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Energy saving by tight air ducts

C+Duct. - The new generation of square air ducts with high saving potential for air handling systems

The challenge when it comes to sustainability

The air duct system in an air handling installation has an important function: Bring the air - conditioned with high energy input and conveyed by fans - to the locations where it is needed with the least amount of loss possible. If leakages occur in the air duct, the main flow rate needs to be increased to achieve the target volume flows for the rooms. The pressure loss of the parts increases by square of velocity. The energy need for air conveyance is proportional to the product from the pressure loss and volume flow. Consequently, the energy need increases with the third power of the volume flow increase. In other words: 10% loss due to leakage corresponds to an increase of the energy need for air conveyance by 33%. The leakage loss of common air handling systems often exceeds 20%. Apart from higher energy expenditures for the air conveyance, additional losses are caused by the fact that the conditioned air (heating, cooling, moistening) escapes unused at unexpected locations in the building.
Conclusion: The use of air duct parts ensuring a high extent of tightness offers a huge savings potential.

The starting situation:

With the standard air duct components that are mainly used today, the lowest requirement level (tightness class A) is reached when it comes to tightness.
Valuable primary energy is wasted as a result and the future user of the air handling system has to bear unnecessarily high energy costs due to the increased energy needs.

The solution:

With the C+Duct - the energy saving duct - BerlinerLuft provides a new generation of air duct components. What is unique, firstly, is the innovative manufacturing process where the flanged profiles are formed directly from the sheet metal strip. In contrast to conventional manufacturing processes, there is no need for an additional manufacturing and fixing of the flange connection. Critical seams between the flange and duct body associated with this can be omitted. Moreover, a sealant is injected in the duct's longitudinal folding. A special plastic component has been developed and ensures a reliable and neat sealing of the remaining corner notches.

The automated and industrial manufacturing processes for the C+ energy saving duct ensure, above all, a reproducible quality product apart from the increased capacity potential. In particular, the increased requirements regarding the tightness of parts according to EN1507 can be met very well with this technology.

To estimate the energy savings potentials resulting from the use of components from different tightness classes, an energy saving calculator is available in the form of the DUCTWIN software. (Free download at

The sustainable strengths:

The use of the C+Duct. energy saving duct can reduce the energy need in air handling systems by approx. 30%.

Further strengths:

  • Quality assurance by automated industrial manufacturing
  • Easier manufacturing process: No more frame production and no more hitting of frame profiles
  • Reduction of sealant consumption thanks to the formed flange connections and sealing of the fold notches (Pat. DE 10 2007 045 063 B4)

Moreover, the special sealing of the energy saving duct sustainably improves the hygienic properties of the ventilation system according to the requirements as per VDI 6022 and DIN EN 15780.

The inventors:

Dipl.-Ing. Diethard Niehoff
Product development of BerlinerLuft.
Komponenten und Systemtechnik GmbH
Niederlassung Mitte
01458 Ottendorf-Okrilla

Brief company profile:

Name: BerlinerLuft. Komponenten und Systemtechnik GmbH, a company of the BerlinerLuft. Group
Headquarters: 10365 Berlin-Lichtenberg
Year of foundation: 1928
Number of employees: 160
Solutions: Ventilation, air-conditioning, sound insulation, fire protection
Product range: Square and round duct systems, ventilation components and parts, louver dampers, butterfly valves and volume flow controllers, sound insulation systems, ventilation grills and air outlets, smoke removal and fire protection, ventilation towers and chimneys, welded special designs
Locations/international presence: Germany, Austria, Poland, Brazil, and Mexico