Influence of weather data morphing in urban building simulation. A case study

One issue related with dynamic energy simulation of buildings is the need to use accurate weather data to perform reliable analyses. In particular, available weather data often refer to rural sites (e.g. airports), and as such they are not suitable for the simulation of buildings located in urban areas. Amongst the tools available to provide specific weather data for urban sites, the Urban Weather Generator (UWG) has recently raised increasing attention. This tool estimates the local hourly air temperature and humidity in urban contexts starting from weather data coming from a rural weather station nearby, and accounting for the Urban Heat Island (UHI) effect due to buildings and various anthropogenic heat sources within the urban settlement. The aim of this paper is to discuss the uncertainty that the choice of the weather dataset introduces in the outcomes of dynamic energy simulations for buildings located in urban areas. To this aim, different weather datasets are considered, corresponding to: i) the weather file available in the EnergyPlus database for the airport of Catania (Southern Italy), ii) its UWG morphed version, iii) a more recent weather dataset released by the Italian Thermo-Technic Committee (CTI) and iv) its morphed version. The paper comments on the differences amongst these data, along with their impact on the calculation of the heating and cooling load for a representative multi-storey apartment block.