We must reduce greenhouse gas emissions. This is the number one priority and can reduce the number of extreme hot days in the long run.
Editor’s note: 30 degrees, still acceptable, 35 degrees, unbearable, 38 degrees, the gods are uncomfortable! How does the city resist the hot weather? Let’s take a look at the strange tricks that the world’s major cities have come up with! This article was compiled from the article titled “Cities are getting hotter, but we can redesign them to keep us cool”.
The hot weather seems to be more and more common. In order to make the people feel more comfortable, many cities are actively looking for solutions to deal with the hot weather.
For example, if you are riding a bicycle in the Echo Park neighborhood of Los Angeles, you will see the street surface suddenly changing color and the black asphalt turning white. More than a year ago, Los Angeles was coated on the road with a special coating that was lighter in color and reflected sunlight; Los Angeles hoped that the white coating would cool the city.
Like most cities, Los Angeles is also plagued by the heat. A survey report plots temperatures across the United States and finds that if greenhouse gases continue to increase at current rates, the number of hot days in the United States (more than 37.7) will be at least double that of the Middle Ages.
Some cities are even worse, like Miami, and by the end of the century, the number of hot days will reach 153 days. The weather was not so hot before, and now it is getting hot. The old buildings are not ready for the hot days, and the city has to work hard to remedy it. In June, Berlin’s average maximum temperature was only 22.2 degrees, but one day last month it climbed to 38.3 degrees Celsius. Cities are also affected by the “urban heat island effect”: sidewalks and buildings absorb and release large amounts of solar radiation, causing temperatures to rise further.
What should I do? There are several ways to cool the city, such as adjusting the infrastructure, using solar cells and batteries to form a microgrid. If hot weather causes the grid to smash, they can supply air conditioning. The city can also introduce cooling technology, such as mining geothermal energy. Among the many options, there are several methods that are both simple and practical.
Matt Petersen, CEO and President of Los Angeles Cleantech Incubator, said: “We must reduce greenhouse gas emissions. This is the number one priority and can reduce the number of extreme hot days in the long run. But now the extreme hot days have emerged, we must Take appropriate measures to cool the streetsCool down the roof and plant trees to reduce the number of hot days.
Use trees to cover cities and buildings
Melbourne is drawing a “tree cover map” for city streets, which is actively planting trees. Melbourne is preparing to double the number of trees by 2040. Milan is preparing to plant 3 million trees. There are many benefits to planting trees: trees cover the streets, and water evaporates from the leaves, which can cool neighboring neighborhoods.
Dallas, USA is advancing a new project that maps areas of the city that are overheated by the lack of trees and then begins planting trees in key areas where pedestrians move. In 2016, Madrid developed a plan to plant trees in places where trees can be planted. Sometimes the trees are simply planted on the roof and on the facade.
The balcony of the Bosco Verticale building in Milan is full of trees. Brian Swett, director of engineering and sustainable real estate at engineering firm Arup, said: “We design such a balcony mainly to make the building truly accommodate the green infrastructure.”
Coating the streets and roofs
In New York City, more than one million square feet of roof have been coated with a white reflective coating over the past 10 years. The coating can reduce the internal temperature of the building, make the people more comfortable and reduce the air conditioning time; just like the car, the air conditioner is also a source of heat and make the city hotter. The green roof also cools the building and cools the nearby neighborhood. Swett said: “From a city perspective, if you only build a roof garden on a building, it will not help, only a large-scale implementation can have a huge impact.”
Tokyo also took action and laid a cool sidewalk on the street. Some cities build new sidewalks that can grow grass and grow freely.
Los Angeles’s three-pronged approach: building cool roofs, planting trees, and building cool sidewalks. Petersen said: “We see a difference of 20 degrees Fahrenheit (6.6 degrees Celsius) between construction and non-construction, which means that the conventional black sidewalk is 6.6 degrees higher than the paved road with cooling coating.” Petersen also said that Los Angeles encourages manufacturers to develop New street coating. Petersen’s organization is currently testing a variety of new coating materials.
Designing a cool building
If you want to cool the interior of the building, you can design a green cool roof and exterior wall. In addition, there are other ways to reduce air conditioning usage. When the sun shines directly on the window, it can be blocked by an automatic window. The automatic window will open at night, at which point the sensor will automatically detect that the temperature has dropped and the window is closed when the temperature rises.
Want to cool the building, material selection is also critical. Because of the thermal mass effect of concrete, the building can be cooled in advance of the heat wave. Swett said: “If everyone is at the same timeTurning on the air conditioner will put pressure on the power grid and cause power failure.
Extreme weather can be predicted in advance, so before the heat wave arrives, you can cool the thermal mass building and keep the building cool so that it won’t drag the grid. When designing the building, Arup uses special tools to predict the relationship between the building and the future climate.
Think about the shape of the city itself
In addition to changing the built environment, cities can also think about how citizens live. Cars not only emit greenhouse gases, they also emit heat and make the city hotter.
Because there are too many cars, more streets and more parking lots are needed, which will increase the local temperature. Stephen Coulston, director of architectural design firm Perkins and Will, said: “After the Second World War, we began to introduce new zoning strategies to separate areas by purpose, such as isolating large single-family homes, placing them in one area, or industrializing The retail area is separated.”
“In the past, some people’s activities may not need a car, and the new layout inhibited such activities. In some cases, some places may be connected together, you can live in Area A, then walk to the market, walk to retail Center, there is no need to take the car, now it will not work.”
The city encourages people to drive less, redesign bicycle lanes and sidewalks, provide new mixed-use vehicles, and is close to the public, and these strategies can help cool the city.
Translator: Xiaobing Hand