DWDI incorporable forward-curved — high-airflow double-inlet centrifugal for AHU units

DWDI incorporable fans with forward-curved impeller are complete centrifugal units — double-inlet rotor with their own spiral casing — designed for integration as the heart of medium-to-large air handling units (AHUs). Unlike Plug fans that operate without their own casing in the AHU plenum, DWDI incorporable units come with an integrated spiral casing and bilateral inlet — a more complex solution but with superior airflow performance at the same motor footprint.

DWDI — Double Width Double Inlet — in practice: the centrifugal rotor draws air simultaneously through two inlets, one on each side of the casing (left and right). Total admission area is effectively double that of a single-inlet rotor of the same diameter. The direct result: at the same motor power and rotor diameter, a DWDI delivers 30–50% more airflow than an equivalent single-inlet fan — or conversely, it can deliver the same airflow with a smaller, quieter motor.

Forward-curved blades and their relevance in AHU design: forward-curved blades generate the highest airflow at the lowest speed of all centrifugal configurations. For AHU manufacturers, this means they can cover high airflows with a fan running at relatively low speeds — a direct advantage in reducing noise levels transmitted through ducts to building occupants. This characteristic makes them preferable in AHUs for hotels, hospitals and offices where acoustic performance is a design constraint.

The integrated EC motor with driver plug and play mounted directly on the casing accepts 0-10V or Modbus signal for AHU automation integration. The complete system is IP54. Rotor is dynamically balanced to DIN ISO 21940-11.

AHU integration and installation: the DWDI incorporable scroll casing is fixed directly to the internal structure of the AHU unit or to the central frame of the air handling plant. The bilateral inlet connections and single discharge connection simplify air distribution — air enters from both sides of the unit and exits through a single discharge outlet directed towards the filter or thermal treatment section.

AHU types where this is the standard component: residential and commercial ventilation plants 1,500–20,000 m³/h, AHUs for hotels (room ventilation, corridors, common areas), plants for medium and large office buildings, commercial space ventilation systems, large fan coil units for common areas.

Selection: check required airflow and total AHU static pressure at the desired duty point. Forward-curved blades have a relatively flat Q-p characteristic — tolerant of hydraulic resistance variations, but sensitive to motor overload at high airflows (non-self-limiting power characteristic). If the AHU operates with a variable frequency drive, consult us for confirmation.

👉 Plug backward curved incorporable EC — single inlet without casing, minimum footprint 👉 DWDI backward curved incorporable EC — double inlet, maximum efficiency and self-limiting