Pulsed Air Supply
Use of pulsated supply air jets to increase ventilation efficiency and thermal comfort and to reduce primary energy requirements
Duration: 2,5 years
- TU Berlin, Hermann-Rietschel-Institut
promoter: Forschungsvereinigung für Luft- und Trocknungstechnik (FLT) e.V.
Sponsor: BMWi - Bundesministerium für Wirtschaft und Technologie
IGF-project: 20399 N
People in industrialised countries often spend more than 18 h/day indoors. Mechanical ventilation systems are increasingly being used for the removal of material and thermal loads in the course of the tightness requirements according to the current EnEV 2014. The selection and placement of air diffusers, as well as the design of the supply air volume flow rate and the supply air temperature, depend on the maximum room occupancy. If the room is not fully occupied, the supply air volume flow can be reduced while the temperature difference between room air and supply air remains the same. This would lead to a changed and possibly uncomfortable room air flow. For this reason, the supply air temperature must be raised and the volume flow must remain virtually unchanged in order to maintain the mixed ventilation principle. This operating condition can lead to an unnecessarily increased consumption of auxiliary energy (fan power). At partial load, the use of pulsated supply air jets offers a correspondingly increased potential.
The project will lay the foundations for the design of transient air distribution systems. Questions regarding the assessment of thermal comfort will be answered and new approaches to the fluidic design of ventilation systems will be developed with the aid of jet laws. The energy saving potential of the auxiliary energy demand is determined, which can be taken into account in the evaluation of this procedure in the planning.
In the case of transient ventilation systems, the influencing factors and effects in the room are manifold and therefore difficult to predict. It is therefore very difficult for building owners, investors, architects and specialist planners to estimate the economic benefit compared to the unknown effects. However, this is an important prerequisite for a new technology to be able to assert itself on the market. In this research project, the room air flows generated by dynamically operated ventilation systems are for the first time placed on a scientifically sound and physically describable basis. The evaluation models to be developed for comfort, ventilation effectiveness and energy expenditure contribute to planning and lay the foundation for practical use. Therefore the economic chances of success after project end are to be classified as high.