Controllable FCUs play key role in highest-ever BREEAM rating
Ability Projects Matrix 2 underfloor 4-pipe fan-coil units are playing an important role in the green credentials of the Bristol headquarters of the Environment Agency. Cabot House is the greenest complex of its type in the UK and has received the highest-ever BREEAM rating at the design and procurement stage (85.06%). Relocating to this energy-efficient building is expected to save the agency £180 000 a year in operating and energy costs.
A total of 124 Matrix units have been installed. They are served by chilled water from a ground-source heat pump, boosted by a chiller, and gas-fired boilers. They receive tempered fresh air at 10°C and provide 200 kW of free cooling. All units have top access and self balancing EC/DC motors. They are pre-fitted with BACnet controls and self-balancing PICC valves. All units were delivered to site with water flow rates, air volume and MAC addresses downloaded into their terminal control strategy during manufacture.
Once installed, each fan coil established the correct air volume as a total and along each duct served by that unit — irrespective of the external static pressure of the ductwork system by virtue of self-compensating fans.
When installed, the fan-coil control valve modulates between fully open and fully closed, so water flow rate can be adjusted through the software or BMS — without needing to access the FCU itself. Flow rates are set with an accuracy of ±2% on the maximum flow rate.
Not only is there no need for dampers to control air volume, but there is also no need for flow-regulating devices and double-regulating valves in the hydronic system.
