In February 2013, the building referred to as No.1 Silo received a 6 Star Green Star SA Design rating by the Green Building Council of South Africa (GBCSA). It is only the second building to be awarded a 6 Star Green Star SA rating in South Africa and the first in the Western Cape.

“We have adopted a rigorous approach to green construction and sustainable design principles, and the efficient use of natural and energy resources,” says David Green, chief executive officer of the V&A Waterfront. “The architectural vision and mechanical design of the building ensures optimal indoor environmental quality for occupants to promote health and well-being.”

Sustainable development and green operations are fundamental to the V&A Waterfront’s overall development strategy, adds Rory King of MACE, the project manager and principal agent. Both developer and tenant had the desire, leadership and commitment to achieve a 5 Star rating as announced at the sod turning ceremony in September 2011. The actual rating achieved is the result of everyone involved going the extra mile over the last couple of years, says King.

The client and the core design team visited Australia before the project started and looked at some of the top-end sustainable buildings. Jaco Kemp of Arup, the sustainability and Green Star SA consultant on the project, explains that they sought architectural concepts and engineering solutions that would respond to the environment in an appropriate manner and used the environment to its advantage. “The seawater system is an example of this. Systems were introduced that have a dual purpose, such as the raised floor system that is used for electrical distribution and air conditioning.”

John Abbott, facade engineer of ARUP, says the design of the facade of the building played an important part in achieving the coveted 6 Star rating. The architectural concept called for large areas of glass and for this to be as transparent as possible. The facade was studied using energy and lighting simulations and drawing on the experience of colleagues with other highly transparent buildings in similar climates. The solution has been to use double skin facades on the northeastern and northwestern elevations, which are most vulnerable to solar gain. These facades have an outer skin of clear glass, spaced 700 mm outside the main facade, which is double-glazed for thermal control. Automatically-controlled blinds between the inner and outer skins track the sun as it moves across the building.

One of the more unique green initiatives is the use of seawater from the Atlantic Ocean. Used to reject waste heat from the cooling plant, it allows for significant potable water savings and improves the overall energy efficiency of the building. Smith says the system functions by drawing in seawater from the harbour through a titanium plate heat exchanger system in the basement.

The ventilation system used is able to take maximum advantage of outside air to cool the building in the mild Cape Town weather. Heat pumps are used to heat the building during winter months.

* The full article appears in the August – September 2013 issue.