The research project investigated whether decentralised ventilators (dVt) can reduce the energy demand of mechanical ventilation systems compared with conventional volume‑flow‑regulators (VSR). In a typical centralised system a single fan creates a pressure drop that is then attenuated by VSRs to distribute the required airflow to individual rooms or zones. This attenuation is energetically inefficient because the fan must overcome the additional pressure losses. The dVt concept replaces the VSRs by placing small, decentralised fans at the point of use. Each fan generates the necessary pressure locally, eliminating the need for pressure‑drop attenuation and thereby lowering the overall fan power.

The study examined several regulation schemes. For single‑room control the system can operate with or without direct volumetric‑flow measurement; the latter relies on pressure‑rise measurements at each fan. A third variant introduces an over‑ventilation strategy that supplies a higher airflow than strictly required, which can improve indoor air quality at the cost of additional fan power. For group‑room supply two configurations were analysed: a “worst‑room” strategy that prioritises the room with the highest demand, and a mixed‑concentration strategy that balances the supply across the group. In all cases the decentralised fans were equipped with CO₂ sensors to enable demand‑based control.

Experimental validation involved measuring 24‑hour ventilation profiles, determining the standard measurement uncertainty of volumetric‑flow sensors, and validating a pressure‑loss model for the ductwork. The results showed that the decentralised system achieved a reduction in total pressure loss of up to 30 % compared with the VSR baseline, translating into a 10–15 % decrease in fan power for typical office and classroom loads. Volume‑flow differences between rooms were reduced to less than 5 % of the nominal flow, indicating improved balance across the building.

An economic sensitivity analysis was performed for three representative use cases: a small group office, a classroom, and a lecture hall. Investment costs for the dVt system were varied between 70 % and 130 % of the baseline, usage duration between 12 and 18 years, and electricity price increases of 3.8 % per year. The analysis revealed that the group‑office scenario is relatively insensitive to these variations, with a net present value change of only ±5 % across the parameter space. In contrast, the lecture‑hall scenario exhibited a higher sensitivity, with net present value changes up to ±30 % when investment costs and electricity price assumptions were altered. The classroom lay in between, showing moderate sensitivity. Overall, the dVt system proved economically attractive for most typical building types, especially when the investment cost is kept within 80–120 % of the baseline and the expected electricity price rise is moderate.

The project was carried out at the University of Kassel, where the research team developed the system concepts, performed the measurements, and conducted the economic modelling. While the specific industrial partners and funding source are not detailed in the provided excerpt, the work was integrated into the university’s teaching and training programmes, indicating close collaboration between academia and industry. The study demonstrates that decentralised ventilation can deliver measurable energy savings and improved airflow balance, offering a viable alternative to conventional VSR‑based systems for modern, energy‑efficient buildings.