Urban Building Thermal Energy Analysis at City District Scale

This conference article presents the thermal energy analysis of a city district in Graz, Austria by the use of a newly developed numerical energy system model (see figure 1). From this model, a multi-tool workflow was derived to implement a high-resolution bottom-up approach at district scale. The goal was to carry out a sensitivity analysis regarding different boundary factors as varying parameters. The thermal energy demand (heating, cooling and hot water) as well as the CO2-equv. emissions of the existing building stock in the considered area were investigated.
The developed multi-tool workflow consists of several processing steps. 1) data input from stakeholders 2) pre-processing into a georeferenced 3D CAD urban building information model 3) import into central PostgreSQL data hub 4) automated urban building modelling 5) dynamic building energy simulation 6) post-processing and visualisation.
The thermal energy demand was calculated in hourly mean values for each building and each varied parameter. Using the annual total in combination with CO2 emission factors the annual CO2-equv. emissions were determined. The sensitivity of the stock area to the parameter variation regarding the annual thermal energy demand could be shown. Furthermore, the influence of different energy sources on the CO2-equv. emissions could be examined.