A recent study conducted by UNSW Sydney reveals that it is possible to significantly reduce temperatures in one of the hottest cities in the world while also lowering energy costs. The findings, published in Nature Cities, demonstrate a multi-faceted approach to cooling Riyadh, the capital city of Saudi Arabia, by up to 4.5°C. This strategy combines the use of highly reflective building materials, irrigated greenery, and energy retrofitting measures.
The study, in collaboration with the Royal Commission of Riyadh, is the first to explore the large-scale energy benefits of modern heat mitigation technologies when implemented in a city. The results highlight the substantial impact that these advanced techniques can have on reducing urban overheating, decreasing cooling needs, and ultimately improving quality of life.
Riyadh, located in the center of a desert, is known for its scorching temperatures, which can exceed 50°C during the summer. Climate change and rapid urbanization only exacerbate the city’s overheating issues. The lack of green spaces and the prevalence of artificial surfaces made of materials like asphalt and concrete contribute to the heat trap. Furthermore, car pollution and industrial activities add additional heat, further raising the city’s temperature.
To investigate potential solutions, the research team from UNSW ran large-scale simulations of Riyadh’s Al Masiaf precinct. The simulations evaluated different heat mitigation scenarios and their impact on the city’s temperature and cooling requirements. The modeling considered various combinations of super cool materials, vegetation types, and energy retrofitting levels.
The results showed that implementing a combination of super cool materials on building roofs and increasing the number of irrigated trees could decrease the outdoor temperature in Riyadh by nearly 4.5°C during the summer. This strategy would also lead to a 16% improvement in cooling energy conservation.
However, the researchers cautioned against blind implementation of cooling techniques without proper scientific optimization. For example, the use of non-irrigated greenery could backfire and actually increase the city’s temperature. The right combination of advanced heat mitigation technologies and techniques is essential for effective cooling.
Lowering the city’s temperature has numerous benefits, according to UNSW Scientia Professor Mattheos Santamouris. It increases thermal comfort for residents, reduces health issues related to extreme heat, decreases pollutant concentrations, and improves human productivity. Similar cooling strategies implemented in other cities have also been found to reduce heat-related deaths.
The study also investigated the energy impact of retrofitting measures for all 3,323 buildings in Riyadh. The combination of optimal cooling technologies with energy retrofitting options, such as improved windows, insulation, solar panels, and cool roofs, could reduce cooling demand by up to 35%.
This significant reduction in energy needs would lower costs associated with cooling while enhancing the overall quality of life for the local population. The researchers intend to collaborate with the Royal Commission of Riyadh to implement the tailored heat mitigation plan, which would be the largest of its kind in the world.
Once implemented at the city scale, these advanced heat mitigation technologies are expected to deliver long-lasting health, sustainability, and economic benefits for Riyadh. The study paves the way for future cities facing similar challenges to adopt innovative strategies that promote cooler and more sustainable urban environments.
