the sun onto a single vacuum absorber tube supported above the array. The tube contains water at a pressure of 16 bar. The high pressure enables the water to be heated by the sun to a temperature of to 200C without turning to steam. The super-heated water is stored in
a buffer tank before being pumped to a double-effect lithium bromide absorption chiller. Here it is used to drive water from the diluted lithium bromide solution as part of the absorption cooling process. The chiller produces water cooled to 6C. To enable the solar-powered chiller’s
The mini-stadium aims to show how conditions can be kept to mild temperatures for players on the pitch with the use of sustainable technologies
on the pitch. During the day the pitch and stands are protected from the sun beneath a giant domed roof canopy. This is formed from hundreds of triangular, amour-like scales of PVC material stretched over a steel frame. The PVC has a low-emissivity coating to reduce re-radiation of the heat. The scales are arranged to form a series of shaded, north-facing openings to let heat escape from beneath the roof while allowing reflected daylight to bounce into the space. Beneath the canopy a blanket of pillows made of ETFE – a transparent polymer sheeting – provide thermal insulation to limit the amount of heat radiated by the roof. This helps to ensure that conditions remain within ASHRAE comfort standards for the spectators. In the run-up to a match the roof will
remain closed throughout the day to shelter the stadium from the burning sun and enable the stadium’s cooling system to cool the interior effectively. FIFA rules state that World Cup games should not be played under cover. The Showcase stadium’s roof is divided into two semi-circular halves: a fixed, western section and a movable eastern section, mounted on tracks. To open the roof, the eastern half is rotated until it nestles beneath the fixed section. Matches will be played in the evening, so the fixed section is designed to shield the pitch from late-afternoon sunlight and to offer some protection against strong desert winds. Arup Associates has turned the country’s
This zero carbon, environmentally friendly, mini-stadium demonstrates that it is possible to provide comfort for football matches in the heat of the desert
36 CIBSE Journal July 2011
climate to its advantage when it comes to keeping the stadium, players and spectators cool. Adjacent to the stadium is a giant solar farm, covering an area roughly twice that of the stadium itself. The farm contains a giant linear Fresnel collector formed from 44 strips of flat-plate mirrors. These 32m-long mirrors are motorised so that they can rotate around a single axis to track the sun. The mirrors are arranged into four groups of 11. Each group of mirrors is angled to focus
output to be stored until it is needed in the evening, the chilled water is piped to a 3.5m diameter, 12m long cylindrical storage tank buried below ground adjacent to the stadium. The water-filled tank is packed with eutectic blocks, measuring roughly 300 x 200 x 25mm. The blocks are filled with a material which freezes at 6C. The cooling is stored as latent energy in the material as it changes phase from liquid to a solid. When a match is under way, cooling energy is released back to the system as it returns to its liquid form.
Arup has turned the country’s climate to its advantage when it comes to keeping the stadium, players and spectators cool
Once the store is fully charged it can
provide up to five hours of cooling. ‘The really good thing about this solution is that once the tank is charged, the chillers can stop but you’ve still got cooling,’ says Beaven. Should the solar system fail completely, the designers have taken no chances and installed a conventional, standby chiller. From the storage tank, the chilled water
circuit connects to two air handling units (AHUs). One AHU serves the back of house areas with chilled, dehumidified air; the other serves the pitch area through grilles beneath the spectators’ seats. The pitch is surrounded with a concrete structure to add to the stadium’s thermal mass, to mitigate heat gain from spectators and floodlighting. As the cold air descends to the pitch it forms a reservoir of cooled air in the bowl of the stadium to keep the players cool. The biggest threat to the design is the
wind. On cool days the cold air is held within the stadium bowl. However, on windy days there are concerns that the desert winds
www.cibsejournal.com
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68