Terry Farthing, head of communications at TROX UX explores why the approval rating of MSCBs has rocketed.

Exposed multi-service chilled beams (MSCB) have enjoyed astronomic growth over the last few years and are having a major impact on the terminal air conditioning market.

Research organisation BSRIA estimates that the market for chilled beams and ceilings (the latter having become a relatively small, niche sector) grew by 33 per cent in 2006 compared with 2005 and predicted further growth of 40 per cent for last year.

However the all embracing term chilled beam includes, of course, the MSCB which in value terms is between 2 and 5 times greater than that of a commodity beam.  As such the great surge in market value reported by BSRIA has been heavily influenced by the popularity of the MSCBs.

Indeed, over the last five years, they have really come of age, with leading developers such as Land Securities and Stanhope acknowledging their benefits and starting to install them on increasingly large and prestigious projects including speculative office developments.

There are, in fact, a wide range of good reasons for the enthusiastic approval with which MSCBs are now being greeted. One of the most important is related to their superb energy efficiency performance. A raft of legislation on energy saving, including the revised Part L regulations, has helped establish MSCBs as a popular choice among building services professionals.

MSCBs do not require a secondary fan so they are inherently more energy efficient than fan coil units. On top of this, they use higher chilled water flow temperatures (around 14 deg C), which means that chillers do not need to be working for a significant part of the year  and cooling is, quite literally, freely available.

The higher water temperatures used by MSCBs also lead to a significant sustainability dividend. Sustainability implies meeting the needs of the present without compromising the ability of future generations to meet their own needs and, in the context of MSCBs, it relates particularly to the longevity of human ecological support systems such as our planet's climate.

Because they use water at relatively higher temperatures of around 14 deg C, MSCBs can use the cooling (or heating) energy in renewable geothermal resources such as groundwater.

The sustainability dividend also applies to the question of new build versus refurbishment in commercial building applications. Take, for example, a 1960s building that has reached the end of its useful life – we can knock it down and rebuild with all the energy consumption and resources this would take, or we can refurbish it. The latter was rarely an option before the development of exposed MSCBs because the low floor to ceiling height in this type of building made it impractical; traditional comfort cooling solutions such as fan coil units require a false ceiling which reduces the height. Hence, landlords tend to opt for expensive new (and therefore normally more spacious) buildings.

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. This, in turn, means that the slab to soffit height is sufficient, even in these very old buildings.

But low energy consumption and sustainability are not the only advantages of MSCBs. They also reduce the cost, time and effort involved in a building services installation because a range of services are integrated into a single, self-contained unit. And, because there are no filters to change and no moving parts in the unit itself, it is virtually maintenance-free.

Another benefit of MSCBs is their pleasing modern look which can be styled by the architect to form a feature of the building. And, using extruded aluminium sections allows longer lengths of straight beams in, say, an office application because their dimensions are more precise and they can be manufactured to a tighter tolerance than the alternatives, pressed or rolled steel, which can look distorted in long linear settings.

Off-site prefabrication of the beams enables a consistent high quality product to be achieved within a controlled environment. Prefabricating MSCBs in the factory also has a dramatic positive impact on their performance because the quality of the build can be tightly controlled and individual components can be tested so the professional team knows precisely how each will perform in a given space.

Prefabrication also improves speed, quality, safety and sustainability (waste materials can be recycled more easily in the factory, and traffic movements can be lessened, which is better for the environment).

Further advantages over fan coil systems include:

•        Lower sound levels because there are no terminal fans.

•        High quality comfort because supply air velocities are very much lower.

•        Lower whole life costs.

•        A net reduction in annual carbon emission of around 15per cent.

•        Reduced commissioning times and costs because the beams are “plug and play”.

As can be seen by their raft of advantages, the arguments in favour of MSCBs are compelling and becoming even stronger as new developments are introduced. For example, our own new high induction chilled beam engine offers an induction rate twice that of conventional beams. This enables the building services designer to halve the primary air volume, which saves energy and reduces the carbon footprint of the building. It also means smaller ducting can be installed, saving on material and costs and increasing siting flexibility.

Because of these advantages MSCBs are progressively being looked at as a short listed option which is put forward to the client.  This has meant greater focus on these benefits and in quantifying the value in terms of reduction in carbon emissions, whole life costs and capital costs, the factual evidence is weighing heavily in favour of MSCBs.  With this in mind I can only see further significant increases in the use of this system.

Download picture (original)

Download article (DOC format)