Frenger's Active Chilled Beam "Turn Down" Functionality

Chilled Beam Render

Pioneering ahead of other competing Chilled Beam manufacturers, all of Frenger's Active Chilled Beams feature a "Turn Down Facility" as standard. This unique functionality allows Frenger's Active Chilled Beams to operate at significantly reduced air volumes whilst still creating a full Coanda Effect and good waterside cooling effect even at Air Pressures as low as 15Pa (pascals).

Frenger® are able to achieve full Coanda and induction of room air even at reduced static pressures as low as 15Pa due to Frenger's Patented ‘Burst Nozzle Technology’, which is featured as standard on all of their Active Chilled Beams, and also helps to reduce noise levels and encourage greater levels of induction.

Frenger's Turn Down facility allows room spaces to have lowered fresh air supply volume by simply reducing the pressure, such as when the room is at lower than designed maximum occupancy, whilst still maintaining excellent Thermal Comfort for the benefit of the building occupants and still providing the required waterside cooling.

The above is difficult to achieve with other Chilled Beam manufacturers products that are on the market, as usually when the fresh supply air volume is reduced, to below the designed setting, the air introduced into the room space from the competitors Active Chilled Beam no longer produces the desired Coanda Effect and therefore the air doesn't entrain across the ceiling and instead can dump into the occupied space, causing discomfort / draughts. Also, competitors waterside cooling falls off drastically due to the lack of induction.

Just like the rest of Frenger's highly efficient product solutions, Frenger's Active Chilled Beams have undergone extensive in-house testing allowing Frenger® to design and develop the optimal method of inducing room air and introducing fresh air to a room without causing draughts or excessive noise.

The ability to Turn Down the fresh air supply pressure, whilst still providing induction and Coanda on discharge maintains good Thermal Comfort and allows for a more energy efficient and flexible way of building management for building owners and facility managers.

This reduces the energy consumption on the other HVAC systems in the building, particularly the Air Handling Units (AHUs), therefore lowering running costs, reducing the buildings operational carbon emissions, and extending the life of the building systems.

The graph below shows how the waterside cooling of Frenger’s Active Chilled Beams is reduced during the ‘Turn Down’ facility, allowing the flexibility to match the requirements relative to the number of occupants in the occupied space.

Chilled Beam Turn Down Graph

Turn Down Performance Examples:

  • At 100Pa Active Chilled Beam Static Pressure:-

Design Air Volume = 100%
Waterside Cooling 100%

  • At 60Pa Active Chilled Beam Static Pressure:-

Design Air Volume = 79%
Waterside Cooling 89%

  • At 40Pa Active Chilled Beam Static Pressure:-

Design Air Volume = 63%
Waterside Cooling 76%

  • At 15Pa Active Chilled Beam Static Pressure:-

Design Air Volume = 39%
Waterside Cooling 48%


When room spaces have less occupants than 100% of design, a lower supply air volume and the lower waterside cooling should still meet the respiratory requirements (8-15 ltrs/sec per person) and waterside cooling to maintain the design room temperature.

The above information is to help enable engineers to calculate the possible Turn Down for their particular projects.