04 December 2019

The first building to be completed in the mixed-use
Irene Link precinct in Centurion, the Barloworld Automotive and Logistics head
office has been awarded a five-star Green Star SA Design Rating v1.1. In
contrast to Barloworld’s previous offices, the building design incorporates a
flexible, open plan work environment.

“Resource efficiency was a major consideration for
both the owners and tenant,” says Simon van Helsdingen, property development
manager at Abland – a co-owner of Irene Link.

“During the past three years, the Centurion and
Irene areas have experienced regular water interruptions. And, in keeping with
best green building practice worldwide, passive energy design and energy
efficient mechanical systems were required from the outset. The inclusion of
sustainability features meant that we could target a five-star rating during
the design process, as opposed to the initially anticipated four-star rating.”

The 5,860-m2 building accommodates meeting rooms, a gym, a
coffee shop and cyclist facilities for staff and visitors, among other
amenities and is enclosed in a highly transparent envelope that gives access to
views over the surrounding urban context. P.W. Hattingh, project architect at Nsika
Architecture & Design, says, “From the inception of the project, the design
team and developers were like-minded that this project would try to achieve a
high level of energy efficiency that will benefit the end-user. Best practice
principals such as effective building envelope design, efficient energy use and
good indoor environmental quality, were paired with commercially effective
design and a viable implementation strategy.”

The concept focused on creating a simple floor
plate form allowing for a high rentable ratio efficiency so that resources
could be channelled into a strongly aesthetic envelope. “The superstructure, as
well as the choice of façade system and glazing type, were major design
consideration,” Hattingh explains. “The idea was to create a permeable glass
envelope that would sit lightly on a naturally ventilated basement. Time was
spent to optimise the structural design in relation to the building material
weight, and to create a good glazed-to-solid façade ratio. This allowed for a
market-related structural design on very difficult soil conditions while also
achieving optimal natural internal lighting quality with ample external views.”

Both the northern and western facades are double-glazed to improve internal
thermal conditions and address acoustic challenges arising from the adjacent
highway. With a ratio of more than 80:20 between glass and solid façades,
several shading design options were investigated. A vertical aerofoil louvre
fin structure was chosen to wrap around 42% of the building’s eastern and
northern envelope. The louvres act as a ‘permeable jacket’ to keep the building
cool in summer and warm in winter. This is achieved by optimising the aerofoil
fin spacing and angle of the fins for each façade orientation.

Due to the recent water
interruptions, it was decided from the outset to minimise water use in the
building and to provide effective and safe back-up water supply. Dash Coville,
sustainable building consultant at Solid Green, explains, “The building makes
use of water-efficient sanitary-ware fittings as well as water-wise landscaping
and irrigation to support the water consumption reduction strategy. A rainwater
storage and filtration system was also introduced into the building. The system
collects rainwater from the roof and purifies it to a potable level for use
throughout the building. These initiatives have led to a major reduction in
municipal potable water consumption.”

In terms of energy efficiencies, a large 120kW photovoltaic system was designed
by Barloworld Power. The system is expected to reduce the building’s annual
energy consumption by 200MWh. In addition, 100% of the building’s light
fittings are LED, which are connected to motion sensors.

A thermal energy storage (TES) system, which enables a levelling out and reduction of the building’s peak energy demand, has also been incorporated into the building’s design. This is achieved by ‘charging’ thermal storage tanks containing glycol-water during off-peak periods when electricity is cheaper and the country’s energy demand is low. During normal operating conditions, the charged TES tanks then supply additional cooling energy to the building, reducing the municipal energy demand. This process reduces the designed HVAC system’s full load by up to 50%.

Energy and water sub-metering have been employed, which will enable the building to be effectively managed and the outcomes of the implemented sustainable initiatives realised. The meters are connected to a system which presents live data on a visual display, which is located in the reception area of the building and supplies real-time consumption information to building users and visitors.

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