Carbon emission influences choice
State of the art Daikin inverter controlled VRV heat recovery air conditioning is a key component of new building services designed by consultants Foreman Roberts, for the 15 Fetter Lane, EC4, development. Rising phoenix like from its former site, the new complex is among the more imaginative and visually attractive additions to the City’s commercial office stock.
The redevelopment of the site by the British Steel Pension Fund has seen the earlier building stripped back to its shell and rebuilt to Grade A specification, offering 70,000ft2 of open plan office accommodation on nine floors.
Installed by Daikin D1 installers, Breath Air, Cambridge, for mechanical and electrical contractors, EMCOR, Hatfield, the new air conditioning system comprises 33 REYQ VRV heat recovery systems. These supply 220 FXYSM fan coil units, located within the false ceilings on each floor and ducted to linear grilles around the ceiling perimeter and central core of the building. Indoor design temperature is set at 21°C +/- 2°C, summer and winter.
Each floor is divided into three zones, each zone being handled by its own VRV system and when tenanted, its own Daikin I-controller, allowing the landlord to monitor electrical consumption and apportion its costs on an individual tenant basis.
Each floor is also supplied with heat recovery ventilation via five or six Daikin VAM units, also located in the floors’ false ceilings. Tempered fresh air is supplied by these units, which modulate the temperature and humidity of incoming outdoor air to match prevailing indoor conditions. A balance is thereby achieved between indoor and outdoor ambient conditions, minimising the loading imposed on the air conditioning system to cool or heat the incoming air. The high sensible and latent heat reclaim features inherent in VAM units reduce input energy requirements and costs and keep CO2 emissions to a minimum.
Overall VRV and VAM control is provided by a Daikin I-manager located in the ground floor control room, which will, if the central computer crashes, continue its control and management functions for not less than 48 hours.
Key decisions behind the consultants’ choice of VRV air conditioning included the system’s favourable carbon emission readings compared to those of a similar capacity chilled water system, which could not have satisfied Part L regulations on this particular installation. Also, the VRV system’s inherent design and installation flexibility overcame the building’s lack of plant room space.