THE EUROPEAN INFLUENCE
10/05/2007
Terry Farthing, Head of Communications at TROX UK, explains how progressively air distribution systems from Europe have had an impact on the UK market.
The air distribution market historically has been influenced by the American market, and the products that have been developed over there were soon commonplace in the UK. However in more recent times the European market has had a significant impact on the trends in the UK with some classic examples which have now become well established systems.
In the late seventies dual duct and constant volume boxes gave way to a new system which was fully variable air volume or VAV. This was developed for the American market as a completely flexible system which not only saved energy compared to constant volume or dual duct systems, but gave the property developer a system which could adapt to a wide range of cooling loads and thus potential tenants. It soon became popular in the UK with a number of companies manufacturing VAV systems.
In the 1980’s most property developments were VAV and the ubiquitous fan coil was relegated to second choice. Such was the popularity of VAV systems that letting agents advised clients that unless they installed VAV air conditioning then rental values would be lower.
Drawbacks of VAV systems were that at lower air volumes there could be a risk of the diffuser dumping, and at minimum airflow the unit was so quiet complaints could arise as people didn’t think the air conditioning system was working. These were overcome by another development of VAV, the fan powered VAV unit. It had all the benefits of VAV but was also a constant volume device. The primary air volume was varied and the secondary air flow via the fan gave a more or less constant total flow. In 1991 the VAV market reached its peak with a market size approaching £30M. Today the market has reduced dramatically to a figure of around £7M.
So what happened, and why have changes occurred?
First of all the influence of European systems gained pace when architects and consultants took on many projects in Europe due to the downturn of work in the UK and elsewhere.
Secondly, and possibly for a similar reason European manufacturers were trying to expand their market share in the UK and strengthen their sales and marketing teams. Through these two factors the market became more exposed to European systems and products. A third influence was the harmonisation of European standards that had been taking place for sometime and was still continuing with no early progress. For example, the new standard on fire dampers was first in committee stages during the early 1990’s within CEN and it is only in April 2007 that the new BS-EN 1366 was adopted.
These influences brought about significant changes to the terminal air distribution market. For example chilled ceilings which were very popular in Europe as passive cooling systems. They produced very high levels of comfort with low velocities and low air turbulence. They were generally used in conjunction with floor diffusers in the displacement mode, also a European type system.
The major difficulty with chilled ceilings was that the heat loads within Europe tended to be very much lower than those required in spec office buildings in London and the 70 – 80 w/m2 was insufficient to win a large share of the market. So at this stage another European system was integrated with the chilled ceilings, i.e. chilled beams. These were initially installed on the perimeter of buildings to deal with the high heat loads and chilled ceilings for the central areas. It soon became apparent that the chilled beam had many advantages over passive chilled ceilings and buildings very rapidly went completely over to chilled beams. It was at this point that TROX UK looked at using their European beam expertise to develop an exposed multi service chilled beam (MSCB’s), the first installation being for the Barclaycard Centre in Northampton in 1996. MSCB systems was a new idea and took time to develop, however it is now one of TROX’s most important terminal air distribution systems. It is rapidly taking over from fan coil systems and being exported to many countries outside of Europe.
Displacement flow was more of a Scandinavian system and although it is used in the UK it tends to be for bespoke comfort air conditioning solutions, or alternatively industrial type establishments.
Further European influence came with the introduction of high induction diffusers of the UK market. These can either be slot diffusers with the high induction air control cylinder mounted centrally, or the swirl type which are suitable for high heat loads and air change rates up to 30 per hour.
The most recent European system that could take off in the UK is decentralised air conditioning. With this system the air conditioning is incorporated into the cladding which does away with space grabbing air handling plant rooms. It also removes the need for false ceilings and distribution ductwork ensuring effective and flexible use of the office space.
The UK air conditioning sector is facing one of its most significant challenges in reducing the carbon footprint of buildings. Through investment in R & D resulting in innovative energy saving solutions, TROX is well placed to play its part. Obviously the European connection will help as well.
Download picture FSL Decentralised Ventilation (original)
Download picture VSD Slot Diffusers (original)
