Optimization of urban design/retrofit scenarios using a computationally light standalone urban energy/climate model (SUECM) forced by ERA5 data

Standalone urban canopy models attempt to replace the full-fledged atmospheric representation with a simplified equivalent. In this study, we investigate the offline forcing of an offline Standalone Urban Energy/Climate Model (SUECM) by the fifth generation reanalysis data from the European Centre for Medium-Range Weather Forecasts (ERA5). The result is a computationally light numerical model of the urban canopy air that can be incorporated in a design optimization work flow. The model is applied to the city of Abu Dhabi (United Arab Emirates). The model’s accuracy is validated against measurements. The urban heat island (UHI) mitigation and building energy conservation potential of several urban design/retrofit scenarios is evaluated in comparison to business-as-usual. District cooling implementation is best overall with an estimated reduction of cooling electricity demand by more than 40% and of UHI intensity by more than 25%. Building-integrated vegetation systems (green roof/wall) are also effective mitigation/conservation measures; however, their positive impact must be weighed against the need for irrigation. Among the two other design/retrofit scenarios, cool surfaces are more effective in reducing UHI (-16%) while energy efficient buildings are to be preferred in case cooling energy demand reduction is prioritized (-25%). Based on the physical network representation principle, the model has been implemented in a graphical development and simulation environment, thereby simplifying specializations and future enhancements.