Underfloor air conditioning system used to boost sustainability at 1930s former clothing factory redevelopment

An underfloor air conditioning system supplied by AET Flexible Space has contributed to the top sustainability credentials of the redevelopment of a 1930s warehouse and former clothing factory in Clerkenwell, London.

Completed in June 2020, the high-end refurbishment and extension has transformed its interior space into six floors of premium, light, airy, and flexible workspace. Harella House has received a BREEAM ‘Excellent’ rating, and it is estimated that the refurbished building achieves a 47 per cent reduction in carbon emissions.

Its history as a warehouse and factory meant that Harella House boasted stunning high ceilings and crittal windows. However, years of internal redesigns had obscured many of the building’s best original features. These have now been stripped back to reveal riveted steel columns, perimeter brickwork piers and concrete encased beams.

Reducing the building’s energy consumption and carbon emissions were key considerations for this project, and AET Flexible Space’s underfloor air conditioning system was selected for its low environmental impact and high efficiency. The ceiling heights and original windows were key features to be preserved during the refurbishment, and one of the main advantages of AET’s underfloor air conditioning system is that all equipment is installed beneath the existing raised access floor, negating the need for high level services and suspended ceilings.

Having worked closely with M&E consultants, Elementa Consulting, AET’s CAM-C (floor supply, low level return) system was identified as the most suitable AC solution and subsequently specified. During the refurbishment work’s AET’s CAM-V system (floor supply, high level return) was then specified to serve the newly included mezzanine level on the fourth-floor where AET’s slim line TU350 Fantile units were installed helping to reduce the height of the raised access floor and maximise floor to ceiling heights.

Throughout the building, chilled and low-pressure hot water is fed to each of the 14 CAM units which in turn produce cool and warm air as and when required. The floor void is divided into supply and return air channels. Conditioned air is introduced into the space by the, floor recessed, Fantile™ units with spent, room air, drawn back to the CAM unit via passive, return grilles, which are also installed within the raised access floor. Fresh air is ducted into the return air path from a centralised air handling unit where it mixes with the room air, filtered and reconditioned.

Another key design aspect of the building was the need to be able to offer a flexible working environment which was another reason why AET’s underfloor air conditioning system was specified. AET’s innovative, plug and play, Fantiles™ units sit within the raised access floor and can easily be repositioned within minutes, to suit ever changing office layouts. Thus giving the occupants of Harella House complete control over how they use the office space without the costs associated with repositioning fixed, ceiling-based systems.