WORDS: Henk Lustig PHOTOS: Arno Pieters and Pieter Vosloo
The Tshwane University of Technology’s architecture department is well established as one of the foremost schools of architecture in the southern hemisphere. The original building that housed the department had become dated and impractical. A new building has now been erected – a building that boasts a fresh approach to neglected principles, while keeping aesthetics and environmental impact close to heart.
The new architectural department consists of three sections: a sculptural auditorium situated on the western side, a southern wing with offices and studio spaces, and a northern wing with a material lab, model building facilities and studio space. The wings run in thin, multi-leveled halls from east to west, allowing for maximum exposure to the northern sun. Windows make up the walls along the northern side which is enclosed by removable louvers. The louvers are individually slotted into ribs that rise up from the ground. Each louver can be adjusted according to the sun, a process that will be done manually twice a year in March and September. The louvers also act as light shells that reflect light into the building without using power. Students perform all necessary adjustments to these louvers over two days as a part of their curriculum. This systems management approach over mechanical solution allows for minimal environmental impact while learners gain a first-hand understanding of seasonal climatic effects on buildings. All of the windows along both lengths are pivot windows, a window system that is no longer in production. They were made specifically for the project. The windows can be fully opened which allows for optimal airflow without the use of air conditioning systems. The slant of the windows also stops any rainfall from entering through them when they are opened.
The south and western side of the building is fitted with a mist system to cool the air, subsequently creating a microclimate. The sprayers are fueled by rainwater collected in reservoirs from the roof of the building and pumped by a motor that runs off of solar panels. The exterior northern side of the building encloses a paved courtyard; an area designed to collect heat from the sun. This artificial imbalance in temperature results in a cyclic airflow from south to north that can be regulated through opening and closing of selected windows.
The true gem in the building’s crown is its auditorium. The ceiling is high and lofty, the seating, functional and stylized. It is also the only auditorium in the country that has no HVAC system installed. On the western wall there is an opening just above ground level that leads into an open expanse under the seating known as a plenum. The western wall of the auditorium is angled at 30 degrees to north and slanted at 5 degrees to minimize solar heat gain. A Set of mist sprays cools down the outside air at low level. . The roof of the auditorium has been fitted with 32 whirlybird extraction units. When the auditorium is full, the body heat generated by the students warms the air in the room, causing it to rise upward, setting in motion the whirlybirds. This creates a vacuum in the hall that draws cooled air from the outside of the building, into the plenum and out past the ankles of the seated students into the main hall. The top of the rear wall has two large windows, fitted with solar fins, to allow manual control of light and heat into the space. Three 600mm diameter flues rise at the back of the space, close to the ceiling, where warm air is harvested in winter time and recirculated. The whirlybirds are then closed off with dampers.
The entire southern façade boasts a radiator in the form of an adjustable louver placed in front of a winding copper pipe that is connected to the solar panels on the roof. In winter hot water is pumped down from the roof, effectively turning the entire wall into a radiator-style heater. Once the louvers are opened, air blows over the heated pipes, pushing heated air through the building. All of the windows on the southern façade have double-glazing to conserve gathered heat. The indoor balcony allows for heated air to rise freely and be drawn out of the top of the building. The indoor balconies create a vertical studio that creates a psychological link between students of different years by allowing immediate, open communication. The link between the two wings of the building acts as a solar chimney, with the bathrooms on the eastern side that act as a barrier to the harsh eastern sun. All of the hot air generated in the lavatories escapes through the solar chimney directly above it. The solar chimney has a saw tooth roof that allows for maximum airflow out whilst preventing any rainfall from entering the building.
The top floor makes use of a Trombe wall to generate and regulate heat. It is effectively a small ‘greenhouse’ fixed to the outside of the eastern and western walls, which trap the heat. This hot air is then circulated into the building in the winter. In the summer, vents in the ‘greenhouse’ are opened, allowing the hot air to escape. During the night, this ‘greenhouse’ cools down first, and when the temperature inside the Trombe wall is lower than the temperature on the inside, the fans start to circulate the air once again. This then ‘flushes’ the building with cool air during the night. From the inside the feature is visible through a number of circular openings in the wall. The design is meant for a northern wall but due to space limitations it has been installed on the eastern and western sides of the building.
In order to keep pathways clear of cabling, electricity is brought in on a series of cable trays that hang from the ceiling as opposed to running through a power skirting. These trays have input panels and hooks from which electrical cables are hung, freeing up floor space and preventing people from tripping. This system also allows for optimal flexibility as far as adjustable workspaces are concerned. Workspaces can be further customised by making use of room dividers specifically designed for the building and based on a scaffolding system, which are wedged in place between floor and soffit, and added to as required.
Arno Pieters, of Crafford and Crafford architects, has this to say about their latest creation: “We believe that the whole approach to ‘green buildings’ and sustainable design has become a platform for gimmicks and expensive technologies that are not always necessary. We wanted a straightforward building, using age-old design techniques rather than fancy new age equipment, with minimum maintenance, but maximum adaptability. The building itself is didactic, it is a lab, an experiment that has only just begun.”