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SimStadt - energy simulation of urban districts

SimStadt, Energy simulation of urban districts

EnEff:Stadt - Forschung für die energieeffiziente Stadt

Visualisation of the heating requirement of the district of Ludwigsburg-Grünbühl, which is in need of rehabilitation.

© zafh.net

Technology summary

Software type Planning, Analysis, Balancing/Optimising
Term of project Dezember 2012 - Dezember 2015
Identification code SimStadt
Available from

www.simstadt.eu/en/index.html

Key aspects

Project description

Initial situation

Modelling the cooling, heating, and electricity demand is a prerequisite for planning, optimising operations, and scenario calculations of innovative urban energy and building concepts with grid expansion strategies. Both issues have barely been investigated on an entire city or district level, since existing building energy performance simulation methods were developed for a more detailed analysis of individual buildings without considering the influence of urban morphology. Due to the rapid development of information and communication technology, and the progress made in (semi-)automatic data acquisition, it has become possible to record urban geodata in three dimensions. Virtual 3D city models are increasingly being employed to solve spatial tasks in the fields of urban and regional planning, and the environment and energy, amongst others. An increasing number of cities are using virtual 3D city models for analysis and visualisation purposes.

In almost all cases, the software systems for heating requirement simulations are based on demand analyses of individual buildings. The geometry data required for building simulations are now usually acquired via building surveying methods, or floor plans and layouts. An extrapolation of the simulated individual buildings to the residential area or urban district level is very complicated. Urban microclimate is almost never considered in building simulation models. The distribution of external irradiance, and resulting solar yields, are strongly affected by mutual shading and multiple reflections. Furthermore, the distribution of external pressure acting on buildings is usually not available for a calculation of natural ventilation in building simulation models, nor are heat island effects in sealed urban areas. The prototype model CitySim (University of Nottingham) offers promising approaches that are being employed in the project.

The calculation model of “Heating atlas Baden-Württemberg” is a static model in which, for example, user behaviour is not considered. In the EU project named POLYCITY5, coordinated by the University of Applied Sciences Stuttgart, a method for calculating the heating requirement of residential buildings and estates has been developed, which takes into account this user factor. The relevant values were validated using consumption values as measured in the test region (Ostfildern, Scharnhauser Park), and they show a good agreement with the total heating requirement on the residential estate level with less than 5 % deviation from actual consumption.

Project, objectives

Since 2013, a virtual 3D model with geometric and semantic data can image cities and their structures throughout Germany – with a high application potential, particularly in the fields of urban planning, the environment and energy. Nationwide 3D city models are currently being compiled as part of ordnance survey activities. They are an essential source of data for building envelopes. Development and testing this new simulation environment is underway in the homonymous research project from December 2012 through to December 2015. The aim of the project is the utilisation of 3D city models for energy simulation purposes. The heating requirement simulation modules developed in this project were tested in several urban districts, and were validated by comparing them with consumption data.

Next steps

In 2014, the software interface and the data library of the simulation environment will be implemented; a first beta version will be usable by the end of the year.
Once the product is market-ready, it will enable a wide range of applications: from heating requirement diagnoses, and photovoltaic potential studies to the simulation of building restoration, and renewable energy supply scenarios. This also includes energy analyses of urban districts, cities, and even regions.

Project partners

The development team includes the Centre for Sustainable Energy and the Centre for Geodesy and Applied Informatics of the University of Applied Sciences Stuttgart, the IT company M.O.S.S. Computer Grafik Systeme GmbH and GEF Ingenieur AG.

  • Lecture on “CityGML-based 3D City Model for Energy Diagnostics and Urban Energy Policy Support“; excerpt of the proceedings of BS2013 on “CityGML”