Externally funded project

Decentral fans for air transportation in central HVAC systems (dezentrales Ventilatoren (dVt)-System)

Project Details
Project duration: 10/201307/2018


The department of technical building equipment of the
University Kassel investigated in cooperation with Fraunhofer IEE (früher IBP), ebm-papst and
innovaTec whether the electrical energy consumption for air
transport can be reduced by replacing variable air volume dampers of HVAC
systems with decentralized fans. These decentralized fans build up the exact amount
of pressure differences needed at the designated locations required for air
ventilation. Thus, inefficient throttling is avoidable. The innovative air
conditioning concept is called semi-central or decentral (dVt) System. The research project analyzed

  • implementation potentials, energy savings and profitability on a
    theoretical level
  • the concrete operational performance under laboratory conditions at a
    test stand and
  • the operational performance in real operation inside an office building
    (application test)
The theoretical analyses show that the semi-central ventilation via the
dVt-system lead to an energy saving of 10% to 50% compared to the conventional
system using variable air volume dampers and a constant admission pressure (VSR
system). The energy savings depend essentially on the use of the supplied area.
Favourable and thus recommendable for the semi central ventilation are nominal
volume flows of the decentralized fans of more than 250 m³/h, otherwise the fan
efficiency levels will drop too low. In addition, the ventilated areas should
have frequent and significant partial load situations, such as in auditoriums,
seminar rooms, laboratories, theatres, cinemas. Under these conditions,
semi-central ventilation with the dVt-system is economical in most cases.

In the research project, detailed plant-related implementations of the
dVt system were analysed. Four design variants can be implemented by just using
components currently available on the market. These variants can be used to set
up the ventilation system of a complete building.

The theoretically determined energy savings are confirmed by first
practical experience in the application test of the dVt system in the ZUB
building (offices, lecture hall). The measured energy savings are between 25%
and 30%. Semi central ventilation via the dVt system is an interesting approach
to increase the energy efficiency of air conditioning systems with
demand-dependent volumetric flow adaptation.

Electrical Energy Consumption, Energie Efficiency, Fan, HVAC, Klimaanlagen, Lüftungsanlagen, RLT-Anlagen, Stromverbrauch, Ventilationsystem, Ventilator

Principal Investigator



Last updated on 2020-26-08 at 09:21