Light-reflecting coatings on building roofs and irrigated green spaces reduce the temperature in Riyadh by 4.5 degrees (Shutterstock)
In a new scientific study, an international team of researchers has revealed a pioneering strategy that could reduce scorching temperatures in major cities located in a hot desert climate while reducing energy costs.
The results of the study conducted in the city of Riyadh showed that temperatures there could be reduced by up to 4.5 degrees by combining a new type of light-reflecting coatings with irrigated green spaces.
This study - published in the journal Nature Cities - is the first of its kind to examine the benefits of applying innovative heat-reducing technologies in hot cities, and offers a promising solution to the ongoing challenge facing many urban areas around the world as temperatures continue to rise. Due to global warming, researchers from the Australian University of New South Wales participated in its completion in cooperation with the Royal Commission in Riyadh and the University of Athens.
Heat island phenomenon within cities
With the increase in the population of urban areas in the world, the areas of cities increased, and buildings, asphalt roads and roofs expanded at the expense of soil and green natural spaces. This expansion, along with the conditions of global warming we are experiencing today, has produced so-called heat islands within cities, which are characterized by relatively high temperatures compared to the surrounding areas.
A drawing of the heat island phenomenon over major cities (University of Michigan)
Some studies have shown, according to a report published on Earth.org, that the heat island effect can lead to an increase in urban area temperatures of up to 7 degrees Celsius during the day and 12 degrees Celsius at night compared to rural areas. Rising temperatures can lead to a deterioration in air quality, and an increase in the concentration of ground-level ozone and other pollutants.
It is estimated that extreme urban heat affects more than 450 cities around the world, increasing energy consumption needs, negatively impacting health, and raising rates of heat-related morbidity and mortality.
In the Saudi capital, Riyadh, maximum temperatures exceed 50 degrees Celsius during the summer, making it one of the hottest cities in the world. The combination of rapid urbanization and climate change is raising temperatures, with resulting increases in energy consumption and adverse health effects.
Supercooling materials and irrigated trees to reduce heat
In the new study, the researchers conducted large-scale simulations to reduce heat in the Al-Masif region in Riyadh, which included evaluating the energy performance of 3,323 urban buildings. The simulation included experimenting with 8 different cooling scenarios with the aim of determining the optimal strategies to reduce temperatures in the city and reduce energy needs.
Al-Masif area in Riyadh, where researchers evaluated the energy performance of 3,323 buildings (Nature)
According to a statement published on the University of New South Wales website, the modeling - which took into account the use of heat-modulating materials developed by researchers and types of plants - found that it is possible to reduce external temperatures in the city by about 4.5 degrees Celsius during the summer, and it is also possible to increase energy efficiency. Used for cooling up to 16%.
The recommended cooling scenario to reduce temperatures in the city of Riyadh includes: Increasing the number of irrigated trees to more than double their number today to improve cooling resulting from the evaporation of water from these plants (transpiration).
It also includes the use of ultra-cooling materials that you apply to the roofs of buildings. These materials are a type of radiant coatings that have appeared in the past few years and contain materials such as chromium and fluorine and reflect light.
A previous study conducted in the Indian city of Kolkata showed that these materials can maintain a temperature of only 25 degrees when the ambient temperature reaches 42 degrees Celsius, and they can provide free cooling or even heating of buildings when used as passive components integrated into the building envelope, or devices. Active to provide pre-cooling and free ventilation.
The study's authors warned that ill-considered implementation of urban cooling techniques that are not based on a scientific basis, such as the use of non-irrigated green spaces, may lead to a significant increase in city temperatures.
Doubling the areas of irrigated trees contributes to reducing heat and improving the quality of life in hot cities (Shutterstock)
Improving the quality of life and reducing the concentration of pollutants
Professor of Science at the University of New South Wales and the supervisor of the study, Professor Santamores, confirmed in a statement mentioned in the statement that implementing the correct combination of the proposed cooling technologies can reduce the ambient temperature, which improves the quality of life for the population and reduces health problems resulting from extreme heat. This combination also allows to reduce the concentration of pollutants and improve human productivity. Previous research has found that implementing similar cooling strategies in other cities could help reduce heat-related deaths.
In addition, the process of simulating the impact of the proposed cooling scenario on energy use in all buildings included in the study showed that improving insulation in windows and ceilings could reduce the demand for energy consumption allocated to cooling by up to 35%, and this will contribute to a significant reduction in energy needs. In reducing the costs associated with cooling in Riyadh while improving the quality of life for its residents, Santamores says.
In the near future, the research team aims to cooperate with the Royal Commission in Riyadh to implement the designed heat reduction plan, which is considered the largest of its kind in the world.
Source: Al Jazeera + websites