Africa's Quiet Answer to Global Energy Waste

Inside the bustling city of Zimbabwe, one’s eyes might catch sight of a rare yet unusual sense of building that looks like a modelled combination of both tradition and modernity. Running on a non-conventional cooling system, the building has suppressed years of heat through its natural ventilation mechanics that might be a counterpart to many of the modern industrial buildings that utilise classical air conditioning to survive.

The Eastgate Centre, situated in the Harare region of Zimbabwe, Africa, is one of the most astonishing examples of green engineering and architecture. The seven-story building, devoid of metal casing, large glass windows, and a conventional air system, is a rarity to witness in this mechanical world. In the gruelling heat of Zimbabwe, this building has managed to provide natural cooling to its people using the integrated scientific mechanism of thermal mass, chimneys, and timed airflow that draws in cool air at night and releases it slowly during the day, regulating the temperature inside the establishment. In 1997, the centre won a Certificate of Merit from the International Council of Shopping Centres in New York, making it the first ever building from Africa to receive such an honour.

The development began in 1991, when Mick Pearce, a Zimbabwean architect, was approached by a multinational investment group, Old Mutual, who advocated the later to build a large office and retail complex that functioned entirely on a low-cost, less energy-consuming cooling system. Pearce, being an environmental enthusiast, who has specialised in the field of biomimicry and sustainable energy, embarked on a journey to discover a suitable option that aligns with the given abstract. Through staunch observation and learning, Pearce came across the Termite Mounds surrounding his place, and reflected upon the subsequent studies done on the same by Scientist Martin Lüscher, igniting an idea within the young architect.

In 1961, Swiss scientist, Martin Lüscher, proposed a theory that was widely acclaimed across the globe. Lüscher, having conducted a deep study on the Termite Mounds, concluded that soil habitat created by the small insects produces metabolic heat by themselves, without any external help, which drives the convective air currents, contributing to temperature regulation inside the abode, and exchanging respiratory gases. Although the Swiss scientist’s theory was revoked overtime with experts namely Korb and Linsenmair, exerting the role of the sun in producing heat in the mounds, the later remained dominant overtime. However, it wasn’t until the opening of the Eastgate Centre in 1996 and the subsequent study done by American Biologist, J. Scott, a breakthrough was achieved, with the establishment playing an unknown role towards a greater scientific realisation.

The Termite Mounds build by small eusocial insects named Termites are usually found in the deserted areas of Africa and Australia. These mounds are also classified as ‘Ant Hills’, which can reach up to 7-8 metres in height, giving them an ancient structure. These small hills are made from native soil, termite dung and saliva, used to stick up the structure. Although the habitat might seem like a small protective cocoon with multiple external small pores, the interior imposes a much more complex mechanism.

The Termites, usually assumed, does not live inside these mounds, but rather carry out their routine in the underground, with the mound just acting like a façade. Here, the sun plays an important role. Focusing on J. Scott’s discovery, the mound does not create heat by itself but rather takes it from the sun. The blazing heat from the sun, when shone, is distributed unevenly, where one side of the mound gets more heat while the other does not. This partial heating forms small pressure and eventual temperature differences inside the mound, thus creating a wave like shift in air, that pushes back and forth in a steady rhythm. Furthermore, the air that seeps in and out of the tiny pores of the mound acts like a human lung, carrying fresh air (oxygen) down the underground to the Termites. In return the carbon dioxide produced by these species and their fungal garden gets pushed out once a day through these pores.

Scoots observation was indeed a plot twist to Pearces’ architectural geniuses. The new revelation acted as a pivotal point in proving to the world that Pearce did not just copy-paste the natural method into a much larger setting, but indeed applied his own skill and talent in making the complex run on natural cooling system.

The Eastgate Centre is now a commercial shopping mall, spanning across 5,600 square metres, with multiple floors running various retails and offices. It now stands as an epitome of eco-friendly buildings for Africa and the World, sparking a debate on the ongoing scepticism of whether green and sustainable architecture is an impossibility in today’s world. Eastgate’s cooling system plays an important role in reducing the carbon foot in the growing economy by using only 10% energy required by conventional cooling system. During peak summer heat, that is during 2 or 3 weeks in a year, when the establishment does require the assistance of mechanical cooling, the building only consumes less energy, that is 35% than the average consumption of six conventional buildings, as the passive system does much of the work. This sustainable idea also saves capital, by cutting of additional expenses, instalment and electricity charges, and other needs, saving almost 35 billion dollars.

According to Mike Pearce, sustainable buildings are not a myth; neither is it an impossible idea. He claims that the need for aestheticism and inconsideration of the changing climate, overshadows the green ideas that exists within one’s surroundings. The architect reflects on how through proper identification of one's prevailing environment and thorough analysis of their geography and climate conditions, one can curate the dream of building eco-friendly buildings.

References:

. . .