Floor air conditioners can adapt to buildings of all shapes, sizes, ages and phases of construction
A major design challenge for refurbishment projects is integrating high-specification heating and cooling into buildings that were designed long before the air conditioning of commercial buildings became a reality. In the UK in particular, we have a large number of older buildings in need of modernization or refurbishment. Often times, developers will pull these buildings back to the core, adding modern building materials and facades to improve aesthetics, but the original floor slab and structure will be retained. These structures can present a number of challenges in terms of height and creating available space to incorporate essential building technologies required to meet the changing needs of the rented workspace. This article takes a closer look at these challenges and the application of underfloor air conditioning as a solution for heating and cooling these buildings.
Briefly explaining how the plenum air conditioning system works, fully conditioned air is fed into the underfloor plenum from zonal downflow units (CAMs). The supply air is then introduced into the room via floor-recessed fan clamps known as Fantiles. The used return air can be returned to the CAM for overhaul either under the ground or at a high level, depending on the configuration of the CAM. The equipment is modular and flexible, allowing easy adaptation and future change.
Using the plenum under a raised access floor as a ventilation duct is an obvious way to save height. For example, the cavity under the floor is typically in the range of 150 to 200 mm. A ceiling-based air conditioning system typically requires a cavity of 600 to 700 mm, which increases the total space required for services to 750 to 900 mm. By using an underfloor system with underfloor supply and underfloor return, ceiling ducts and lateral pipelines can be practically eliminated. A floor cavity of only 250-300mm is required to accommodate both the wiring and the recessed fan connectors, which in this case equates to an increased headroom of 200-400mm. If the height from plate to plate is severely limited, a slim fan clamp assembly can be used, which only requires a 180 mm deep floor chamber. It is easy to see whether such systems are suitable for the renovation of older building stocks, which typically have lower ceiling heights compared to newer buildings.
The iconic Tricorn House building in Birmingham with its unusual floor slab shape was completely renovated by the Commercial Estates Group over a period of twelve years. Originally, a floor air conditioner was specified as an option that would cool the interior of any floor area in space while maximizing headroom with a restrictive 2.8 m height to the underside of the panel. In the twelve years the system has proven to be adaptable and flexible for the building with several tenants and can easily meet the increasing demands on the cooling load due to higher density and demand from the occupants. Another key feature was the addition of fresh air units that introduce untreated fresh air into the CAM drainage units at floor level, significantly reducing the climbing and maintenance requirements for the plant room.
Developer Allied London specified underfloor air conditioning for two other buildings that were extensively renovated: 20 Cannon Street near St. Paul’s Cathedral and 28 Savile Row in prestigious Mayfair.
On Cannon Street, the 1960s building had very limited space for structural height, and retrofitting a fan coil, VAV, or split system would have required a ceiling void of up to 450mm, an option that simply wasn’t was feasible. The floor air conditioning was adopted, and as a result, the recommended ceiling height of 2.5 m could be achieved, which contributed to the creation of modern, high-quality office space.
The building has been empty since 2008, but as evidence of the project, it was fully pre-leased as the main building to a corporate client at the time of completion.
At 28 Savile Row, an 18th century building that was originally part of the Burlington Estate, Allied London began another major renovation that included a full internal expansion of the core, demolition of structural partitions, removal of redundant mechanical and electrical Services and facilities included. as well as complete removal and replacement of the facade.
Floor air conditioning was installed on each of the six floors with one zone per floor and, as on Cannon Street, slim EC fan connectors were specified to fit into the shallow 180mm floor cavity.
Additional space and energy-saving features of this renovation were the installation of two-pipe heat pumps on external platforms next to each floor, so that no central system was required. The heat pumps were fully integrated and controlled in the air conditioning system.
The projects above are just two examples of how underfloor systems can adapt to buildings of all shapes, sizes, ages and phases of construction. Other recent projects that have introduced underground technology to overcome structural and height restrictions include: 17 Devonshire Square, with slab-to-slab restrictions; 33 Glasshouse Street, the picture clearly shows the standing beams falling under the full-height windows; 20 Soho Square, a classic core, floor, and shell scheme; and the remarkable Here East project at Queen Elizabeth Olympic Park.
Plenum air conditioning systems are not considered mainstream like ceiling systems and are therefore often overlooked as an unknown quantity by designers and engineers. Floor air conditioning systems are demonstrably able to adapt all buildings, adapt to the changed use of space and combine this with modularity and simple Cat B equipment. The technology offers future-proof solutions for challenging projects.
Please note: this is a commercial profile
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