and scenarios and under consideration of existing standards and regulations. The methods are compared in a climatological assessment and sensitivities to emission scenario and time horizon are explored using building simulations. The results of this project support decision-making to optimize national and international norms and regulations and to design adaptation measures. The climate data will be made available to practitioners who can use them to plan the buildings of the future.