This article is available also in spanish here

Could an ultra-white paint cool the cities of the future?

My list

Author | M. Martínez Euklidiadas

Could cities combat urban heat if they were painted white? Theoretically they could, and historically they have. Recently, Xiulin Ruan, a Purdue University professor of mechanical engineering, created the whitest paint on record, capable of reflecting 98.1% of sunlight.

Albedo, warm cities' greatest ally

The narrow and white streets of the villages in Andalusia (Spain, above Malaga) are known worldwide. Oia, a village on the archipelago of Santorini, renowned for dazzling ships and also Ashgabat, the capital of Turkmenistan, famous for having the world's highest density of buildings made from white marble, use similar mechanisms.

Hundreds of towns across the world have learnt to adapt over thousands of years, cladding buildings with marble, painting houses with whitewash, made of slaked lime or using minerals. By increasing the white area, they also increased the albedo, the solar radiation reflected by a surface. Dark surfaces absorb solar radiance, light surfaces reflect it.

The whitest paint in the world to cool buildings

The pigment developed by Xiulin Ruan and his team is capable of reflecting 98.1% of solar radiation. At the other end of the spectrum, the Vantablack pigment (the blackest shade of black) absorbs 99.96% of light.

In practice, painting buildings with the whitest shade of white -formally nanoparticles of barium sulfate- entails temperatures of around 4.5 ºC below exterior temperatures, and therefore lower use of temperature control systems, which require energy.

Can paint cool our cities?

These solar geoengineering proposals to cool large urban areas, may provide some relief to combat the heat island effect experienced in many cities, particularly if they are combined with large green areas, vegetation providing shade or sources of water.

It is not a cure, and sometimes it can even lead to conflicts ---a completely white property will reflect, through the albedo effect, on to the building in front---, but with the help of other public policies, undoubtedly we would create more human cities.

ultrawhite paint 2

For example, a completely white building next to a black asphalt surface, without any elements to provide shade, is not smart. The asphalt will reflect on the building all day long and, regardless of how white the building is, it will get hot. Furthermore, the area will be unusable for pedestrians.

All that reflects is not snow...

In addition, white pigment technology is not particularly easy to apply compared with other white coloring. Although the idea is to use this pigment to cover entire cities and prevent them from getting warm, it is important to point out that the alternative use of conventional paint is much more convenient.

There are also other alternatives to reduce our dependence on air conditioning, other than color. Green roofs are a great example of heat dissipation which also cools the environment and the streets. Another example are roofs with water, although both options entail certain technical complications, such as damp issues.

Painting buildings white is another option

ultrawhite paint 3Daily Sea Surface Temperature

While writing this article, the city mentioned at the beginning of the same is experiencing an unprecedented heatwave, (the last of its kind dates back to 1942) and the Mediterranean has reached its highest ever recorded temperature (map).

In their adaptation to the climate crisis and in order to build more human cities, towns around the world are coming together to combat soaring temperatures.

Image | Tabea Schimpf

Related content

Recommended profiles for you

Remember to activate your profile to network!
Activate profile
SG
Sayan Ganguly
Invest India (Department for Promotion of Industry and Internal Trade)
Associate - Technology Development Fund (DRDO) Desk
SS
Setiawan Setiasan
Bppw Lampunhg
Architect
NM
Nasser Mohammed Mohammed
Verax enterprises pvt ltd
CEO
Ulari Teder
Ulari Teder
EyeVi Technologies Ltd
Sales Director
Victor Sada
Victor Sada
Arcus Infrastructure Partners LLP
Investment Executive
ER
Esteban Rodriguez
Universidad de los Andes
Ted Mengers Mengers
Ted Mengers Mengers
Pyranak Design Group
CEO
salman saedan
salman saedan
salman a bin saedan real estate Group
CEO
Carlos Horacio Torres Matallana
Carlos Horacio Torres Matallana
UPV/EHU
Msc student
MZ
MargareTA Zidar
Energy instutute Hrvoje Pozar
Deputy Head of Energy Efficinecy Department
vr
vadendra rao
iPortal Automation
CEO & TECH Head
RR
Rodrigo RodrigoJUU
SOAInt
Presales Engineer
MR
Matthew Rios
Axis Communications
RSM/AXIS
Chirag Mistry
Chirag Mistry
Furniture Arts
Business Development
MD
Mauricio Dobles
Pacific Tree Co.
General Director
OS
Oscar Saco
DOMINION
Head of Automation Department
NP
Nicolas Petitfils
ARaymond
Industrial Markets - Marketing
Alenka Lucesole Sinkec
Alenka Lucesole Sinkec
Student
National University of La Plata
Eitan Grosbard
Eitan Grosbard
Tactile Mobility
Business Development VP
Dnyaneshwar Dole
Dnyaneshwar Dole
Jayawal neco industries Ltd Nagpur Plumbing Constructio Infrastructure industries
Marketing n Customer service

SmartCity
Thank you for registering to Tomorrow.City. You can now start exploring all the content for free!
Only accessible for registered users
This content is available only for registered users
TO: $$toName$$
SUBJECT: Message from $$fromName$$