SIMULTAN - Simultaneous planning environment for buildings in resilient, highly energy efficient and resource-efficient districts

This project enabled the opportunity for an essential energy efficiency increase within overlapping buildings, to achieve the objective of resilient cities and districts with respect to a high quality of life, resource sustainability and energy efficiency. The goal was a workable tool based on a multidisciplinary planning approach, to support the decision finding process in order to design both refurbishment projects and new developments within a highly efficient city.

Short Description

Starting point/Motivation

Studies show that there is significant potential for efficiency gain in energy systems encompassing not just a single building but entire building complexes. However, the expectations of building developers, operators and residents regarding performance (incl. energy cost, comfort, etc.) cannot be met. The difficulties in the planning and construction process and the unexpected effects on energy supply systems can generally be traced back to the lack of insight and understanding of complex resource and energy efficient systems and to communication problems among the involved stakeholders.

Contents and Objectives

Currently, there is a shortage of appropriate tools to support planers in the renovation of existing buildings or in the planning of new buildings. Such tools should enable the development of consistent scenarios encompassing both the energy supply system and the typical behaviour of energy end-consumers.

Energy suppliers on the other hand need tools that can take technological innovations in the building sector into account to determine a load and supply behaviour consistent with that of the end-consumers. The project aims to provide support for the optimisation of the planning process both of buildings and of energy supply networks within the context of the entire urban system.


The method for classification of energy end-consumer behaviour in an urban environment developed in the project Simultan determines the spatial distribution of typical behaviours by means of a survey and by subsequently aggregating the findings according to region, residential unit and net living space area. Significant parameters of the various behaviour types were evaluated and compared within their urban context. Subsequently, those parameters were analysed and their significance with regard to the "resident-sensitive" modelling of the energy end-consumer in urban areas was determined. This analysis provided the foundation for the definition of multiple development scenarios for the urban energy supply systems considering the potential of building technology.

The impact of the various tariff models on the total cost of heat supply for single residential buildings in three categories as well as the resulting designs of new tariff models were tested.

The requirement for support of an integral, simultaneous planning process of optimised building complexes resulted in the development of a tool for decision support on the level of a single building as well as on the level of a building complex. The design process was iterative and ran in cooperation with specialist planers in the areas of architecture, building physics and building services. This resulted in the design of data models and algorithms for comparative evaluation and analysis of technical measures for increasing the resiliency and efficiency of buildings while staying within the limits of pre-defined cost parameters. The interactive aspect of the planning process was tested within the context of several scenarios and optimized for efficiency and for compliance with the liability and warranty regulations.

One residential and one office building were the main use cases for evaluating the tool in regard to the design of a ventilation system, the display and editing of geometry, the placement of components, the calculation of various system parameters (e.g. U value, pressure loss, shading, thermal loads, etc.), as well as the translation to external data models.


The main result of the project Simultan is the development of a decision support system for simultaneous integrated multi-disciplinary planning of highly energy efficient building complexes, which can be utilised additionally as an analysis and fine-tuning tool for energy supply network planning.

The simulations on an urban level generated as part of the project were used as the basis for the design of multiple urban energy supply network development scenarios. These contributed to the improved understanding of the urban energy landscape and, consequently, to the development of new tariff models serving as additional motivation for finding efficient energy solutions in building development. Novel metrics for detecting malware in networks and a list of corresponding countermeasures were devised in the area of cyber security. The resulting complex informational landscape is presented in a web based information visualisation tool that incorporates multiple levels of detail – from a single building to an entire urban district.

Furthermore, a tool for interactive integrated planning was implemented. It uses the geometry as one of the main interfaces for information exchange between different components of the data model belonging to the various stakeholders. Neighbourhood relationships, aggregation, limited-by or contained-in relationships are thus automatically translated into data structures. The tool enables the definition of calculations based on component parameters, network topology, zone, building or building complex groups. Those can be based on elementary mathematical functions, graph evaluations within networks, or on complex web based simulations.

The tool uses its own data model. It is a linked hierarchical component collection – a component can have parameters, calculations and sub-components and an arbitrary number of other components can reference each component. The tool offers an upgradable translation service that enables the user to define a mapping between (parts of) this internal data model and (parts of) external data models of varying complexity. This facilitates the communication with external specialized tools. An interface to an individually configurable GIT server allows version control and support of project data managed by multiple stakeholders.

Prospects / Suggestions for future research

The tools developed in the context of the project Simultan have a multitude of interfaces. Their number can be further expanded by implementing current and future communication and data exchange standards – e.g. BIM. This should enable loss- and distortion-free information exchange with other tools, developed for various other aspects of the planning and management process.
Another open question is the timely detection and informative display of conflicts (e.g. several users working on the same wall) and the support of a real-time expert solution by providing appropriate procedures, visualisation and management methods. It is one of the most significant aspects of an efficient interactive planning tool.

There are two follow-up projects based on the knowledge gained in project Simultan – one in cooperation with Flughafen Wien Schwechat and a Smart City FFG project. As part of those, the interfaces to external tools and the usability of the Simultan tool are developed further.

Project Partners

Contact Address

Research Center of Building Physics and Sound Protection
Institute of Building Construction and Technology
Vienna University of Technology
Project leader Ao.Univ.Prof. Dipl.-Ing. Dr.techn. Thomas Bednar

Postal A.:
Karlsplatz 13/206/2
A-1040 Vienna

Adolf-Blamauer-Gasse 1-3/206/2
A-1030 Vienna

Tel.: +43 (1) 588 01 20 650