Multi-split air conditioning systems

The store is served by multi-split air conditioning, with multiple indoor units running from shared external condensing units.

Multi-split suits this unit for two reasons. The first is load. An open plan retail floor with full height glazing on one elevation gains a significant amount of solar heat through the day, whilst passenger numbers rise and fall sharply around departure waves. Cooling demand is never steady.

The second is layout. Rather than one central plant serving the whole floor, indoor units are distributed across the space and positioned to suit the zones beneath them, so conditions can be held consistently from the entrance through to the payment and service area at the rear.

Running several indoor units from shared external plant also keeps the external plant footprint down, which matters in a terminal where space and access are both restricted.

Heat recovery ventilation

Fresh air is provided by a heat recovery ventilation system, which supplies outside air to the store whilst recovering heat from the air being extracted.

A retail unit of this footprint carries high occupancy for sustained periods, and the required fresh air rates are set by that occupancy rather than by floor area alone. Meeting them without heat recovery means continuously conditioning a large volume of outside air, which carries a running cost every hour the store is open.

The heat recovery unit transfers heat between the extract and supply air streams, so the store gets the air changes it needs without the corresponding energy penalty. It also takes load off the air conditioning system, which is working hard already against solar gain and occupancy.

Ductwork distribution is run at high level within the exposed services ceiling, coordinated with the lighting, sprinklers and retail fit out so the finished space reads as intended.

Controls system

The air conditioning and ventilation systems are brought together under a single controls system covering the store.

Controls are what make the individual plant items work as one building. They set the operating strategy, sequence the air conditioning and ventilation so the two are not working against each other, hold conditions across the floor, and allow the store to run to trading hours rather than around the clock.

In a terminal environment that matters more than usual. Trading patterns follow the flight schedule, not a standard high street day, and an early departure wave puts the store under load long before a typical retail unit would be open. The controls allow the systems to respond to that pattern rather than run at a fixed output through it.

For the retailer, it means a simple interface and a store that holds its conditions without daily intervention from staff who have a shop to run.

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