Occupying 55 000m² while also offering a mixed-use city usage office block and 450 car parking spaces, The Eastgate Centre Project, is described by various journals and architecture magazines as “a seminal project”.
It was designed by leading designer and architect Mick Pearce, who in his design of the centre replicated how termites construct their nests to ventilate, cool and heat through natural means. The termites’ structures are reportedly able to maintain the temperature inside the nest to within one degree of 31°C, day and night, even when the external temperature varies between 3°C and 42°C. They also use only 10% of the energy of a conventional structure of the same size – a feat mimicked in Pearce’s design of the Eastgate shopping centre.
Because artificial air-conditioning systems are high-maintenance, and in Zimbabwe most spare parts have to be imported, this complicates things and results in stretching foreign exchange reserves in the process. But with Pearce’s design all these limitations are immaterial as he has taken care of all of the complications that come with a building of this size and magnitude.
The centre was opened in 1996 on the corner of Robert Mugabe Avenue and Second Street, and over the years it has come to be referred to as “the world’s first building” to make use of high level and sophisticated natural cooling and heating systems.
Wikipedia describes biomimetic architecture as a “contemporary philosophy of architecture that seeks solutions for sustainability in nature… by understanding the rules governing those forms”, those who know say it is a “multi-disciplinary approach to sustainable design that follows a set of principles rather than stylistic codes”.
The Eastgate Centre Project is the epitome of biomimicry in its use of natural cooling and heating systems that use thermal mass and a specific air change schedule that produces high rates of mechanical night cooling, supplemented by smaller rates of passive ventilation during the day to keep air fresh and at the correct temperature.
The ventilation system is reported to have cost one-tenth of a comparable air-conditioned building and uses 35 percent less energy than comparable conventional buildings in Harare.
In addition, fan power requirements are reduced by stack effect ventilation throughout the building, and the buoyancy effect generated by the occupants’ metabolic activities. The ventilation itself costs one tenth of that of a comparable building, saving R43 million in energy costs in the first 5 years alone.
The centre, which is largely made of concrete, has a ventilation system which operates in a similar way. The outside air that is drawn in is either warmed or cooled by the building mass depending on which is hotter – the building concrete or the air. It is then vented into the building’s floors and offices before exiting via chimneys at the top.
The complex also consists of two buildings side by side that are separated by an open space that is covered by glass and open to the local breezes. Customers as well as tenants have also saved on rental fees with rent reported to be 20 percent lower than those of occupants in the surrounding buildings.