Energy efficient skyscraper, the Bank of American tower
The bank of American tower is the fifth tallest building in New York. Located in the avenue between 42nd and 43rd street; and close to Times Square New York, opposite Bryant Park (maybe why it’s called one Bryant Park). It is in the midtown of Manhattan in New York City.
The tower is one of the green towers constructed in the history of man. Little wonder it was the first sky scraper designed to attain a platinum LEED certification. Constructed started in 2004 and ended in 2009, some buildings had to be pulled down on site to make way for the tower’s construction including a 13p-storey hotel and a theatre. Was designed by Architect Richard Cook from Cook + Fox Associates while dream was to construct one of the green skyscrapers in the world.
This tower is not only celebrated for its height but for its energy saving ability as so many energy saving systems were combined in one building thereby making it one of the greenest building ever known to man. Manhattan is a very busy city; transporting materials through the city was quite difficult, so materials used to construct the tower were internally sourced from not more than 800km radius from the site thereby saving on transportation cost.
A total of 22,680 tons of steel over 8000 pounds of crystalline glass windows were used to construct the tower. The structure is 288m high with a 78m spire. The site excavation was manual instead of blasting; this was due to location as subway tunnel was near at 42nd street and another at 6th avenue; and there are all tall buildings and skyscrapers around the area hence not really convenient for blasting. 200ft long, 450ft wide and about a 100ft deep as over 100,098 cubic meters of earth had to be removed from the site by digging which took almost a year of excavation.
The steel beams used for the construction all came from one steel plant. They were made by melting scrap metals that have been collected from old cars, washing machines and dish washers. The steel workers shred them, melt them and remove impurities from the metals. The molten liquid is made to run through molds and transformed into steel beams. They’re tested for strength and durability before they are transported to the one Bryant park site.
The steel beam is not the only thing that leaves the plant. The waste of the steel as well used as a sustainable material. Steel mills produce blast furnace slag, a waste by product that usually is thrown away; but in this case, is used as a key element in the building’s concrete making up 45% of the mix, leading to a drop in the carbon emissions created during concrete production.
“Change from major cement to blast furnace slag saves 56,000 tons of cr2 production. So the concept is work on a really big scale, make little changes, you make big difference” says Richard cook. So 52,000 cubic meters of this concrete slag mix was used in the tower.
The one Bryant Park uses so many energy efficient systems to reduce cost of running the building, from lighting to ventilation to running machines in the building. For ventilation, so many means were adopted to naturally ventilate the building and save on electricity cost. A central open roof atrium running through 190m to the building’s top lets in air to the tower. (This design however forced the core support of the building which is traditionally in the centre to the outer cores of the building). Green life is scattered all over the tower to help release fresh air within the environs. The tower is 80% naturally ventilated, saving 30% on energy use.
More on green construction, one Bryant Park takes in air through the top floors, passes it through a giant air filtration system that cleanses/filters the air; and passes it round the building. The air gets into the building contaminated but gets cleaned up before being passed round the building. And when the air leaves the building, it goes out fresher and cleaner than it came in such that the surrounding air is clean and fresh as well.
Green roof was also adopted at the one Bryant Park. There is a garden of vegetation there at the lower roof area that not only serves as a beauty to behold, but also for cooling the roof, ventilation and storing up water for the building.
This is simple; the roof was designed as a collecting point for every drop of rain that falls on it. When rain hits this roof, it is absorbed by the plants and the excess funnels down to the four tanks placed on different floors in the tower and one in the cellar. These tanks capture and store up the water from the roof which is used in the building; they hold almost 260,000l of water. This process saves over 400,000,000l of water per year and about half a million dollar water bill.
Also in the building cellar at 24m below street surface, sits about 44 cooling tanks, 7570l each. They freeze 227,000kg of ice each and they help keep the building cool by day by filling the entire air conditioner system in the tower and saving on energy.
A state of the art crystalline glass window graced the façade of one Bryant park. This crystalline window lets in natural light while keeping heat away in the tower. That way the tower receives little or no heat from the outside and also natural light keeps the tower illuminated during the day.
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