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Operation and benefits of active chilled beams

31.10.2025.
Airvent

Chilled beams – efficient comfort

Better for people. Better for the environment.

Scandinavian building design is defined by functionality, simplicity, and long-term sustainability. Chilled beams align naturally with these principles – a quiet, reliable solution with no moving parts, combining the high thermal capacity of water with the induction effect of air. The result is stable indoor comfort, low energy use, and minimal maintenance. The following sections outline how chilled beams work, their key advantages, and where they perform best – giving building owners, designers, operators, and users a clear foundation for sound, practical decisions.

Conference hall with chilled beams

 

A comprehensive solution

A chilled beam is a hybrid unit that enables cooling, heating, and ventilation within the same product. When connected to water and air networks, it delivers these functions quietly and efficiently. Its low installation height allows flexible interior planning, while the clean, discreet design fits naturally into modern architectural environments.

01

Overview

Operating principle

What is a chilled beam?

Principle and advantages of the active chilled beam

The origins of the chilled beam concept date back to the mid-1980s, when the first passive beam was installed in an office building in Stockholm. After the initial installations, the passive beam – serving only as a cooling element – was further developed to increase capacity and functionality, leading to the introduction of the active chilled beam

An active chilled beam is a ceiling-mounted unit that combines fresh air supply with cooling and heating by drawing room air through a water-based heat exchanger using the induction principle.

Compared to conventional ventilation systems that rely solely on air for cooling, active chilled beams operate with smaller air volumes, which allows for smaller ductwork, lower energy use, reduced operating costs, and a smaller carbon footprint.
 

Konferenciaterem klímagerendákkal – illusztratív fotó

Types

Chilled beam types

To meet different architectural, interior design, and technical requirements, chilled beams are available in several configurations. This makes it possible to select the most appropriate solution for each project, both in terms of performance and appearance. The two main types are active and passive chilled beams, illustrated in the diagrams below.

Active chilled beams

Active chilled beams include a connection for primary air supplied from a central air handling unit. The conditioned air enters the plenum chamber and is discharged through shaped nozzles, creating an induction effect that draws room air through the heat exchanger. The mixed air is then supplied back into the room. Through this combined function, active chilled beams can provide ventilation, cooling, and heating within a single system. Depending on the application, they can be integrated into suspended ceilings or installed as exposed units below the ceiling.

Airvent solutions:

OptimAir, PremiAir, FreeAir, HotelAir are Airvent’s active chilled beams. Go to product overview →

Passive chilled beam

Passive chilled beams

Passive chilled beams have no air connection. They rely entirely on natural convection: as room air cools over the heat exchanger, it becomes denser and sinks, drawing warmer air from the ceiling zone through the coil. With lower cooling capacity, passive beams are typically used for supplementary cooling or combined with other heating elements, such as radiators.

Airvent solution:

PassiveAir is Airvent’s passive chilled beam. Go to product →

Operation

Operating principle of active chilled beams

Active chilled beams condition the room using two parallel energy sources. Approximately 70% of the total cooling or heating output is provided by water circulating through the coil, while the remaining share comes from the treated primary air supplied by the central air handling unit. This combined approach increases overall energy efficiency and ensures stable, comfortable conditions throughout the occupied zone.

Chilled beam cross section 1 2 3 4

Operating process

1Supply of primary air

The air handling unit delivers pre-conditioned air to the chilled beam’s plenum chamber at a defined pressure and flow rate. From there, the air passes through a row of precision-formed nozzles, creating the induction zone where air movement begins.

2Induction

As the primary air exits the nozzles, its velocity generates a low-pressure region above the coil in accordance with the Bernoulli principle. This draws room air through the perforated front panel and across the heat exchanger, maintaining continuous air circulation inside the beam.

3Heat exchange

The induced room air flows through the coil and exchanges heat with the circulating water. The large heat transfer surface and the high thermal capacity of water allow effective temperature control with relatively small water volume flow. Typical supply water temperatures are 14–18 °C for cooling and 30–45 °C for heating, which makes chilled beams well suited for use with low-energy systems such as heat pumps.

4Air mixing and discharge

The primary and induced air mix inside the beam before being supplied back into the room through the side outlets. The airflow attaches to the ceiling surface through the Coanda effect, spreading evenly across the room and ensuring draught-free comfort. The result is a quiet, consistent, and energy-efficient indoor environment.

Installation and operation 

Installation types

Ceiling integrated Exposed

Recessed – ceiling integrated – chilled beams

Ceiling-integrated chilled beams are installed flush with the suspended ceiling, leaving only the front panel and narrow air slots visible. The ceiling surface itself enables the Coanda effect: supply air adheres to the ceiling, spreads evenly across it, and descends gently into the occupied zone without draughts. This discreet design is ideal for smaller or larger offices, and other interiors where a clean ceiling line is part of the architectural intent. Adequate ceiling void space is required, and coordination with the ceiling layout should be planned early in the design stage.

Airvent solutions:

Our OptimAir, PremiAir and HotelAir models are suitable for ceiling-integrated integration.

Suspended – exposed – chilled beams

Suspended chilled beams are mounted visibly below open ceilings, creating a clear architectural feature while keeping the full ceiling height available for other installations. When conventional, integrated chilled beams such as PremiAir or OptimAir are preferred, optional Coanda frames can be fitted along their sides. These frames act as a virtual ceiling, guiding the supply air horizontally across the room and ensuring draught-free air distribution even in large or open spaces such as offices and studios.

Airvent solutions:

For exposed installation, our FreeAir and PassiveAir chilled beams offer the optimal solution, while the OptimAir and PremiAir models can also be used when equipped with separate Coanda frames.

02

Benefits

Advantages

Benefits of chilled beams

Consistent thermal comfort and even air distribution

Active chilled beams ensure a stable indoor climate by combining ventilation, cooling, and heating. The induction principle promotes uniform air mixing, preventing draughts and temperature variations, creating a comfortable and controlled environment.

No risk of condensation
No risk of condensation

Chilled beams operate without the need for condensation trays or drainage systems. By maintaining water temperatures above the dew point, they eliminate the risk of condensation, ensuring reliable performance without additional maintenance requirements.

Continuous supply of fresh air
Continuous supply of fresh air

Chilled beams integrate fresh air supply as a standard feature, providing a continuous flow of conditioned outdoor air. This ensures good indoor air quality without relying on recirculated air.

Energy efficiency
Energy efficiency

Operating at higher water temperatures than conventional air conditioning systems, chilled beams improve cooling efficiency while reducing overall energy consumption. Using water as the primary cooling medium is significantly more efficient than air-based systems, resulting in lower operational costs.

Optimised use of space
Optimised use of space

Chilled beams require significantly smaller air ducts and air handling units than conventional systems, allowing for efficient use of ceiling space. Their compact design makes them particularly suitable for buildings with restricted ceiling heights or where architectural considerations limit available space.

Demand-controlled ventilation and individual climate control
Demand-controlled ventilation and individual climate control

Chilled beam systems can be integrated with demand-controlled ventilation (DCV) strategies, adjusting airflow and cooling output based on occupancy and indoor conditions. This optimises energy use and enhances overall system efficiency.

Low maintenance
Low maintenance

With no moving parts, filters, or condensate trays, chilled beams require minimal maintenance. The absence of mechanical components reduces the risk of failure and ensures long-term operational reliability.

Sustainable and cost‑effective solution
Sustainable and cost‑effective solution

By reducing reliance on large air ducts and lowering energy consumption, chilled beams contribute to efficient building design and sustainable operation. Their integration with demand-controlled ventilation and high-efficiency cooling makes them a highly sustainable choice.

Stakeholders

Who benefits?

Building owners Building owners – Chilled beams provide a solid foundation for energy-efficient and cost-effective building operation. Their compact form saves valuable space, while demand-controlled operation and minimal maintenance help achieve higher energy classifications and long-term property value.

Architects Architects – With their neutral appearance, chilled beams integrate naturally into any interior – whether recessed into the ceiling or installed visibly within the space. Their low installation height and optional colour finishes provide flexibility in both architectural and interior design, supporting visual intent as well as functional requirements.

Mechanical engineers Mechanical designers – Active chilled beams combine heating, cooling, and ventilation in a single, controllable unit. The wide product range makes it easy to select of the right capacity for each space. Designers can rely on our well-designed online selection software and verified performance data to support efficient planning, documentation, and coordination.

Contractors Contractors – Standardised mounting brackets, quick-connect water couplings, and pre-configured control options simplify installation and commissioning. Once installed, the system requires minimal intervention, ensuring reliable and reliable operation over time.

End-users End users and operators – Chilled beam systems create comfortable indoor environments with even temperature distribution, silent operation, and draught-free air distribution. With no moving parts or condensate formation, maintenance is minimal – providing quiet, reliable comfort year after year.

03

Technical parameters

Technical parameters

Structure and main components

The design of a chilled beam is guided by three guiding principles: functionality, durability, and easy integration. Below is an overview of the main components found in active chilled beams.

01 Anatomy of a chilled beam →

Click on the numbers above to explore the key components of chilled beams.

02 Plenum

The plenum, made of galvanized steel, provides structural rigidity and stable suspension for the chilled beam. Its geometry is optimized to ensure uniform airflow and meet the performance requirements of each model. Primary air is connected through a standard circular duct spigot with airtight sealing.

03 Nozzles

The precision-formed fixed or adjustable nozzles create the induction effect that defines the chilled beam’s performance. Their geometry and arrangement determine the airflow, pressure drop, induction ratio, and sound level. High-velocity primary air leaving the nozzles mixes efficiently with room air, ensuring stable and comfortable conditions.

04 Front panel and diffuser frame

The outer diffuser frame and folded front panel – made of aluminium or steel – form the discharge slot that guides the supply and induced air into the room. Using the Coanda effect, the airflow follows the ceiling surface, ensuring draught-free operation, smooth horizontal distribution, and uniform temperature throughout the occupied zone.

05 Coanda frame

Available as an optional accessory when PremiAir or OptimAir chilled beams are installed in a suspended configuration. The Coanda frame functions as a virtual ceiling, allowing the supply air to attach to its surface and travel horizontally across the room. This extends the throw distance and improves overall air distribution within the space.

06 Heat exchanger

The heat exchanger transfers heat between the water circuit and the induced room air. Made of copper tubes with aluminum fins, it ensures efficient energy exchange and stable performance in both cooling and heating modes. Its geometry supports rapid thermal response, while the durable design offers long service life and easy maintenance when required.

07 Air deflectors

All Airvent chilled beams are equipped with air deflector fins as standard. Each deflector can be manually adjusted on the discharge sides to guide airflow direction and modify throw length as needed. This enables flexible fine-tuning of the air pattern, ensuring a comfortable and draught-free indoor environment.

The illustration above shows the components of the PremiAir 1800 chilled beam.

Design guidelines

Key design guidelines for chilled beam systems

To achieve the desired comfort levels and maintain high energy efficiency, several key parameters should be considered during system design. These values may be adjusted according to room function, comfort criteria, and overall building system configuration.

Installation height Installation height – Active chilled beams: up to 5 m above floor level; Passive chilled beams: up to 6 m above floor level

Primary air volume Primary air volume – The primary air must at least meet the ventilation requirements of the space. For higher cooling demands, the air volume may be increased if the water-side performance alone is not sufficient. Typical supply range: 5.5–12.5 m³/h (~1,5-3,5 l/s) per m², depending on room use and fresh air demand. To prevent condensation, the dew point of the treated primary air must remain below the chilled beam’s water supply temperature.

Supply water temperature Supply water temperature – Cooling: 14–18 °C, with a recommended ΔT of 2–4 K for efficient operation Heating: 30–45 °C, suitable for low-temperature systems and ideal for heat pump applications.

Air-side pressure drop Air-side pressure drop – Typical range: 50–100 Pa, depending on room function, noise, and performance requirements, influenced by nozzle geometry and airflow rate

Building structure and operation Building structure and operation – To avoid moisture ingress, a slightly positive room pressure is recommended. Chilled beams must always operate in dry conditions, ensuring that the dew point of the primary air remains below the water temperature.

Acoustics

Acoustic characteristics

Chilled beams operate at low noise levels, meeting the requirements of office and healthcare environments.

 

Type
Typical sound pressure level*
Note
Passive
≤ 15 dB(A)
No primary air, no moving parts → effectively below background noise
Active
20 – 30 dB(A)
Complies with office (≤ 35 dB(A)) and healthcare (≤ 30 dB(A)) limits

* The laboratory measurements were carried out based on the ISO 9614-2 and ISO 11691:1995 standards.

04

Operation

Application

Application conditions and use cases

When are chilled beams ideal?

Chilled beams perform best in environments where the cooling demand is mainly sensible, meaning driven by temperature differences rather than humidity. For consistent comfort and reliable operation, the indoor humidity should remain moderate and well controlled. Under these conditions, chilled beams deliver their key advantages: high comfort, low energy use, silent operation, and discreet integration architectural integration.

 

Recommended applications

  • • Buildings requiring integrated cooling, heating, and ventilation in one coordinated system
  • • Rooms with moderate humidity, where relative humidity typically stays below 60%
  • • Zones where draught-free comfort and individual room control are priorities
  • • Typical examples include offices, meeting rooms, laboratories, hotel rooms, hospital wards, and educational spaces
  • • Architecturally demanding projects with limited ceiling space or high visual standards, such as refurbishments or design-driven interiors

Not recommended for

  • • Areas with high humidity or insufficient dehumidification
  • • Rooms with operable windows used for natural ventilation, where air infiltration cannot be controlled
  • • Spaces with rapid or extreme heat and moisture fluctuations, such as sports halls, swimming pools, or event venues

Humidity requirements

Chilled beams operate with dry cooling, meaning the dew point of the primary air must always remain below the supply water temperature. To ensure condensation-free and stable operation:

  • • The primary air must be dehumidified by the air handling unit
  • • The building envelope should be airtight, preventing uncontrolled air leakage and moisture ingress

When these conditions are met, chilled beams provide stable, energy-efficient, and reliable performance all year round.

Hygiene

Hygienic and operational safety

Safe and hygienic operation is an integral part of chilled beam system design. Several built-in principles and control functions ensure long-term, reliable performance.

Dew point monitoring

The control system continuously ensures that the dew point of the supplied primary air remains below the water supply temperature, effectively preventing condensate formation.

Water temperature limitation

Automatic safeguards prevent overcooling and maintain dry operation, protecting both the beam and surrounding surfaces from condensation.

Dry operation principle

Because chilled beams operate without standing water, the risk of bacterial growth or legionella formation is virtually eliminated.

Low air velocity

The low air movement characteristic of chilled beam systems contributes to a clean, hygienic indoor environment with minimal dust circulation.

Maintenance

Maintenance recommendations

Chilled beams are low-maintenance systems, but to ensure long-term, reliable, and hygienic operation, the following inspections are recommended

 

Activity
Recommended frequency
Note
Heat exchanger cleaning (vacuuming/flushing)
At least every 2 years
Can be done more frequently depending on dust accumulation
Water quality check
Annualy
Especially important in closed systems, particularly at low water temperatures
Air handling unit filter inspection
Quarterly
Should be documented, easily accessible, and part of the building’s regular maintenance routine

Service life

Durability and lifespan

Chilled beams are designed for long service life, typically around 20 years, corresponding to the lifespan of the heat exchanger itself. Their construction – using copper tubes, aluminium fins, and steel casings – ensures mechanical stability and long-term reliability.

With no moving parts, the risk of wear or failure is minimal, resulting in one of the lowest maintenance needs among modern building climate systems. When operated with proper water quality and air handling conditions, chilled beams maintain consistent performance and efficiency over decades of use.

Sustainability

Environmentally conscious operation

In line with Scandinavian design principles, chilled beam systems promote environmentally responsible and economically sustainable long-term operation. With low specific energy use and minimal maintenance needs, their total life cycle cost (LCC) remains favourable, offering measurable savings for both investors and building operators.

Using water as the primary heat transfer medium – at higher operating temperatures than, for example, fan coil systems – significantly reduces air-side demand, electrical energy consumption, and ductwork size. As a result, both installation impact and operational footprint are substantially lower.

The condensation-free “dry cooling” principle ensures hygienic performance, while the closed water circuit prevents stagnant water, eliminating the risk of legionella formation.

All Airvent chilled beams are covered by verified Environmental Product Declarations (EPDs), ensuring transparency in environmental performance throughout their life cycle. More on EPDs →

— Kecskemét, Hungary 2025

—
Text: Michael Pataki; Roland Fingerhut
Illustrations: Daniel Erdélyi; Ferenc Rosner

Airvent manufactured active chilled beams

Airvent chilled beams

Comprehensive solution for ventilation, cooling, and heating

Introducing our in-house manufactured models: PremiAir, OptimAir, FreeAir, and HotelAir – explore the range of Airvent active chilled beams. Go to the product showcase page→
 

Tags
Sustainability Efficiency Chilled beam Quality Airvent-made

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