Super cool building materials prove powerful arsenal against climate change
School of Built Environment
New building materials that reflect rather than absorb solar energy can reduce peak temperatures in our cities by up to four degrees.聽
New building materials that reduce urban temperatures, and counteract the effects of climate change, will be produced in a research partnership between UNSW Sydney and the University of Sydney.
The so-called super cool roofs, pavements and coatings for buildings reflect rather than absorb solar energy. They can reduce peak temperatures in our cities by up to four degrees, enough to save lives, says Scientia Professor Mattheos (Mat) Santamouris.
鈥淥ne of the major problems in the built environment is urban overheating, or regional climatic change,鈥 the Anita Lawrence Professor of High-Performance Architecture says. 鈥淎s our cities heat up, heat-related morbidity and mortality rise.鈥
In 2020, 593 and 391 people died from heat-related deaths in Melbourne and Sydney respectively, a substantial increase from 289 and 176 in 2007, according to the Australia State of Environment.聽
Countering the urban heat island effect
Overpopulation and rapid urbanisation are transforming our cities into urban heat islands, Prof. Santamouris says. Human activity 鈥 waste heat from industry, cars and air conditioners 鈥 drives up city temperatures making them significantly warmer than surrounding areas. This affects more than 500 cities worldwide.
鈥淭he way we build [also] increases the temperature of our cities. We鈥檙e using [heat-absorbing materials like] asphalt, we鈥檙e using concrete,鈥 Prof. Santamouris says.
Super cool roofs and pavements by contrast reduce the energy needed for cooling. This in turn decreases carbon-dioxide emissions that increases the magnitude of climate change. This makes our cities more economical, environmentally friendly and liveable, he says.
The new-generation materials were tested as part of a study to reduce temperatures in Australian cities, and mainly in the frame of an ARC Discovery Project.
The study found that introducing super cool materials with other heat-mitigating strategies, such as increased greenery and shade, could save around 10 lives per year, per 100,000 residents.
鈥淯nder the sun, [with] 42 degrees ambient temperature, the [super cool] materials鈥 surface temperature was 25. It's a natural air condition without expending any energy 鈥 super cool materials,鈥 the energy physicist says.
鈥淎nd all these new technologies and new materials have been developed here in Australia.鈥
Application of cool material in cities can result in a reduction of peak ambient temperature. Image: Supplied.
Promoting energy economy with government
Prof. Santamouris and his team are partnering with the Department of Industry, Science, Enterprise and Research (DISER) on two projects to promote energy efficiency in the built environment.
The team will provide cost-benefit analyses and scientific documentation on the adoption of cool roofs in Australia, and ways to improve energy efficiency in existing commercial buildings, such as office buildings, aged-care facilities, hotels, childcare and shopping centres.
With around 40% of the total energy consumption in developed nations attributable to buildings, there is huge potential for impact, Prof. Santamouris says.
鈥淭he reduction of energy use and associated greenhouse gas emissions through energy conservation measures is vital to achieving energy and climate goals in the cities,鈥 he says.
Cool materials were applied in the mitigation case and a reduction of the ambient temperature was observed. Extracted from the project report for Cooling Riyadh. Image: Supplied.
Princely project a win for Australian tech and knowledge exchange
Prof. Santamouris is applying his research to reduce temperatures in Riyadh in Saudi Arabia, one of the world鈥檚 hottest cities. The Royal Commission of Riyadh has engaged his team to develop an all-pervasive heat-mitigation plan, the largest of its kind.
The project recognises Australia鈥檚 world-leading research and technology in the field, and delivers significant health, sustainability and economic outcomes. They use computational tools empowered with rich urban datasets to model building performance at the urban scale, identify energy retrofits and inform urban planning.
Extensive aerial monitoring using airplanes and infrared technologies, performed by industry partner National Drones, will map the city鈥檚 thermal conditions. While large-scale high-resolution simulations of the city will evaluate different scenarios to decipher optimal strategies.
The project also considers the city鈥檚 vegetation, water, ventilation and introducing super cool materials. The team is coordinating similar studies for the cities of Dubai, UAE; Kolkata, India; and Kuala Lumpur, Malaysia in collaboration with local researchers.
A more equitable energy blueprint
Energy conservation also has a flow-on effect to equity, Prof. Santamouris says. Today 20% of the population in developed countries cannot afford to cover their energy needs due to low income and low-quality housing, he says.
鈥淭he temperature difference between Eastern and Western Sydney during summer, for example, is up to 10 degrees. In a distance of 60 kilometres, that's tremendous,鈥 he says.聽
鈥淭his has a tremendous impact on the quality of life of people in Western Sydney. They spend almost 100% more energy on cooling. They have much higher mortality rates.鈥
The less energy we need, the greater the thermal satisfaction of all people, he says. And that is the end goal for him. The most powerful research pivots on pragmatic altruism, he says.
鈥淩esearch must advance knowledge, help solve existing problems, and cover existing knowledge gaps to better the quality of life,鈥 he says. 鈥淚t must advance the global good for the improvement of society, to protect the lives of citizens.鈥澛
Prof. Santamouris is ranked the top most cited scientist for building and construction globally for 2019 and 2020 in the Meta-Research Innovation Center at Stanford.聽He and his team are involved with more than 200 large-scale heat-mitigation projects around the world in Europe, the Americas, Asia, and Australia.聽
Lead image:聽Super cool roofs and pavements by contrast reduce the energy needed for cooling in cities. Image: Shutterstock.
This article was originally published in 2022.