星空传媒

The judges were unanimous when they chose the Lewis Glucksman Gallery in Cork as the winner of this year鈥檚 星空传媒 Services Award for projects under 拢20m. In their summation they commented that it was 鈥渁n outstanding, unusual project executed in a creative fashion鈥� 鈥� and this despite the fact that it was delivered on a very tight budget.

The cost of procuring the building was set at 陇12m (拢8.3m), with 陇8.5-9m (拢5.9-6.2m) earmarked for construction. 鈥淚t was a constraint that was never relaxed despite the architectural vision for the project,鈥� says John Burgess, associate with Arup and engineer in charge of the project鈥檚 M&E design.

O鈥橠onnell & Tuomey is the architect behind the scheme and had the job of squeezing the 2350 m2 building onto a site that is bordered by the river Lee and a large number of mature trees. In response to this the architect kept the footprint of the building to the area of the two tennis courts it replaces and built tall. The building鈥檚 sev en floors house four exhibition spaces, multifunction rooms, lecture facilities, a cafe and a basement gallery store.

The exhibition spaces were central to the brief and provide public galleries for University College Cork鈥檚 modern art collection, as well as travelling and special exhibitions.

Throughout the design and construction the architect stuck religiously to its vision, Burgess says, and delivering that vision required some real ingenuity from the services engineers.

The original client brief asked for a windowless internal gallery held under close control conditions, with naturally ventilated wrap-around perimeter galleries. However, Burgess says the building form was so unusual it would have cost more to naturally ventilate the spaces than to provide mechanical cooling. 鈥淲e said we could use displacement ventilation, and although we鈥檙e not naturally ventilating it per se it does mean we have a means of controlling conditions inside.鈥� When relative humidity control is not required, the ventilation system maximises the opportunity for free cooling as the minimum air supply temperature is 19掳C.

To reduce the building鈥檚 environmental footprint the displacement system that has been adopted throughout the building is coupled with a ground energy thermal transfer system (GETTS). This has been developed to minimise the energy needed for heating, cooling and humidity control and exploits the water in the alluvial gravel deposits beneath the site (see box, over the page).

The building uses cast in situ concrete for the basement to second floor, above which it reverts to a steel frame with composite walls. Providing plantrooms, routes and risers has meant going into normally out of bounds zones. The only straight vertical line through the building is the lift shaft and squeezed into the single central riser alongside this is the electrical riser, low temper- E E ature hot water, chilled water, gas supply and kitchen extract. 鈥淭he architect wanted to maximise the public space and maintain a clean, uncluttered look,鈥� says Burgess. 鈥淭he knock on effect was that routing the services was very difficult and time consuming.鈥�

On top of this, all systems have been designed to minimise noise intrusion to the gallery spaces and this has resulted in larger, low velocity duct distribution systems and acoustic attenuation on all plant, including the use of specially lined drainage systems. 鈥淲e sat down early on in the design with the structural engineers to coordinate how we would route the ductwork through the building structure, as well as co-ordinating with the concrete contractor, as most of the electrical services are routed in conduit embedded into the concrete floor slabs.鈥�

The four interlocking exhibition spaces vary in size and are staggered over the building鈥檚 three upper floors. Air is supplied discreetly at low level, mainly from bespoke window floor boxes, but also through wooden floor grilles, slots built into the stair risers and storage cupboard pedestals. Most of the ductwork is brought down inside the composite walls, occupying the 200 mm air gap, and is then brought along in the spaces between the floor and wall joists to serve the gallery spaces. Return air is taken out through shadow gaps between the ceiling and walls.

Given the volume of the gallery spaces, ventilation rates weren鈥檛 a driving factor; the air-handling units provide three air changes an hour rather than six. Even so, specially built units had to be used to fit the available space. The AHUs that serve the E E wrap-around galleries are all housed in the fifth floor plantroom, while the AHU serving the central close control gallery is split in two, with supply and return sections housed in separate plant spaces. A third AHU supplies the basement gallery store. This is a large unit given its 100 litre/s supply mainly due to the carbon filters, panel bag filters, heating, cooling and dehumidification plant it contains.

The heating, ventilation and air-conditioning systems are controlled through an energy management system using triple redundancy temperature and humidity control for each of the gallery spaces, playing an important role in providing user flexibility.

Early predictions by Arup showed that by using the GETTS system, energy consumption for the assumed hours of occupation would be around 400,000 kWhr, or 175 kWhr/m2/annum. This is about 25% of the levels expected from a conventional chiller and boiler heating system, amounting to a reduction in CO2 emissions of 256 tonnes a year (from 351 to 95).

Since the building was opened in October last year energy consumption has been monitored, but so far it is higher than predicted. 鈥淲e鈥檝e been monitoring energy use and we鈥檙e not meeting those targets, mainly because the university is operating the wrap-around galleries in dehumidification mode,鈥� says Burgess. 鈥淭he initial brief was only for close control in the one internal gallery but because the gallery now has the option of a better quality environment in the wrap-around galleries it鈥檚 using it and consuming more energy than it should. We need to get the curators to relax the conditions when there isn鈥檛 an exhibition on.鈥�

Burgess is also hoping to reduce energy consumption further by switching off the condensing gas boilers. These provide back-up should the GETTS system fail and also supply high temperature hot water for the trench heaters at the base of the showcase windows and the radiant panels used to offset the risk of condensation. 鈥淲e鈥檙e going to try it next year and see what happens, if we do have a problem with condensation we can simply turn them back on, but we could virtually eliminate all of our gas consumption.鈥�

Apart from this, the building is living up to expectations. For the university, the gallery represents a breakthrough in the standard of new buildings it can expect, capturing the imagination of the public while also achieving the triple bottom line of sustainable design. And the demanding architectural and aesthetic objectives have been met, despite the highly serviced nature of the building. For Fiona Carney, director of the gallery, it is a huge success. 鈥淚t been delivered within the budget of 陇12m, but another zero could be added to that number and it would not look out of place.鈥�