Sustainable schools in Zambia and Uganda
Promoting Equality in African Schools (PEAS) builds schools in rural areas of Africa to provide children with access to education. Orkidstudio had worked with PEAS to design and build a number of schools in Africa, but they suffered from a lack of daylight and overheating issues. Looking to develop the next generation of their design, Orkidstudio approached Atelier Ten for environmental design and building services engineering advice. AKTII were part of the team, providing advice on structural engineering.
The existing design of the schools had prioritised minimising solar gains over letting in natural daylight, resulting in an over-reliance on electric lighting – which is expensive, and not always reliable. The lack of openings for natural ventilation also caused overheating and a build-up of carbon dioxide, without a means of releasing heat gains and air pollution built up over the day.
With these issues in mind, James Lacy-Smith, Paul Vincent and Ivan Jovanovic analysed sites in Lusaka, Zambia and Kampala, Uganda, and provided environmental and engineering advice to design cost-effective, healthy and sustainable school models.
Our environmental designers recommended using low-emission roof materials and paints, combined with suspended pleated bamboo panels to minimise any discomfort from radiant heating given off by the ceilings. These panels would also improve the acoustic quality of the teaching space.
For sites in Lusaka, our team recommended east and west facades were shortened to minimise the need for solar control. Wind comes from the east-northeast or east directions, in a predictably dominant way, so ventilation openings can face along this axis to harness effective cross ventilation. Designing for the stack effect will be useful to purge heat gains in the warm and wet season, when wind velocities are lower.
In Kampala, there is a more dramatic diurnal temperature range available year-round, which will lend itself well to exposed thermal pass coupled with nighttime heat purging using natural ventilation. While all facades will need shading at various times of year, the west façade is subject to highest solar radiation intensity coincident with high outdoor air temperatures. Keeping east / west facades short would minimise the need for solar control. Wind predominately comes from the south, so natural ventilation openings should align north / south to enable effective cross ventilation. Wind velocities are usually low, so designs should make use of the stack effect and buoyancy will drive natural ventilation more effectively.
Our engineers, led by Paul Vincent, provided recommendations on public health facilities, with options such as sustainable and resilient drainage systems including composting toilets and anaerobic digesters. For electricity, photovoltaic panels paired with batteries could provide another source of electricity for the schools.
These principles and recommendations were handed over to local contractors for development. Our designs are affordable, easily replicable, and adaptable to suit local specific site conditions. We’re optimistic that this work will create a ripple effect through the continued implementation of PEAS in Africa.