Climate change and the urban heat effect are expected to have a large influence on the energy consumption and thermal comfort of buildings. However, using meteorological data which incorporates effects of climate change and characteristics of cities is not currently a standard practice in building simulation.
By default, Typical Meteorological Years (TMY) based on 20-year meteorological statistics from nearby meteorological stations often outside cities are used. This may lead to important discrepancies between simulation results and actual energy consumption and/or indoor climate data for buildings in urban areas.
These effects are analyzed within Building energy part of H2020 climate-fit.city project. First, adapted urban and future meteorological data modelled using the VITO UrbClim model and standard meteorological data were compared. Second, these data were included within the Meteonorm software (version 7.3.1). This was carried out for current climates (based on ERA-Interim) as well as for future scenarios (RCP 4.5 and 8.5 for 2046-55 based on Euro-Cordex) for the cities of Barcelona, Bern, Prague, Rome and Vienna. More cities will follow. Like this Meteonorm includes a combination of urban and future climates accessible in a user friendly tool.
In a third step the urbanized TMY data sets generated by Meteonorm were used to simulate energy consumption, peak loads and indoor climate conditions with models of several typical buildings. The building simulation tool IDA-ICE was used in this study. In this comparison we show a simulation for a multi-family house (old and new standards) for current and future climates. The whole-year simulation runs were compared to the reference scenario – the standard TMY (available in Bern and Vienna).
Results show that meteorological data are modelled generally well; however at some sites differences are statistically significant. For current climates heating energy consumption is 10-25% lower within cities and cooling energy up to 60% higher (Barcelona). Even bigger changes are seen for future climates: Heating loads are reduced by up to 30% and cooling loads are higher by more than 100% (they are 2-3 times higher than heating loads in Barcelona by 2050).
Also peak loads will differ significantly in future, which will affect electricity load curves. Interestingly the differences regarding RCP scenarios aren't big for 2050 for Barcelona. For both RCP 4.5 and 8.5 in winter the peak load is reduced by 20% and in summer enhanced by 50% for existing buildings.