Iskender Gençer, product manager for chilled beams, Trox UK discusses the sea change that is taking place in this now mature market.
In the last few years we have seen the market for chilled beams reach maturity in the UK. The technology is trusted and widely understood by the HVAC industry. The period of rapid R&D which saw chilled beam technology leap forward at a tremendous rate, has been replaced across the sector by the sort of incremental developments and enhancements associated with a mature technology.

Often, a mature market plateaus out at this stage but that is not the case with the chilled beam market. Just when the pace of technological development began to steady, there has been a sudden change of focus and the arrival of a new set of priorities from consultants and contractors. This has moved the goalposts and the questions asked about chilled beams today are very different to those of a year ago when specifiers were asking: 'Which is most energy efficient, a chilled beam or a fan coil based system?' But, in the intervening months, the discussion has moved on, and specifiers of chilled beams are now asking 'How can their energy efficiency be optimised? And can you provide me with proof that will demonstrate the advantages of chilled beams to my client in real terms?'

Discussions around energy efficiency are now drilling down to greater detail. Chilled beams are frequently selected because they provide an important point of difference/competitive edge for the site. For example, to reduce lifetime costs of ownership, and/or to make it more attractive for incoming tenants.

Specifiers want to know how the system performs as a whole, rather than a set of component-specific efficiency values. They want to know how equipment will perform at different times of day, throughout the year, and across a range of climatic conditions.

The EPC banding is often seen as being too broad to demonstrate fully the effectiveness of the product solutions they design/install. The best equipment selection in a band may represent many thousands of pounds of energy savings (and the accompanying carbon reductions) over the lifetime of the equipment compared with the worst equipment selection. Yet they both have the same broad brush rating.

To respond to specifiers' needs, we have continued to invest in our in-house laboratories at our site in Thetford, which is a global centre of excellence for chilled beam development.

In addition to a fan coil and a CO₂ IT cooling test rig, Trox UK has three test chambers dedicated to air distribution and chilled beam measurements. Each of these chambers is different in size, making it possible to simulate various room sizes with alternating ceiling heights and different floor areas. Solar gains, internal gains and glazing loads can all be simulated in these facilities and accurate temperature and velocity measurements can be recorded.

As part of an international company, Trox UK is also able to draw on equipment performance data from sites with significantly different climatic patterns.

Building simulation

In addition to its in-house resources, Trox has worked in collaboration with Environmental Design Solutions (EDSL) to supply actual performance data for components that can be inputted into its TAS building simulation software. All of the information supplied to EDSL relating to Trox products is based on aerodynamic and thermal measurements carried out in our state-of-the-art laboratories around the world.


Using our data, the TAS software can analyse the behaviour of a building on an hourly basis. By adding an additional layer, using one of 14 climate files for the UK, the TAS software can analyse the system at various peak and low loads across the year.

The analysis can support a planning application as an alternative to an SBEM monthly-based analysis. The speed with which it can be carried out (a matter of seconds), also makes it possible for various what-if? scenarios to be explored. For example, a system designer can compare technology choices, and optimise the building's CO₂ footprint.

Trox provided its measured test data for fan coils which is now used in TAS software calculations, and has also worked with EDSL to provide data for chilled beams.

Our work with EDSL has shown us how we can use chilled beams to achieve the best possible results in a mechanical system design.

The graph below shows energy consumption of the same building but incorporating slightly different designs. Both columns show a single chiller system, supplying chilled water at different temperatures to the ahu plant and the chilled beams (after mixing the flow with return to increase the supply temperature for chilled beams to 14°C+).

As the ahu plant is responsible for dealing with the latent loads in the space, the variation in chilled water temperatures will influence the water flow rates, or even the primary air flow rate depending on the requirements of the design. Chilled beams will also perform differently depending on the condition and the volume of the primary air.

After running the simulation and calculating the impact of these variations we are able to assess the difference in energy consumption for both applications, where one chiller has a lower COP working with a 6°C flow temperature compared with the other one working with 11°C.