CONSTRUCTION
Cool working in hot climates
Andrew Watts of engineering consultant Newtecnic tells Jonathan Newell about a new approach to tall building design to overcome solar heating problems in hot climates
S
et to rise from the banks of the River Tigris in Baghdad, the new headquarters of the Central Bank of Iraq is already creating waves in architectural and construction circles with its innovative
design and its new approach to managing heat and light in the powerful climate of the Middle East. Designed by Zaha Hadid architects, the 170m
high tower will benefit from the technical expertise of Newtecnic, a company whose modern approach has already set it firmly in the list of key engineering companies in the construction industry.
A BLEND OF TRANSPARENCY AND OPACITY The creation of towers as “glass boxes” with toned or solar reactive glazing is a trend that Newtecnic very much wants to buck. With such disadvantages as light attenuation and solar heating effects, such designs have their drawbacks even in moderate climates but in the unremitting climate of the Middle East, these drawbacks become serious flaws. According to Newtecnic, there is the opportunity
to create the means to provide natural lighting where it’s needed without the drawbacks through a combination of glazing, shutters and adaptive air- conditioning. Such glazed areas can be blended with opaque zones on the building facade placed in areas where natural lighting isn’t a requirement. This is exactly the approach the company took with its designs for the Central Bank of Iraq tower.
SOLAR CONTROL PANELS For the glazed areas, the design incorporates solar control panels on the inside of the glass. “Usually, these are fixed and external but in the Central Bank
of Iraq’s case, these are like blinds between the glazing,” explains Watts. This gap which houses the blinds is about
300mm between the outer double glazing and the inner layer of opening panels. “This gap is also used for cooling. Blowing air through it provides another layer of protection against the build-up of heat,” adds Watts. Newtecnic employs computational fluid dynamics
(CFD) analysis to model the building performance in different environmental circumstances and to ensure that the building management system can adequately orchestrate the complex interaction of solar control panel operation, HVAC and lighting in order to maintain the best environment for the occupants while minimising energy consumption.
❱❱ A blend of glass and concrete creates light where it’s needed without subjecting the occupants to the negative effects of solar heating, top; the Central Bank of Iraq’s tower and podium is expected to be under construction during 2020, above
OPAQUE FACADES Not all facades on the building need to be transparent and an important aspect of the tower’s design is the creation of opacity where appropriate, while still allowing the adequate passage of daylight. “The correct design and placement of opaque facades with adequate access to daylight is important to reduce the levels of electrical lighting needed during the day,” says Watts. For the future, Newtecnic sees such facades as
providing more than structural support and opacity. Changes to the composition of the concrete can enable them to be used for absorbing atmospheric carbon. However, such changes aren’t quite on the horizon. “The industry has a century of experience with
concrete so you can’t just change the chemical composition of it without research into its long- term safety,” concludes Watts. EE
June 2018 /// Environmental Engineering /// 27
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