Under Floor Air Conditioning: what makes our systems different? – AET Flexible Space

Under Floor Air Conditioning: what makes our systems different?

By using the plenum beneath a raised floor as the ventilation zone instead of traditional ceiling based air conditioning, it is possible to eliminate much of the ceiling based duct and pipe work leading to huge savings in construction materials, installation costs, fit out and reconfiguration costs.  Building services traditionally consume a large proportion of a building’s operational energy use, and construction practice often leads to wastage of materials and consequently the embodied energy stored within these materials.  By adopting the AET Flexible Space approach, an amount of this energy can be conserved using modular, pre-engineered equipment, especially the time and energy spent during the construction phase.

Removing the ceiling void can also have a huge impact on the use of internal space within a building.  Duplicating the floor void for cable management and ventilation lends itself to height savings in new build construction and refurbishments alike.  The floor void beneath the raised access floor is usually in the region of 150 – 200mm, and a ceiling based air conditioning system typically requires a void of 600-700mm bringing the total services space requirement to 750-900mm.  By adopting an underfloor system with floor level supply and floor level return, ceiling ductwork and lateral pipework can virtually be eliminated.  A floor void of only 250-300mm is required to accommodate the cabling and fan terminals, equating to increased headroom of 200-400mm in this example.  Where the slab to slab height is severely restricted, a slimline fan terminal which only requires 180mm floor void space can be used.

height saving

In new build construction this height saving can lend to additional lettable space or reduced building height, which in some cases is necessary to achieve planning permission. A tall building in Hong Kong adopted this system and was able to fit in an additional floor for every ten floors constructed due to the height savings created by this concept.  Transfer this across construction and it has been said that it is possible to construct another building with the cost savings realised.  Build ten buildings, get one free!  Undoubtedly attractive to any forward thinking developer.

Plenum based air conditioning can also maximise the floor to ceiling height in refurbishment projects.  In the UK, older building stock often has features such as limited headroom and smaller floor plates making it a challenge for engineers to accommodate the preferred 2.5m headroom using traditional ceiling based air conditioning systems.  Perimeter systems can be considered but this brings the penalty of loss of prime lettable space and also makes it difficult to ventilate internal areas.  Without a minimum floor to ceiling height of around 2.5m letting agents are reluctant to promote commercial space as Grade A accommodation, all important to today’s corporate clients. Testament to this approach is the number of refurbished buildings that have adopted the underfloor concept as a solution to slab to slab height restriction. 28 Savile Row, Tricorn House in Birmingham, 76-88 Wardour Street, Bloomberg at City Gate House in Finsbury Square, No. 1 Cavendish Place, 20 Cannon Street, 196 Deansgate in Manchester, 180 Great Portland Street amongst others in the growing refurbishment market.

The height saving benefits of under floor systems are well proven, but that is not all. Minimising waste and energy consumption is achievable through using modular and flexible equipment that is easy to operate, clean, maintain and re-use. In this way UFAC systems can help architects, developers and clients’ future proof their buildings for the next twenty, thirty or forty years.  The ability to adapt to change of use is all important and as most HVAC systems are fixed, they can easily become unsuitable or even redundant leading to huge wastage and high costs.

Facilities managers are frequently challenged by the pace of office churn, often restricted by fixed, stand-alone services with minimal or no control.  Complaints of draughts and cold feet are common and so many times one sees ceiling diffusers switched off or covered with sticky tape and paper in an attempt to divert air when workers are based in a less than ideal position.  AET Flexible Space systems are modular and adaptable. Plug and play fantiles easily interchange with 600mm raised access floor panels allow fast reconfiguration of office layout and easily accommodating minor changes and major churn.  Equipment features simple yet sophisticated controls for individual users and facilities managers offering superior control of indoor environments compared with traditional ceiling based or wall mounted air conditioning units.

FSS air flow

Fantiles have integrated fatronic controllers allowing users local adjustment of temperature and fan speed to suit personal comfort.  Local adjustment of CAM units by service and maintenance engineers is easy accessed via the flexmatic display mounted on the unit face.  Systems can be now be configured using the latest flexvisor software, allowing remote adjustment and monitoring. Facilities managers can use the flexvisor system to monitor usage and consequently streamline operational efficiency and it also provides a user friendly and cost effective solution to keeping the BMS updated.

It is interesting to note that when users are free to choose their environmental temperature they often choose higher temperatures than engineers design for; as a result considerable savings in operational energy can be made.  A rise in setpoint temperature of 1oC will often reduce energy by as much as 10%. The FM can observe that users are selecting higher setpoints and can re-set the zone units accordingly, enabling fully functional control.

Air conditioning is often the biggest source of complaint in office environments with around 20-30% of workers not happy with their temperature; either being too hot or too cold.  Adaptable, flexible and re-usable HVAC systems are crucial for providing comfortable work space for commercial interiors.  A recent World Green Building Council report demonstrates that the design of an office impacts the health, wellbeing and productivity of its occupants.  Indoor air quality, thermal comfort, noise and interior layouts can all be effected by heating and ventilation design.  Flexible Space systems can eliminate user complaints with the personal local control feature, or by simply relocating fan terminal units to an alternative position.  With worker comfort being directly attributed to productivity and around 90% of business operating costs attributed to staff, the potential impacts of indoor environment design should be a major concern.