In this article I will write how to cool down cities with cool infrastructure solutions.
This means architectural, technological advancements which needed to create cooler cities which highly needed in the new summer heat waves. Architects, developers and citizens of urban places work together to create cooler urban infrastructures since we all feel how years get hotter & hotter.
Furthermore governmental policies and city planning has a role in this as needs to create codes & regulations, which help initiatives and make them accessible for everyone.
Urban Heat Mitigation
Why cooling down is important?
In the recent heatwaves what most of the urban residents experienced in the world we might do not need to clarify why cooling down cities is important at all. We need to write more how to cool down cities at all? Since more and more people live in cities and the demand and importance will only increase.
To begin with cooling down cities involves implementing strategies to combat the urban heat island effect around and inside cities.
Urban heat island (UHI) effect
A phenomenon where urban areas experience higher temperatures than their surrounding rural areas. This temperature difference is primarily caused by human activities and the built environment in cities. As cities grow and develop, they tend to replace natural landscapes with impervious surfaces, e.g.:
- concrete and
- asphalt, and
- structures that absorb and retain heat, leading to several factors that contribute to the UHI effect.
With the help of urban planning policy and code makers can incorporate green spaces and cooling strategies into city planning and development projects to prioritize environmental sustainability.
Urban policies and regulations with business support and solutions can be a good answer the how to cool down cities? question.
Sustainable Urban Cooling Solution
A range of innovative strategies and technologies aimed at mitigating the growing urban heat island effect and creating more liveable and eco-friendly cities
- Green Roofs,
- Water Features,
- Permeable Surfaces,
- Smart Urban Planning,
- Cool Walls and Facades,
- Urban Forests and Parks,
- Cool Community Spaces: shaded public spaces with canopies, pergolas, or shaded structures
- Energy-Efficient Building Design: passive cooling techniques and natural ventilation
- Solar-Powered Air Conditioning: utilizing solar energy to power air conditioning systems reduces carbon emissions and lessens the urban heat island effect.
City Cooling Strategies
One of the most effective answer is ‘cool infrastructures’ for the ‘how to cool down cities?’ question.
Cool Roofs, Pavements, Coating
Use reflective materials to
- reduce heat absorption from sunlight,
- keeping the building interior cooler and
- reducing the demand for air conditioning.
Several countries initiated cool roof programs that promote the installation of light-colored or reflective roofs on buildings to reduce energy consumption and lower urban heat island effects.
Programs can be found in Australia, India, the Philippines, among others.
Using reflective and permeable materials for pavements and roads to minimize heat absorption and reduce the urban heat island effect.
Cool Pavements Coating
Apply cool pavement coatings to existing roads and parking lots to increase reflectivity and reduce heat absorption.
- porous asphalt or
- open graded friction course asphalt pavements (improve roadfriction in wet weather), and
- rubberized asphalt (reduce noise too), pervious concrete, brick or concrete pavement blocks.
Solar reflective “cool” pavements stay cooler in the sun than traditional pavements.
Los Angeles’ Cool Pavement Program
For instance Los Angeles experimenting with cool pavement coatings on roads and parking lots to
- reduce heat absorption and
- mitigate the urban heat island effect.
Craig Shaw, the overseer of the Cool Streets initiative, which is a component of Los Angeles’ Green New Deal launched back in 2019, mentioned that the concept of cool pavement was initially introduced in the city in 2015, specifically at Balboa Park. Once the reflective coating is applied to the pavements, the temperature of individual streets can be reduced by an impressive 10-12 degrees Fahrenheit.
Install shade structures in public spaces, walkways, and transit stops to
- protect pedestrians from direct sunlight and
- provide cooler resting areas.
Next to the above mentioned solutions use heat-resistant construction materials for buildings and infrastructure to
- reduce heat absorption and
- minimize the heat island effect.
- public transportation,
- cycling infrastructure, and
- pedestrian pathways
to reduce the reliance on private vehicles and lower emissions contributing to heat.
Thermal Mass Cooling
In addition to the previous examples buildings with high thermal mass, e.g.: concrete or stone, can store coolness during the night and release it during the day, reducing the need for active cooling.
District Cooling Systems
Centralize cooling production and distribute chilled water to multiple buildings, reducing the energy required for individual cooling systems.
Utilizing solar energy to power absorption chillers or other cooling systems. Significantly reduce reliance on the grid and lower operational costs.
Energy Recovery Ventilation (ERV) Systems
ERV systems recover waste heat from exhaust air and use it to pre-cool incoming fresh air, reducing the load on the cooling system.
Building Automation and Controls
Smart building management systems and advanced controls optimize cooling operation by adjusting settings based on occupancy, weather conditions, and other factors.
Incorporating natural ventilation strategies, e.g.: operable windows and passive cooling techniques, which reduce the need for mechanical cooling during milder weather conditions.
How to cool down cities as an individual? Citizens and residents play crucial role in helping to cool down cities and combat the urban heat island effect.
Use Sustainable Transportation
Opt for public transportation, cycling, or walking instead of using private vehicles to reduce heat and air pollution from fossil fuel emissions.
- Public Transit
- Cycling Infrastructure
- Carpooling and Ride-Sharing
- Integrated Transport Systems
- Transportation Demand Management (TDM)
- Urban Planning for Transit-Oriented Development
Practice Water Management
Capture rainwater and use it for irrigation to reduce pressure on water resources and support green spaces.
Practice water conservation at home by using water-efficient appliances and reducing outdoor water usage to preserve water for cooling green infrastructure.
Telecommuting and Remote Work
Telecommuting and remote work can help reduce heat waves in cities with
- Reduced Commuting
- Lower Energy Consumption
- Less Urban Activity
- Conservation of Green Spaces
- Fostering Sustainable Habits
- Flexibility for Heat-Adaptation
White Surfaces for Heat Reduction
If possible, opt for light-colored or reflective surfaces on pavements, driveways, and roofs to reduce heat absorption.
If you ever wondered why in the Mediterranian coast in Santorini’s Oia village every buildings is white, now you have the idea. Light-colored and reflective surfaces can help in reducing heat absorption.
Light-colored surfaces, known as cool or reflective surfaces, reduce heat absorption compared to dark-colored surfaces.
This phenomenon is mainly due to the difference in their solar reflectance (albedo) and thermal emissivity.
Higher Solar Reflectance (Albedo)
Light-colored surfaces reflect a higher percentage of sunlight back into the atmosphere, preventing it from being absorbed by the surface.
This is measured on a scale from 0 to 1, with 0 indicating total absorption and 1 indicating total reflection.
White surface vs. darker-colored surfaces
The albedo of a white surface can be close to or even equal to 1, meaning it reflects nearly all of the incoming solar radiation. In contrast, darker-colored surfaces, e.g.: asphalt or a black roof, have lower albedo values. These surfaces have an albedo ranging from around 0.05 to 0.20, which means they absorb a significant portion (up to 95% or more) of the incoming solar radiation.
Another example the city in Montecorto in Spain.
Increasing solar reflectance (albedo)
Studies shown that increasing the albedo of urban surfaces through cool roofs, cool pavements, and light-colored coatings have several benefits:
- Surface Temperature Reduction: cool roofs and pavements reduce surface temperatures by 30-50°F (17-28°C) compared to conventional dark surfaces.
- Cooling Effect on Surrounding Areas: by reducing the heat absorbed by buildings and streets, cool surfaces help lower air temperatures in the surrounding area, creating a cooling effect.
- Energy Savings: cool roofs significantly reduce the cooling energy demand in buildings, leading to lower electricity consumption and greenhouse gas emissions.
- Improved Air Quality: lower temperatures lead to a reduction in the formation of ground-level ozone, which is a harmful air pollutant.
Another example for this reflectance the Sheikh Zayed Grand Mosque in Abu Dhabi.
As next to cultural and architectural considerations like traditional islamic architecture, where white symbolizes purity and simplicity, it is believed to reflect the light and heat of the sun, helping to keep the interior of the mosque cooler in the hot desert climate.
Lower Thermal Emissivity
Light-colored surfaces tend to have lower thermal emissivity, which means they radiate less heat back into the surroundings at night, leading to cooler nighttime temperatures.
According to the Lawrence Berkeley National Laboratory, light-colored surfaces reflect up to 80-90% of incoming solar radiation, while dark surfaces typically reflect only 10-20% of solar radiation.
This means dark surfaces absorb a significantly larger amount of solar energy, leading to higher surface temperatures and contributing to the urban heat island effect.
White Roof Initiatives
Various cities around the world implemented “white roof” initiatives where buildings are encouraged to use light-colored or white roofing materials to reflect sunlight and reduce heat absorption. Examples of cities include New York City in the United States and Athens in Greece.
Solar Reflective Pavements
Some cities, like Los Angeles in California, experimented with the use of solar reflective coatings on pavements and roads. These coatings are designed to reflect sunlight and reduce surface temperatures, contributing to a cooler urban environment. Read more about it here.
In certain pilot projects, solar roadways developed, featuring light-colored, solar panel-covered surfaces. That generate renewable energy while reflecting sunlight and reducing heat absorption.
Light-Colored Plazas and Public Spaces
Many public plazas and open spaces in urban areas are designed with light-colored pavements or materials to reflect sunlight and create more comfortable gathering spaces for residents and visitors.
Desert City Planning
In desert regions, urban planners often use light-colored materials and reflective surfaces for buildings, roads, and pavements to counteract the extreme heat and create more habitable living conditions. Examples can be found in cities like Dubai, United Arab Emirates, and Las Vegas, Nevada, USA.
In large-scale solar farms, solar panels are often installed on light-colored mounting structures that reflect sunlight onto the solar cells, increasing their efficiency and energy generation.
These all practical strategies help citizens in and outside of the cities too to answer properly for the how to cool down cities question.
In the next article I will write more how to make cities not just cooler, but greener too.
Thank you for reading.