Chilled beams offer an effective cooling solution and can help reduce a building's energy footprint significantly, claims Wander ter Kuile.
It's a tough market with businesses under pressure to remain profitable, but also show a commitment to reducing their energy and maintenance costs, and reduce their carbon footprints. Carbon dioxide (CO₂) emissions from the building sector are estimated to account for some 30-40 per cent of global energy use. Little wonder then that energy-efficiency is a major challenge for the built environment and this is fuelling increased sales for chilled beams.

The tightening of building regulations and more stringent EC directives are good news for the chilled beam industry which has fan coils constantly snapping at its heels. But the potential energy reduction of using chilled beams instead of a traditional air conditioning system can be as much as 50 per cent depending on the type of system, climate and building.

Competing head on

The two technologies compete head on yet there are applications where a chilled beam will be far more suitable.

A chilled beam is essentially a cooling coil without a fan, used to remove the sensible heat from the occupied area. The application of chilled beams is quite practical, warm air rises; it is cooled by the chilled beam, and circulates back to the floor. Then the cycle repeats.

Chilled beam manufacturers offer a significant reduction in energy consumption (some 20 per cent) over standard hvac, excellent thermal and acoustic properties and a reduction in a building's carbon footprint.

They are suitable for renovations, retrofits as well as new builds and tend to be favoured by architects for their clean lines and aesthetics as well as their energy saving properties.

Fan coils compete head on. They have a lengthy pedigree and are familiar to contractors and installers who have grown up with them. Many will argue that fan coils are now just as energy efficient thanks to the introduction of EC motors. They might also claim that, whereas fan coil units are supplied for cooling and heating, most chilled beams are cooling only. In fact, this is not the case; many chilled beam manufacturers now offer cooling and heating.

Multi-service chilled beams (MSCBs) - which can also incorporate other services such as lighting, BMS sensors, fire alarms, sprinkler systems and heating (four-pipe systems) - have seen significant growth as these can use either active or passive chilled beam technologies.

Such flexibility in a cooling system is attractive to architects and m&e consultants, especially since the units can be prefabricated off site, delivered and plugged in when ready for use.

Bringing many services together in a single integrated unit has other benefits too. For example, MSCBs can be used in spaces where the floor-to-slab height is minimal and they provide a single source of responsibility for the design, supply and integration of all services, ensuring reduced cost, on-site time, labour and project management.

Chilled beams generally also offer a more hygienic alternative to air conditioning systems hidden within ceiling voids which could put the health of a building's occupants at risk if regular cleaning and maintenance is not carried out.

Dust and other debris can get trapped in voids at the fit out stage and remain there for the lifespan of the building. Depending on the environment, mould and bacteria could also present a problem. Unless building owners adopt a rigorous cleaning regime the health of occupants could be compromised.

The Health & Safety at Work Act 1974 places legal responsibility on employers and those who control buildings to monitor and regularly sanitise ventilation ductwork. But, how many building owners run to the expense of regularly cleaning ductwork and the actual ceiling void?

This is particularly important in food outlets. Healthcare providers are also attracted to chilled beams to provide not only an energy efficient solution, but also one that can be easily cleaned.

But it is the green aspects of chilled beams that are particularly attractive to building owners and design professionals. Water is a more efficient means of conveying cooling energy than air and thus reduces the fan energy required. While primary air is still delivered to the chilled beam, the majority of space cooling is handled with pipes and pumps, not ducts and fans.

Chilled beams work on higher operating temperatures than conventional air conditioning systems and this enables free-cooling when external ambient temperatures allow producing greater energy efficiencies.

Unfairly viewed as expensive

There are no internal fans or filters to break down or clean and this ensures that maintenance costs are low. No noise and a reduction in a building's life costs also make chilled beams an attractive solution.

Chilled beams are often unfairly viewed as an expensive solution, but the technology has not only proven itself to be more energy efficient than equivalent conventional systems, but also reduces sheet metal cost by eliminating a significant amount of ductwork.

Prices are also coming down and will continue to do so as demand and competition increases.

• Wander ter Kuile is technical manager of Waterloo Air Products