Peter Lowther, managing director of Ability Projects, explains the Matrix II fan coil units and why they take the commissioning process to a whole new level.
Ability commission-less Matrix II fan coil units are special, in that their individual air volumes per duct run and design heating and cooling water flow rates are loaded into the terminal controller strategy during manufacture at the factory.

Thus, when the units are installed on site, they are able to sense their surroundings and adjust automatically to provide and maintain the factory preset air volume and water flow design values. The commissioning process therefore, becomes one of mere 'checking' rather than 'setting'.

The original Matrix fan coil unit was first marketed by Ability in 2006. Unlike conventional EC fan coils, however, the Matrix unit provides individual and infinite speed control of each of its fans.

Thus a Matrix unit can be air flow balanced by adjusting the fan speed alone, without the need for volume control devices. Air volume balancing is performed via a wireless laptop without VCDs and without recourse to physical contact with the unit. The real time saver, of course, is that once the first unit is fully set and balanced, the same instructions can be transmitted wirelessly to all the other fan coils on the project having the same installed condition.

Significantly reduced

Ability has supplied Matrix units on a number of large projects and the overwhelming evidence from these sites is that commissioning times have been significantly reduced and accuracy improved.

Matrix also possesses two important additional features, which help reduce energy consumption and improve the environment still further. These are 'occupancy' and 'demand dependent fan speed'. The same laptop software enables air volumes to be slowly and imperceptibly reduced when thermal loads are low. The software also allows the unit to react to an unoccupied area by relaxing the heating and cooling set points.




This means that when the first person enters, say, a meeting room, the fan coil snaps into occupied/normal mode. From then on the fan speeds track the demand and allow sufficient air to be supplied to meet the precise requirement and no more.

In practice this means that for most of the time, the unit uses far less energy and generates less noise and will, as a result, have a longer operational life. Conversely, when the room becomes unoccupied, the fan coil snaps back and maintains the room in a holding condition.

Matrix II retains all these features but has two major extra facilities. First, instead of adjusting fan speeds, the required air volume per duct run is typed directly, as a value, into the software. If, for example, the design specification calls for 75 litres per second, then precisely that is entered. Once installed, each fan coil, irrespective of the external static pressure in the ductwork, will establish the correct air volume along each duct. Subtle variations between ductwork runs do not matter because fans will self compensate.

The second new feature is self setting maximum water flow rates. This enables the design water flow rates for both heating and cooling loads to be entered into the software along with the air volumes. When installed, the fan coil control valve, a two-port pressure independent unit, modulates between 0% (closed) and 100% (design water flow rate) and no further.

Vital difference

This procedure may appear similar to other valves of comparable style but the vital difference is that the water flow rate can be adjusted at any time through the software or the BMS, without the need for access to the fan coil itself. Flow rates are set with an accuracy of ±2% on the maximum flow rate, and sometimes even closer.

Matrix II, therefore, removes the need for volume control dampers in the ductwork system and now the flow setting devices, double regulating valves or similar, in the hydraulic system.
In practice, a Matrix II fan coil unit will 'self set' its own air flow rates on site, as well as air volume balancing its own duct runs and modulating its own water flow up to, but not beyond, design maximum.

This is the reason commissioning a Matrix II is a checking rather than a setting process. Further, after a fit out or similar, any value within the control strategy can be altered and transmitted to either a single fan coil or a group of fan coils, or the entire building system can be re-set at will through the software alone; it takes seconds.

The software and Matrix features do not depend upon the BMS having been installed, although the features can be integrated into any BMS should this be desired.

Ability regularly run functional demonstrations at the company's in-house test facility. It is only when customers actually witness Matrix II operating in a real installation they appreciate the vast potential the product offers to improve the environment while reducing cost, installation time and energy consumption. These demonstrations are ongoing and interested parties should contact the factory.