For a brief moment in the middle of last month, London was hotter than Cairo. Temperatures reached 40C, the hottest this country has ever seen. Ice creams melted. Train tracks expanded. The nation wilted.
These temperatures would have come as no great shock to the experts. Heatwaves like July’s will become increasingly common, and it will be cities that suffer the most; because of the “urban heat island” effect, they are often up to 10 degrees hotter than rural areas.
So, if London is going to continue to experience temperatures hot enough to cook bacon on the pavements and turn tarmac into black, bubbling rivers, are we going to fry too? Luckily there are great minds working to mitigate some of the issues. Welcome to the London of the future...
Going underground?
Think of air conditioning as your problematic uncle: you love it but in the long run it’s actually doing more harm than good. By 2050, more than a third of the world’s electricity could be used to cool the world. Bad. In heatwaves, electric grids come under enormous strain as everyone turns on their fans and air conditioning. Even worse, air conditioning units constantly spew out hot air into the outdoors, raising the temperature. This is the vicious air conditioning cycle: whenever you cool yourself down with it, you’re making the rest of the world hotter.
One increasingly popular technique to help cool indoor spaces takes place beneath the ground. Ground source heat pumps are a renewable energy system that use the heat stored in the ground to either heat or cool indoor spaces. “In the summer,” says David Broom, managing director of Kensa Contracting, who build heat pumps, “the ground is colder than the air temperature, so what we’re able to do is take that cold water from the ground loop and run it through a fan coil within the building and basically distribute free cooling into the room.”
In a test home in Cardiff, Kensa kept the indoor temperature at 20.5 degrees for eight hours while it was 32 degrees outside.
In Cardiff, Kensa kept the indoor temperature at 20.5 degrees for eight hours while it was 32 degrees outside
Air conditioning is also a very wasteful method of cooling; the more air conditioning units have to lower the temperature, the more waste heat they create. Ground source heat pumps don’t waste heat like this, they put it into the ground and store it for later use. It is a technology that represents a natural transition away from carbon emissions – something that will be crucial in the fight to lower temperatures. From 2025, gas boilers in new homes will be phased out, and by 2098 the government aims to be installing 600,000 ground source heat pumps a year.
Catch the sun
In order to fight the effects of the sun, we can harness it, and around the world there are all kinds of new development in solar power to provide inspiration. In Israel, Nostromo Energy have a ground-breaking solution as to what to do when the sun sets: their eco-friendly technology can sit on rooftops and create ice capsules during off-peak hours, sustainably storing energy and sending it to the building’s cooling systems to be used during the hours in which the sun is beating down.
Meanwhile in Los Angeles, Professor Aaswath Raman has engineered a type of film, made from glass and hafnium dioxide, which cools down when the sun is shining on it. His and his colleague’s company SkyCool recently used panels coated in the film to pump water into a supermarket’s air conditioners, minimising the amount of electricity they used by around 20 per cent.
Back in the UK Naked Energy has the patent on a unique form of solar collector that can generate renewable electricity for chillers far more efficiently than regular solar PV panels. Their product is on the Active Office outside Swansea, which is the first building in the UK to produce more energy than it consumes. “Why aren’t all the buildings in London like that?” Naked Energy CEO Christophe Williams asked the Standard. Good question, Christophe.
Turn over a new leaf
The roofs of the future may not just be solar, they may be bio-solar. Sitting side by side with products like Naked Energy’s panels would be plants and trees, shading the roofs, helping to cool down the air temperature, and even – absolute legends – mitigating against flooding by trapping more rainwater. They’re even proven to boost people’s mood.
So, in the war against the heating of the city, trees are a big weapon in our arsenal. In other countries – Singapore, most notably – the delicious idea of a ‘garden city’ is exactly what London could aspire to. As Alan Fogarty, a sustainability partner for engineering consultancy Cundall, says, trees could fill the gap that the city’s cars leave: as more vehicles become automated and electric, we may start to drive around using shared cars docked at electric charging points. The driveways in front of houses could have their gardens reinstated. Trees could begin to own this city again. Especially if we use another Israeli invention to prevent them destroying the pavements: the fantastic TreeTube. Assembled like Lego bricks below the asphalt, these units let the roots of our city’s trees grow in a steel and plastic tunnel.
Greening cities is good but more radical and more effective is ‘blueing’ cities
Trees can also have a direct impact on the temperature of the air both inside and outside a building. Fogarty noticed that the air outside a school in west London was being heated up by the ground surfaces outside before it came through the windows. “If you put features such as trees and so on around there, you’re cooling the ground around the building; you get your natural ventilation to work a lot better.” They are likely to improve grades as well; studies have found positive correlations between the presence of trees and academic achievement.
A kind of blue
“Greening cities is good but more radical and more effective is ‘blueing’ cities,” says Nick Cramp, a senior partner at environmental engineering firm Max Fordham. Blueing, in short, means upping the number of bodies of water, which help to cool surrounding areas, increase light levels, and store renewable energy through solar power during the day. “The city of the future should be both green and blue, instead of the unrelenting, exhausting grey of the present day.”
New building design
Ali Shaw, a principal engineer at environmental engineering firm Max Fordham, points out there are cities that have been coping for centuries without electrical intervention. Air conditioning is a relatively new kid on the block. The difference is that some cities were built and adapted in order to withstand severe heat. London is like a polar bear: it was never designed to be all that warm.
We can’t quite scrap London and start again. But, ideally, the work to build a cooler city, not just modify the one we have, begins before the buildings are even constructed. Håvard Haukeland, who co-founded Spacemaker AI to help architects design buildings with the micro-climate in mind, thinks we will see more irregularly shaped buildings in London’s future. “The design of the cooler city will be different, definitely,” he says. Get ready for some weird shapes that will transfer heat in different ways.
What’s required is a “holistic” approach to such design, says Colin Rees, who is the divisional head of consultancy for IES, a company whose building simulation program tells customers how a building might cope with a year’s worth of weather. IES modelled places including the Royal London Hospital and London Heathrow Terminal 5. On the continent, says Rees, windows are protected from harsh sunlight via external shading like shutters, canopies and overhangs. He predicts that the glass facades of the future will have a lot more of these “shading solutions”. One could be Gauzy, a smart film that can use electricity to turn glass opaque in order to cool buildings down.
There will be no silver bullet when it comes to bringing London’s fever down. But, with a combination of modelling, ground source heat pumps, external shading, solar collectors, wind turbines and thousands of trees, there is a great deal of hope in the capital’s future.
If it continues on the right track, London should be able to keep its cool.
