The department works on the following research topics:

Energy

• Monitoring and performance analysis of buildings (benchmarking, energetic operation optimization, monitoring software)
• Integral building and energy concepts, simulation-based system optimization (operation, load management, grid interaction)

Indoor quality of stay

• User satisfaction at workplaces (surveys, comfort indices, certification)
• Comfort (thermal, visual) and user behaviour under transient conditions (summer)

Test subjects in the "Lobster" climate test stand

MSc. Romina Rissetto, PD Dr. Marcel Schweiker, Prof. Andreas Wagner

Duration: July 2018 until September 2021

The starting point is the challenge of ensuring an acceptable summer indoor climate without active cooling and air conditioning in the context of ambitious renovation measures. The overarching goal of this collaborative project is the development and first demonstration of an innovative technology to increase air movement in workplaces to increase user satisfaction and support night ventilation. Comfort surveys of the employees of the District Office Dillingen: characteristic values for the effect of the ceiling-integrated fans to be developed on user satisfaction and the behaviour resulting from the installation will be analysed and incorporated into comfort and user behaviour models. The data collected in this way enables an evaluation of user comfort before and after the refurbishment or with and without ceiling-integrated fans. The employees of the district were surveyed in the summer of 2018 before the renovation of the existing building. Overall, the evaluation in the district office was predominantly negative in the summer survey. On average, respondents were nearly dissatisfied in most satisfaction categories (Schakib-Ekbatan, 2015), especially with temperature conditions. User acceptance studies: to validate the effect on user satisfaction, user acceptance studies are conducted with volunteers in the indoor climate testbed LOBSTER at KIT. The results show that there is a significant difference in acceptance and comfort rating of thermal conditions between the configurations with and without ceiling integrated fans. The influence of the temperature (28°C vs 31°C) on the perception of the indoor temperature is more significant than the control of the fan (fixed vs adjustable air speed) and the direction of the air (different positions of the subject in the office with respect to the position of the fan).

Funding: funding amount 300.276€ (share fbta); German Federal Ministry for Economic Affairs and Energy - PtJ.

Partner:

• Karlsruhe Institute of Technology (KIT)
• Institute for Design and Building Technology
• Department of Building Physics and Technical Finishing
• District of Dillingen a. d. Donau
• University of Wuppertal (BUW)
• Industrial partner

Further information: https://fbta.ieb.kit.edu/182_931.php

Dr. Reza Safi Zadeh, Prof. Andreas Wagner

Duration: June 2016 until December 2020

Radiant heating systems are an interesting option in the context of heating system refurbishment, if radiant temperature asymmetry and local discomfort due to low indoor surface temperatures can be avoided. In this project, the potential of low-temperature (28-38 °C) radiant ceiling heaters was investigated based on subjective experiments and general thermal comfort criteria. The experiments were conducted in the LOBSTER test rig at KIT. The results show that a radiant ceiling heating system operating at a low temperature level can largely ensure neutral thermal sensations and satisfactory comfort for the majority of all body parts when the building envelope meets an increased building energy efficiency standard. Contrary to expectations, the head was found to be the most comfortable body part, even though it was closest to the warm ceiling and it is the most sensitive to warm conditions. Participants still rated most of their body parts as 'neutral' at a relatively high radiation temperature asymmetry; therefore, a radiation temperature asymmetry of 7.5 K is suggested as a 10% dissatisfaction threshold when users are wearing winter clothing and the operative temperature is in the range of neutral conditions. The chosen boundary conditions in the experiments represent quite extreme conditions; in reality the comfort ratings would be more positive and therefore radiant ceiling heating represents an interesting option for building renovation. The project is funded by the German Federal Ministry for Economic Affairs and Energy.

Partners: Institute for Sustainable Technical Systems, Albert Ludwigs University Freiburg (project management) Department of Fluid Machinery, KIT Fraunhofer Institute for Solar Energy Systems, Freiburg various industrial partners Funding: funding amount 739,000 € (share fbta); Federal Ministry for Economic Affairs and Energy.

Further information:

http://fbta.arch.kit.eduhttps://www.lowex-bestand.de/?lang=de

Duration: 01 June 2016 to 31 December 2020

Heat pump technologies will play an increasingly important role in the heat supply of existing buildings in order to realise the climate policy goals for heat supply. In this project network, electric and gas heat pumps are therefore being further developed and demonstrated for energy-efficient refurbished existing buildings and their economic efficiency increased. At the fbta, a building matrix was developed as part of the project, which represents the stock of multi-family buildings with its characteristics. For this purpose, existing data and statistical surveys were collected on the basis of characteristic features such as building and apartment sizes, number of occupants, quality of the building envelope or building technology and sorted into the matrix according to building age and size. On this basis, project-relevant refurbishment scenarios are determined and bundles of measures are defined for further investigation. Furthermore, it is analysed how modernisations of multi-family buildings are carried out in reality, which actors are involved and which decisions are made when and by whom. In expert interviews, the logics of action when making relevant decisions and the influence of non-technical factors on the modernisation process and on the use of new technologies will be recorded. The results report will be used to enable process redesigns for the successful deployment of new technologies and LowEx systems.

Partners: Institute for Sustainable Technical Systems, Albert Ludwigs University Freiburg (project management) Department of Fluid Machinery, KIT Fraunhofer Institute for Solar Energy Systems, Freiburg various industrial partnersFunding amount
:
Funding amount
739,000 € (fbta share)
Sponsor: German Federal Ministry for Economic Affairs and Energy

Further information:
http://fbta.arch.kit.edu
www.lowex-bestand.de