Improving Outdoor Thermal Comfort by Creating Public Spaces in Vehicular Dominated Streets in Bulawayo

The Central business district of Bulawayo is made up of 17 avenues and 11 streets which are wide (approximately 27-32 metres), in a grid pattern on a flat terrain. The wide streets are attracting more vehicles including a concentration of vendors lining up on the streets selling their wares. This has resulted in a city centre without usable public and pedestrian space which people can use safely. This research aimed at developing a concept of reclaiming space from vehicular traffic in the streets and use it for attractive public spaces incorporating different social public activities with outdoor thermal comfort being a requirement. The identified needs of the people include; eating spaces, relaxation spaces, street vending spaces and public speaking and street theatre spaces. Space is created from the streets to accommodate the different needs of the people by zoning the city centre into islands. The islands organize the city roads into two different networks; the primary network for high traffic volume of public transport at higher speeds and the secondary network for low traffic volumes of private and emergency vehicles at low speed.
Strategies for achieving thermal comfort in the street spaces between 0700 hrs till 1800 hrs are investigated by first conducting a climate analysis of Bulawayo. The Universal Thermal Climate Index (UTCI) outdoor comfort analysis results show that in the coldest season (June to August) there is a 70% comfortable (no thermal stress) perception and the hottest season (September to November) there is a 40% comfortable (no thermal stress) perception. The main reason for this is because out of the annual total horizontal insolation of 1856kWh/m2 which Bulawayo receives, 547kWh/m2/ (29% of the total) is received in the hottest season. This informs the target period of concern for thermal comfort to be the hottest period during the time (0700hrs till 1800hrs)
A thermal behaviour analysis using the software TRNLIZARD proves that outdoor thermal comfort can be achieved during the hottest period to above 70% comfortable (no thermal stress) using the strategies of; shading direct solar radiation, increasing air movement by fans, adiabatic cooling, cooling by plants through evapotranspiration and the use of cool and green surfaces.
The research therefore offers a solution that can reshape the city centre of Bulawayo by providing highly comfortable public spaces in the streets. This ultimately provides an inclusive design that facilitates social inclusion and empowers the local people through enhancement of socio-economic activities.

Project mentors: Jochen Lam, Tommaso Bitossi

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Innocent Mhandu – Zimbabwe

Innocent Mhandu – Zimbabwe

Innocent is a Zimbabwean architect with a Master of Architecture degree from the National University of Science and Technology, Bulawayo (NUST) Zimbabwe. He has worked with different architectural companies in Harare, and has also been teaching and researching in the Department of Architecture at The National University of Science and Technology, Bulawayo in Zimbabwe.