Chilled Beams Design

In general, chilled beams are considered a more energy-efficient solution compared to conventional HVAC systems. Additionally, they have little to no moving parts, and they even operate quietly and demand little maintenance.

If designed properly, they can complement the aesthetics of a space and even create a draught-free environment. Chilled beams could be classified as either active or passive.

An active chilled beam (ACB) is considered an integral part of a mechanical ventilation system within a building. It lets fresh air in through a ductwork which is then injected to the beam via nozzles, thereby inducing air flow from the room below. After that, the air then passes through the beam fins where it is cooled and distributed afterwards.

Due to this process, an active chilled beam is considered more efficient in terms of cooling capacity compared to its passive counterpart, delivering around 500-800 watts of cooling for every linear meter. In some cases, it might also include a heating coil to heat up supply air when necessary.

Meanwhile, a passive chilled beam (PCB) tends to rely on buoyancy for creating air movement. As chilled water passes via the tubes, warm air will then rise toward the ceiling where it’s cooled by the beam and returns to the occupied space. Due to this, a passive chilled beam is capable of cooling without the need to use a fan. However, its cooling capacity is lower to that of an ACB, delivering only around 300-500 watts of cooling for every linear meter.

Aside from active and passive beams, chilled beams can also be classified into the following:

Applications

Active beams are ideal for the following applications:

• Schools
• Hospital roomsu
• Dormitories
• Hotels
• Spaces with sensible heating and cooling requirements
• Spaces that require low noise levels
• Spaces that have limited floor-to-ceiling height

On the other hand, passive beams work best on the following:

• Offices
• Libraries
• Lobbies
• Conference centers
• Spaces that require additional cooling

Design Overview

To make sure we can create the right chilled beam design for your building, we normally examine the following considerations:

• Controls

Passive, and even active, chilled beams can be considered self-regulating. As there is an increase in heat gain, the mean water temperature difference will progressively increase as well, thereby increasing overall cooling capacity.

• Condensation Prevention

 Chilled beams are designed to use the dry cooling principle to eliminate the risks of condensation by choosing the chilled water flow temperature, supply air conditions, and ventilation rate. The dehumidification of the primary air supply is a major factor for preventing humidity levels from surpassing the dew point, hence preventing condensation.

To guarantee the dehumidification of supply air during high outdoor temperatures, it is important to size the air handling unit’s cooling cool to dehumidify outdoor air and allow for internal latent gains. Additionally, the humidity ratio must be low to allow ventilation airflow to compensate for the internal humidity loads.

• Ductwork Requirements

Since the primary airflow rate is based on fresh air requirements, ducts are designed to be relatively small. In a traditional ACB, the ductwork is proportionally balanced. If not, constant-pressure control dampers are necessary.

It’s also important to take note that PCBs that work with separate supply air systems tend to operate at minimum ventilation rates. As a result, smaller duct dimensions are used. In the same manner, ACBs can also operate at minimum ventilation rates to create enough induction of secondary air, thereby providing the necessary waterside cooling.

• Water Distribution

Chilled beams normally operate at temperatures between 14 and 18 degrees Celsius. If ACBs are used for both cooling and heating purposes, then they’ll have to use two separate water circuits.

Due to the difference between the flow water and room air’s temperature in a dry cooling system, the sizes of the pipes used will be larger compared to the ones in condensing systems. Additionally, distribution pipework is sized to a 50 to 100Pa/m pressure drop as a means of balancing the pipework system via small pressure drops within the balancing valves. This is designed to avoid or prevent noise generation.

The choice of pipes could either be plastic, copper, or steel. However, they have to be properly insulation in order to reduce overall energy consumption. Since chilled beams work above the dew point, a vapor barrier is no longer necessary as long as the inlet water temperature is maintained above the room and void’s dew point temperature.

Meanwhile, the primary distribution pipework must be installed at a higher location than the beams.

•  Ventilation Rate

Ventilation rates can be computed in accordance with the local building regulations within your area. For example, if you’re from Chicago, you need to comply with the local building regulations in the city.

ACBs typically use constant airflow. However, it’s also possible to use lower supply air temperature as long as the room system can heat the cold supply air to prevent the room from overcooling.

If the active chilled beams’ length is predetermined, you’ll have to follow the primary air flow rate that your manufacturer specified. This way, you’ll be able to achieve optimal cooling performance and ensure effective heat transfer. Make sure you don’t set the primary airflow rate too high as it will only result in excessive induced airflow which could lead to droughts.

Now that you’ve had an understanding of the points we normally consider in designing your chilled beam, the next thing is to know the main things you have to consider in your desired chilled beam. They are as follows:

• Acoustics

Both active and passive chilled beams operate quietly, although active beams tend to be a bit noisier compared to their passive counterparts. The noise level usually depends on various factors such as the diameter of the nozzle, supply airflow rate, and frequency.

The size of the nozzles will vary from one manufacturer to another, although you can have your own custom size specified. It’s possible to adjust such variables so you can control how much noise is generated and meet your acoustic demands.

• Access

Chilled beams will require regular maintenance to keep them in ideal working conditions, which is why access to their components is an essential factor you should consider in your design. Access to the chilled beams will depend on several factors such as the design of their casing and their mounting. For chilled beams which are installed above a ceiling, its access can be determined by the ceiling’s design.

Meanwhile, flush mounted units can be easily accessible through various means such as using drop-down panels.

• Design

There’s a wide range of chilled beams available on the market these days. However, you always have the option of going for bespoke variants based on the design we provide you. With that, you will be able to vary the size, color, and shape to meet your specific demands.

When it comes to multi-service beams, you can find a variety of building services which could be incorporated. When looking for possible solutions, we recommend that you pay close attention to the details of our design and any design constraints during our designing process.

• Cost

Apart from the initial cost of designing your chilled beams and having them manufactured, you should also consider other possible expenses such as monthly recurring energy bills and ongoing maintenance.

Since chilled beams have typically low maintenance requirements, their lifetime maintenance costs are way lower compared to other HVAC systems. However, it’s important to conduct your own project life cycle analysis since there can be variations in your building’s design. You have to take special care to reduce energy consumption, lessen maintenance requirements, and prolong its life expectancy.  

There are other systems with lower initial cost but demand higher maintenance and operational costs. Fortunately, a well-designed chiller beam system can resolve that issue beforehand.

• Flexibility

Chilled beam systems could be designed to be flexible, especially in terms of space. It’s possible to customize the size of terminal units during the designing process in order to fit certain layouts. It’s also possible to add or remove partitions whenever necessary. However, this will depend on the individual system design.

Just like any other system, there can be a trade-off between flexibility and cost. Typically, a chilled beam system with higher flexibility will require additional ductwork, which in turn leads to additional system costs.

How Can New York Engineers Help?

Here at New York Engineers, we can help you conceptualize and formulate an effective design for your chilled beam systems. Depending on your preference, whether you want to go for an active or chilled beam, we can create the right system design that will accommodate your needs, particularly in terms of budget, efficiency, floor space, and performance.

Our professional designers and engineers make use of the latest tools in the MEP (manufacturing, engineering, and plumbing) industry such as Revit and AutoCAD to bring your design to life. We also render your finished design in a 3D environment to give you a preview of how the system will work in real-life scenarios and even resolve any possible issues that might be associated with your building’s layout.

With our years of experience in the industry, we can only guarantee you the best chilled beam design services at very competitive prices.

What are you waiting for? Avail of our services now!

Feel free to contact us or visit any of our physical branches in New York, Chicago, and New Jersey.