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Chilled beams are not new and have in fact been popular in Scandinavia for some 20 years. In the early to mid nineties chilled ceiling technology was pioneered on a few projects, but the limitation of output (a maximum of around 70 W/sq m) required additional chilled beams to be installed on the perimeters to counteract the solar gain caused by large window areas typical in modern office buildings. Since that time, chilled beams progressively overtook chilled ceilings and then an important variant in the form of multi service chilled beams (MSCB) was introduced by TROX .First used in 1996, MSCBs are fitted directly to the building’s structure so there is no need for a suspended ceiling. They enable the architect to style the appearance of the building services andcan form a distinctive architectural feature in any commercial application, whether newor refurbished. They can also carry pipework and electrical and data wiring, particularlyuseful in buildings that make a feature of exposed ceilings.
Passive chilled beams rely on natural convection and chill the warm air that rises andpasses over the coil. Active chilled beams have a primary air supply with nozzles or holes that jet the primary air out across the ceiling. The multi-service chilled beam (MSCB) is a more recent development which combines cooling and/or heating with a range of other services including:
• Sprinkler systems
• Lighting
• Public address systems
• Smoke detectors
• PIR sensors
• BMS cables
• Voice and data cables
• CCTV
• Smoke sensors
London based Austin Smith Lord used the TROX MSCBs on their recently completed £7.2 million New Prospect House project. Duncan Bainbridge, “We used the TROX system as it was an effective and sound product. It was key to us achieving a BREEAM Excellent rating on the project.”
MSCBs work by ducting primary air to the beams and then discharging it through calibrated nozzles. This encourages room air to pass over the beam’s cooling coils before supplying a horizontal discharge to the room via the integrated linear slot diffusers. The cooling is achieved through a combination of induced air flow and heat exchange across the cooling coils. Primary air is ducted to the beam and discharges out of induction nozzles. The discharge velocity from the nozzle is high relative to a small mass of air. The characteristics and energy of this jet induces warm room air across the cooling coil (which absorbs the heat from the airstream and cools it) and into the primary air stream. Thus, the mass of cool air induced into the primary air stream has the effect of reducing the air stream velocity as it mixes within the plenum chamber prior to discharging from the beam. This maximises comfort levels by preventing draughts.
TROX was nominated Martin Brett of Austin Smith Lord for the MSCBs used on their New Prospect House project in London.