Assessing Wintertime Energy Consumption for Urban Heating in an Alpine City

The assessment of energy consumption of the built environment is an essential prerequisite for the implementation of policies aiming at reducing the energy demand of buildings, also in view of the estimated expansion of urban areas worldwide. However, many studies focus on summertime cooling consumption of buildings, whereas limited attention has been paid so far to heating consumption during wintertime. This work aims at assessing the urban heating needs of the city of Bolzano, in the Italian Alps, simulating buildings heating consumption by means of the Weather Research and Forecasting (WRF) model coupled to a multilayer building energy scheme (BEP+BEM). High-resolution simulations are performed for a typical wintertime period and results are compared with estimates of the actual energy consumption of the whole urban area. Energy consumption estimates are obtained on the basis of a detailed description of the building types in the urban area, including their function and occupancy period, and from measured values of the total annual consumption and of the load curves representative of various building categories. It is found that the model can reproduce with good accuracy the heating consumption in the residential area, including its timing and spatial distribution. On the other hand, some problems are found in the commercial-industrial area, where different buildings display peaks of energy demand, that the model cannot reproduce. Finally, the simulated energy consumption is correlated with the spatial distribution of different urban canopy parameters, to evaluate the impact of urban morphology on building heating demand.