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Home / NEWS / Super-talls are more energy-efficient, says Smith


Super-talls are more energy-efficient, says Smith

by CW Staff on Oct 25, 2011


Adrian Smith from Adrian Smith + Gordon Gill Architecture.
Adrian Smith from Adrian Smith + Gordon Gill Architecture.

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The energy efficiency of a super-tall building is superior to the equivalent number of low-rise buildings, according to Adrian Smith, principal of Adrian Smith + Gordon Gill Architecture (AS+GG).

Smith is the designer of the 1km-high Kingdom Tower in Jeddah. He will be delivering a presentation at the Green Build Congress at The Big 5 2011.

“Building enclosures are reduced when building tall. Imagine that a 400m tower of, let us say, 100 floors will have one ground floor and one roof in addition to all of the walls.

"If you split this into 33 buildings of three floors, you will have to add 33 ground floors and 33 roofs where energy loads will be added. It is pretty clear, when you think about it this way, that the energy efficiency of a super-tall building is superior to the equivalent number of low-rise buildings,” argues Smith.

“And if you did build those 33 low-rise buildings, think of the additional land that would be paved over in the process, and the attendant infrastructure — roads, power grids, water and sewers and so on—that would be necessary to service all of that sprawl. Particularly in terms of land use, building tall makes tremendous sense.”

Smith adds: “There are also many other features of Kingdom Tower that we would consider to be ‘business as usual’, but that definitely serve to reduce the impact on the environment. The performance of the MEP systems results in considerable efficiencies over conventional systems.

“The high-performance exterior wall system, for example, maximises natural lighting while at the same time reducing solar heat gain. It will be feature low-emissivity reflective glass that will reduce heat gain as much as possible, while at the same time providing the panoramic views that building occupants want.

“Where the glass is not needed for viewing, we are planning an insulated ‘shadowbox’ panel that minimises heat gain, and which will have essentially the same thermal performance that a stone panel would.”

Another fascinating feature of Kingdom Tower, and one not normally associated with super-talls, is the use of balconies. “They formed part of our scheme for Kingdom Tower from the beginning, in part because we wanted them to shade a significant portion of the exterior wall, and help reduce the overall energy load. They are, of course, also wonderful amenities for occupants, contributing to the project’s social sustainability.”

Water conservation is a key feature. “We have condensate recovery systems, which in Kingdom Tower will collect about 14 Olympic-size pools of moisture annually that will be recycled for irrigation. We have specified highly-efficient sanitary fittings to reduce water waste.

“In common with other tall buildings, water use in Kingdom Tower will be generally lower, as the water-supply network will have a sophisticated leak-detection system to ensure that all water reaching the building gets used in the building, rather than wasted as non-revenue water.”

Smith says the interior will be finished with paint that contains no VOCs. The building management system will be optimised through continued commissioning to ensure it consistently delivers the most efficient level of performance.

“And from the beginning stages of construction, we will be using materials, such as rebar, with a substantial amount of recycled content.”


FEATURED COMMENT

To say that a super-tall building has only one ground floor and one roof as the basis for energy efficiency makes this a

  6 Comments


Readers' Comments


ARUN .V.DEV (Jan 23, 2013)
AL-KHOBAR
Saudi Arabia

COMMENTS
To say that a super-tall building has only one ground floor and one roof as the basis for energy efficiency makes this architect look particularly naive. A tapered building design, generally necessary for tall buildings for mass and stability reasons, means that upper floors have a very high external side surface area to floor space ratio, so not only are they inefficient, the amount of additional roof area in shorter buildings becomes dwarfed by the additional side area per floor space added. He is also very disingenuous to suggest that the comparison is a 100-floor building with 33 3-floor buildings. Why did he not suggest 10 10-floor buildings? Or 4 25-floor buildings? And of course taking into account the tapered design, the number of floors is not actually an intelligent comparison in the first place. The supposed ground/roof argument fades very quickly even applying basic maths. And as other commenters have correctly pointed out, both the construction and operational energy bases grow with height. I am sure there is a "sweet spot" that could be calculated with some rigorous life-cycle analysis to determine the optimal height, but clearly Mr Smith has not presented (nor I suspect bothered to conduct) such analysis

Nick (Nov 30, 2011)
London
United Kingdom

Shape plays a part too
To say that a super-tall building has only one ground floor and one roof as the basis for energy efficiency makes this architect look particularly naive. A tapered building design, generally necessary for tall buildings for mass and stability reasons, means that upper floors have a very high external side surface area to floor space ratio, so not only are they inefficient, the amount of additional roof area in shorter buildings becomes dwarfed by the additional side area per floor space added. He is also very disingenuous to suggest that the comparison is a 100-floor building with 33 3-floor buildings. Why did he not suggest 10 10-floor buildings? Or 4 25-floor buildings? And of course taking into account the tapered design, the number of floors is not actually an intelligent comparison in the first place. The supposed ground/roof argument fades very quickly even applying basic maths. And as other commenters have correctly pointed out, both the construction and operational energy bases grow with height. I am sure there is a "sweet spot" that could be calculated with some rigorous life-cycle analysis to determine the optimal height, but clearly Mr Smith has not presented (nor I suspect bothered to conduct) such analysis.

Rakesh Gupta (Oct 28, 2011)
Doha
Qatar

Super Tall Buildings
Towers or Super Tall buildings generally require more Steel/Concrete for the structure as the buildings have to withstand higher wind pressure in addition to more equipment loads as well as the weight of domestic and fire water tanks on the upper floors. In addition to above additional costs, considerable floor space is lost due to service floors and the safety requirements. Multi level Car parking is another big cost. For the same design criteria, the costs and energy requirements for tall buildings is generally higher than low rise buildings.

Jim (Oct 27, 2011)
New York
USA

Comments below
As a building professional, I tend to believe Martin's arguments on this one. So much of a supertall building's materials are devoted to structure and so much energy will be devoted to elevators that it cannot be more sustainable than smaller buildings.

Robert (Oct 27, 2011)
Dubai

Comment above
I'd suggest that Smith has a far greater depth of knowledge over supertall construction and the calculations involved than Mr Denholm.

Martin Denholm (Oct 26, 2011)
Washington, DC
USA

sustainability of super tall buildings
Physics does not support the contention that super tall buildings will be more energy efficient. Moving people and water up into a super tall structure will requuire more pumping energy and a lot more elevator energy. All the other sustainability issues also work against the super tall building. Those lower roofs can all be green, and that smaller higher roof will probably not be. The energy to build the structure will also be greater for the same reason plus the need for more bracing and elaborate structural systems that require more energy for fabrication. Natural ventilation strategies can work on shorter structures that are not available for the super tall. In other words the question of energy efficiency and sustainability is much more than a calculation of surface area and roof. area.


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