OPPORTUNITIES IN THE GRILLES AND DIFFUSER MARKET
01/07/2008
ISM Swirl Diffuser fitted with central light
ISM Swirl Diffuser fitted with central light
Terry Farthing, Head of Communications at TROX UK Ltd discusses some of the threats and opportunities for grille and diffuser manufacturers.
The first thing we manufacturers must do is to get the message across about the importance of good air distribution.
Good air distribution should be draught-free and include good mixing of air so an even temperature is produced throughout the space. It should also include low air velocities so that the entire space is neutral to the occupants. In other words they should not even notice the air conditioning system is there.
All too often, particularly on the smaller project, the contractor chooses the cheapest products available which are mostly imports sold through distributors and not well supported by design advice. They are sold on the basis of “pile ‘em high, sell ‘em cheap” commodity products off the shelf and are usually simply filling a hole in the ceiling where the ducting terminates. Not air conditioning engineering or air distribution engineering at its best.
On the larger projects the consulting engineer is more liable to produce a detailed schedule providing specific air distribution performance criteria that must be met. The ability of manufacturers to demonstrate room air conditions via a mock-up is becoming an increasing consideration. Sophisticated computer analysis such as CFD (computational fluid dynamics) can relatively quickly look at a wide range of variants. However they cannot accurately predict the velocities that will exist in a room in specific circumstances and that is why there is no substitute for real live testing. Clearly not every job is big enough to warrant this type of testing but even in relatively standard applications diffuser performance data supported by such test facilities is a vital consideration.
The factors that are likely to most affect the size of the grille and diffuser market are trends in the air conditioning systems, the economic situation and imports.
Fan coil systems require mostly diffusers to distribute the conditioned air and whilst they have been the most popular system in recent times they are now under pressure from chilled beams which have their own inherent air distribution devices.
So the future shape of the grille and diffuser market could be significantly influenced by the popularity of the fan coil unit. For the last 40 years FCUs have been constant speed, constant volume devices and even when the load was at a low level the fans still operated at 100% - the energy consumption is therefore higher than it needs to be. With the advent of EC motors with infinitely variable speed the evolution of the VAV fan coil is taking place giving the fan coil system better energy credentials and in a better position to compete with chilled beams – good news for the grille and diffuser market.
One very serious consideration with VAV fan coils is that with standard diffusers there is a risk that the air will dump below, say, 60% of maximum. With conventional VAV the risk of dumping was a major concern for many designers. For VAV FCU to succeed and beat off the challenge of chilled beams this risk needs to be eradicated either through a thorough review of each diffuser’s performance or by utilising anti-dumping devices such as the Varyset plenum. This is a very simple device comprising of a segmented plenum box and counter balanced air operated damper. Note the damper covers only 2/3 of the spigot area. At 100% air flow the damper is fully open and air can flow into the plenum box as though it were a conventional unit. But as the air flow reduces so the damper closes, providing constant velocity to part of the diffuser which maintains the coanda effect. So if the VAV fan coil systems become more popular the future of the grille and diffuser market will be brighter.
What other innovations could impact on the grille and diffuser market?
Again it is important to look at the development of the chilled beam market to see if any factors could be used to influence innovations with grilles and diffusers. The major driver in the beam market has been multi service chilled beams – the main reason being the integration of all the services into one module.
This integration need not be restricted to chilled beams only. Integrated service modules (ISM) where the air distribution devices, lighting and other components form a complete prefabricated assembly installed into the ceiling. The ISM system has already been used on a few projects. This multi service approach to air distribution could be extended to most fan coil systems since there are a number of interesting benefits. The “multi service” approach means that the air distribution and other components can be designed to give a high quality aesthetic appearance. It also gives the architect more freedom to design and integrate the air distribution and to achieve the best overall finish. The ISMs are pre-fabricated and assembled in the factory and delivered to site as a composite unit. This pre-fabrication within a controlled factory environment gives improved quality and reduces installation time.
Another change that is well under way is the increasing popularity of high induction diffusers such as swirls and slot diffusers with air control cylinders. With the radial swirl diffuser air change rates of up to 30 can be utilised without compromising good air distribution. It is one of the most effective air distribution devices and is now becoming more popular with an improved overall appearance.
If the opportunities I have outlined are effectively promoted to the market place, I believe they will reduce the impact of any threats on the horizon.
Download picture (ISM Swirl Diffuser)
