New hexagonal counterflow recuperators offered by VTS


The HEX module has been designed for:

  • WS021c-WS150c compact air handling units, as their integral component,
  • VVS021-VVS150 modular air handling units, as a heat recovery section replacing the hexagonal exchangers (in AHUs sized VVS021 to VVS040), and Premium Plus cross-flow exchangers (in all other AHUs) used previously.

The solution will be available with aluminum (AL) and HIPS (high impact polystyrene) exchangers, just as it is the case in suspended air handling units.

The AL version will be launched first, followed by HIPS.


The newly designed HEX module is characterized by high heat recovery efficiency and low air stream resistance, which significantly improves the competitiveness of the VTS offer.

The design of the HEX module guarantees a high degree of airtightness between supply and exhaust paths. Thanks to that the solution suitable for ventilating rooms requiring separation of air supply and exhaust streams, including rooms with strict hygienic requirements.


The HEX module is available in the cross-flow counterflow configuration with a bottom-mounted supply air outlet.

With its fan sections installed, the HEX module serves as the unit base of the compact air handling unit that may be optionally expanded by additional functional modules (heaters, coolers, etc.). All elements of the compact air handling unit are encased within sandwich panels comprising two layers of sheet metal with inner lining made of mineral wool. The complete product, together with the selection program, is certified by Eurovent .

The compact units offer two options for positioning the fan relative to the hexagonal exchanger (see the figure below):

Layout 1 - Supply and exhaust fans installed on the opposite sides of the HEX exchanger. This configuration is only available for air handling units without a mixing box.

Layout 2 - Supply and exhaust fans installed on the same side of the HEX exchanger. This configuration is available for air handling units with and without an air mixing box.

The HEX module is a system comprising interconnected segments of hexagonal counterflow exchangers, an integrated by-pass damper and air dampers guaranteeing that air flows through each segment in an evenly distributed manner. To minimize the length of HEX modules, different internal positions of exchangers are relied upon, depending on the size of the air handling unit.


Combined with the special design of the fan units and the ultra-short Mini-Pleat filters, such an approach has resulted in the shortest compact air handling unit available on the market. Compared to the modular AHU with the PREMIUM PLUS cross-flow exchanger, the compact AHU with the HEX module is by over 50% shorter.

Despite its small size, the compact air handling unit with the HEX module may be used in buildings with different functional requirements. Functional diversity is achieved by enclosing optional functional modules (eg heater, cooler or additional air filters) in a separate casing. A common control system integrated with the air handling unit guarantees full control over all functionalities.

An intuitive mobile device interface with visualization capability makes the operation and monitoring of the unit an effortless task and includes a remote online control functionality.


Compact air handling units are delivered as Plug & Play units, with factory-installed controls solutions, and are ready for immediate operation after connecting power and peripherals.

The controller is installed inside the unit, and the junction box is either flush-mounted on the top surface of the AHU or is installed externally, on the back of the unit.

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