Urban Building Energy Modeling for Retrofit Scenarios : Development, Calibration, Validation and Implementation for Swedish Residential Buildings

Abstract: The necessity for an accelerated transition of urban energy systems and, in particular, the building sector toward energy efficiency and carbon neutrality poses new challenges to planning and retrofitting existing buildings. To cope with these challenges, so-called urban building energy models (UBEMs) have been introduced for quantifying the energy demand in the building sector, identifying the hot spots of energy use and suggesting scenarios for retrofitting the buildings. Methods for developing an UBEM vary. In this thesis, based on a comprehensive review of the state of the art, an approach to the development of an automated simplified UBEM using open-access data from Swedish residential buildings was taken. The developed model makes use of building-level geo-referenced energy performance certificate (EPC) data to automatically form simplified single-zone models of buildings which are one-by-one simulated by the building energy simulation software EnergyPlus. The UBEM also includes energy retrofit scenarios for improving the energy efficiency of energy-intensive buildings based on the latest Swedish building codes, the Passive House standards as well as net zero energy buildings.The choice of simulation software and modeling complexity was made based on the results of this thesis proving that EnergyPlus was the most suitable software for handling large-scale building energy models efficiently. The results also showed that the mean absolute percentage error (MAPE) of a simplified single-zone model from a detailed multi-zone model is only 6 %. This error becomes marginal when the spatial aggregation of the results increases. With the calibration of the model using the EPCs, the accuracy of the model improved considerably. The MAPE of the simulated annual energy demand from the actual energy performance of the buildings was reduced from 78 % to 26 %, for the case study city of Borlänge. The validation of the model for independent sources of hourly, and monthly energy measurement data as well as EPCs proved the reliability and applicability of the model for being used for other cities or other temporal resolutions than those that it was calibrated for. Implementation of the UBEM and the energy retrofit scenarios in the city of Varberg, Sweden, resulted in improved energy efficiency of the city, i.e., the residential building sector, to the extent that the minimum requirements for net zero energy were met for several city districts.