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Grid-reactive buildings

Joint “Grid-reactive buildings” project: Holistic evaluation of construction physics and building energy systems, including their role in the energy industry: energy, exergy, power input and output.

EnEff:Stadt - Forschung für die energieeffiziente Stadt

Schematic illustration of a demand-optimised urban district with a depiction of the different requirements and generation units based on renewable energy sources.

© Fraunhofer IBP, Energiesysteme

Technology summary

Software type Analysis, Balancing/Optimising
Term of project Juli 2012 - Juni 2016
Key aspects

Project description


The joint "grid-reactive buildings" project is aimed at viewing buildings holistically as part of the energy system, whereby primary energy, exergy and energy industry aspects shall be investigated and combined. The project is also focussing on how buildings and building groups will behave in a future intelligent electricity network and how they can contribute to the grid stability. In conclusion, a proposal shall be developed for a consistent evaluation methodology. For this purpose, proposals derived from the knowledge gained will be examined as to how they can be implemented in existing standards and ordinances. This is intended to enable planners and decision-makers to evaluate individual buildings and large building groups in energy, exergy and energy industry terms.


In order to achieve this goal, the joint project is focussing on the following core aspects:

  • Low-exergy supply concepts
  • Energy industry-based evaluation of technology scenarios
  • Evaluation methodology for grid-reactive buildings.

For this purpose a holistic evaluation methodology shall be developed for buildings as part of the energy system that enables a comparative analysis and assessment to be made of energy concepts for buildings in primary energy, exergy and energy industry terms. Five evaluation levels will be taken into account: components, systems, buildings, urban districts and cities.

Based on the developed evaluation methodology, a suitable and simplified balancing process will be available for DIN V 18599 that takes in account both the integration of so-called “LowEx” components and technologies as well as energy and exergy evaluations.

The dynamic modelling of the building sector in Germany and its energy procurement therefore enables the integration and evaluation of buildings at the urban district and city level in regards to energy industry aspects. This makes it possible to test different technology scenarios and solutions, particularly given the uncertainty about the actual development of the energy system.

Project partners

Three different partners are involved in the project:
The Thermal Systems and Buildings department at the Fraunhofer Institute for Solar Energy Systems (ISE) is responsible for coordinating the project, the cross-sectional analysis of selected building concepts in energy and energy industry terms and with implementing the results in the EnOB building database.

The Energy Systems department at the Fraunhofer Institute for Building Physics (IBP) is focussing on developing a consistent and stationary exergy evaluation methodology for buildings, integrating so-called “LowEx” system concepts and exergy characteristic values in German Energy Saving Ordinance (EnEV) evaluations, and on producing dynamic simulation models. In addition, Fraunhofer IBP is responsible for the knowledge transfer and conducting national and international workshops.
The E.ON Energy Research Centre at RWTH Aachen is in charge of building a hardware-in-the-loop test rig for investigating different energy supply systems, simulating the grid and developing parameters for the grid compatibility.
The project partners are working together on developing both an overall simulation model for an urban district as well as a consistent and dynamic exergy-based evaluation methodology for local authorities.

Next steps

The initial aim is to carry out an energy-related, cross-sectional analysis of selected building concepts by the end of 2013 based on long-standing measurement campaigns from, among others, EnOB, EnSan, LowEx:Monitor and ModBen, whereby the interactions between the buildings and supply technology will be characterised.

Based on this, energy-, exergy- and energy industry-related partial energy characteristic values will be determined automatically for 10+ exemplary buildings and a comparison and assessment of the overall concepts carried out. In conclusion, a proposal will be developed for integrating partial energy and exergy characteristic values in the EnEV evaluation.

  • Final report on IEA ECBCS Annex 49, which is obtainable from the Fraunhofer Verlag publishing house