Chilled beams have been around in Northern Europe and Scandinavia for over 25 years but it is only in the last decade have we seen them become established in the UK market.  The so called European beams are more of a commodity product manufactured in rolled steel sections and as such limited to a standard range.

For chilled beams to become an attractive proposition in the UK a more flexible approach was required and this gave way to the ubiquitous multi service chilled beam (MSCB).  First developed for specific projects such as Barclaycard Northampton and LloydsBuilding in London, the MSCB gradually gained in popularity with its market size now equating to approximately ⅔ of the chilled beam market.

The total chilled beam market in the UK has had an annual growth over the last 3 years averaging over 30% per annum.  This increase in demand has meant that the chilled beam market has now overtaken the fan coil market in value terms with MSCB representing a major proportion.

This growth has not just been restricted to the UK market with many European and worldwide projects being completed by TROX.  Initially these MSCBs were being specified by UK architects and consultants working on overseas projects, but now the benefits of these systems are being well accepted by local teams.

Many markets have listed buildings within the city centres which are being refurbished and MSCBs are becoming the No. 1 option given that they can be installed where headroom (i.e. floor to soffit dimension) is very limited.

MSCBs have very good energy credentials since they do not need terminal fans and utilise elevated chilled water temperatures of 14ºC flow and 17ºC return.  Those higher temperatures mean that there is potential for significant periods of free cooling.

With active MSCB there has up until recently been the need to supply more air than just the fresh air requirements so that the beam would meet the cooling load typically up to 120Watts/m².  Research work has been ongoing to increase the induction rate so that the minimum fresh air requirement of 1.2 l/s/m² would be sufficient to create the induction necessary to meet these loads.

The original beam engine design is shown in diagram 1, and these units had induction rates typically around 4:1, which meant the airflow was quite high and well above the fresh air requirement to meet the cooling loads.

A new beam engine configuration was developed as per diagram 2.  Since the air path route was less torturous and specially developed nozzles were used induction rates were doubled up to a ratio of 8:1.  More development work, particularly on the nozzles, is ongoing and induction rates of 9:1 have been achieved in the initial detailed test work.  This means that the active MSCB can meet cooling loads up to 120 W/m² with total airflows much reduced and around the fresh air volume requirement.

This top discharge MSCB can operate at night as a passive beam with no primary air flow, and water being chilled by free cooling.  The natural circulation reverses the airflow path of the active beam and serves to cool down the building structure at night.

Sustainability is becoming another major influence in the selection of air conditioning systems.  With MSCB the chilled water temperatures are elevated, this means that renewables such as  ground  water can be more effectively utilised.  Also with sustainability the life of the building and system has to be considered.  Most pre 1970 office buildings have a low floor slab to soffit height. Traditional comfort cooling solutions require a false ceiling which reduces this height too much. Hence, landlords tend to opt for expensive new build to ensure a modern office environment and sufficient space for the increased cabling and other services.   However, MSCBs solve the space problem because they can be fitted directly to the soffit and be left exposed, meaning that there is no need for a false ceiling.   So MSCBs offer the opportunity to modernise and recycle older buildings – a more sustainable solution.

MSCBs have been developed and adapted for a variety of applications including hospitals, schools and universities, laboratories, airport terminal buildings, TV studios and of course office buildings.

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