Take a look at these building facades in Singapore. And these in New Delhi, New York and Hong Kong. Notice anything? In these parts of the world, life without air conditioning can be uncomfortable – or downright dangerous. "More than a dozen people have died in India in the past two months due to a severe heatwave." "A fierce heatwave." "Heatwaves." "Heatwave." But that brings us to our dilemma. The technology needs lots of energy. In fact, cooling buildings accounts for 10% of our global electricity consumption. And that's bad news for global warming. "It's a vicious loop. We cool the indoors, but we warm the outdoors, therefore generating the need for more cooling." But there are solutions – some traditional, some modern – that don't eat up massive amounts of energy. So... can they help us break out of this vicious circle? The story behind this conundrum begins in New York City in 1902. That's where the engineer Willis Carrier laid the foundations for the modern air conditioner. He designed an engine to control the humidity in a printing plant because it was warping the paper. Simply speaking: the system blew air over coils filled with cool water. Not only did the humidity condense on these coils, but the air in the plant also became comfortably cool. Over the next decades, more developed versions of the primitive system made it into businesses and later into American homes. "This lucky baby will sleep quietly through the night..." Suddenly resting, working, living during hot weather was not only possible – it could be pleasant. Nowadays, Americans are still some of the most prolific AC users globally. 90% of US households own an air conditioner. In some of the hottest parts of the world, it's not even 10%. But other countries want to catch up. Just look how much more energy some of these emerging economies are projected to use in the coming decades to cool their homes and buildings. This is 2016
and this is 2050. "If you see India's air conditioning market, it is growing in double digits." Ankit Kalanki is working to open up the global market for high-efficiency air conditioners. "India's population is growing. India is getting even hotter. But also a large portion of the Indian population is urbanizing, is moving to cities. And all of that together constitutes a huge demand for air conditioners." Because of trends like these, global energy demand for space cooling is projected to triple by 2050. The question is how to meet the soaring demand without exacerbating the heat. Because, in much of the world, the energy-guzzling technology is powered by fossil fuels. These emit lots of greenhouse gases, which make the atmosphere hotter. And nowadays ACs have refrigerants running through their coils to absorb heat from the warm air. Some of them are literal greenhouse gases. You don't want those leaking out of your unit.
On top of that, air conditioners cool indoor spaces by pushing out the heat that refrigerants absorb. That means they make the immediate surroundings hotter, too. And people who can't afford ACs suffer most from that. "So we've got a threefold effect as a result of air conditioning on the atmosphere and being able to reduce it down to either efficient cooling or doing cooling without air conditioning is really a smart solution to get there." This is Prasad Vaidya, an expert in passive solar design. He says there are three steps to cooling sustainably. First, we need to reduce heat at a city-wide scale because: "That is access for everybody." You may have heard of the urban heat island effect. It's when urban areas like these get warmer than their surroundings because all this concrete absorbs and retains heat. And there is also lots of waste heat from human activities like transport or well, air conditioning. Creating more spaces with shady trees and other plants lessens this effect. Like here in Berlin. The Colombian city of Medellin was able to reduce average temperatures by 2°C only three years after planting green corridors. The interconnected network of greenery spans dozens of waterways and busy, polluted streets. And minimizing heat expelled by cars also makes a difference. In Spain, Barcelona's superblocks prioritize pedestrians and cyclists. But scale matters. The city's Institute for Global Health estimates that 117 heat-related deaths could be avoided every year if hundreds more blocks were introduced. The next step is designing buildings that aren't as reliant on air conditioners. And this is where we can really learn from traditional architecture. "Before technology, all people around the world found solutions to survive properly." Charles Gallavardin leads bioclimactic architecture projects in countries like Vietnam and Mauritania. That means the designs take local climates into account. "So we have to study this vernacular architecture carefully." Some modern buildings are already doing this. Such as Qatar University, which uses wind towers to keep its buildings cool. This method has been used in Iran and other Middle Eastern countries for centuries. The so-called wind catchers are designed to trap fresh air and direct it indoors. The hot air gets pushed out. You may also have noticed that houses in hot climates are often white. Some countries like India are bringing back this approach by painting roofs with lime-based white-wash which absorbs less heat. This can reduce indoor temperatures by 2°C to 5°C. When designing new buildings, bioclimatic architects tend to combine different sources of inspiration. But they will all tell you: location is everything. "You have to pay attention to the sun orientation and make sure your facades are not exposed to the direct sun. And then we usually study carefully the wind direction." Knowing the wind direction is important to design openings that encourage cross ventilation. Other features that can help stave off heat are shading devices that keep the facade cool. And insulation prevents heat from traveling through your roof, for example. Gallavardin says these methods
can reduce indoor temperatures by about 5°C – while ceiling fans can help circulate this cooler air. ACs may still need to be used sometimes. But to a much lesser extent. The problem? In many countries going through a construction boom, new buildings often look like this. "Builders tend to build them with floor to ceiling glass. And that's a real problem because every time you put glass into a building, you turn it basically into a hotbox. It's like a solar cooker." Architects and engineers say this aesthetic is popular because it's perceived as sleek, modern and lets in natural light. Changing that would require more rigorous building regulations around energy efficiency. And a massive cultural shift to actually get them enforced on the ground. "In most of the architecture schools, it's still not... we are not trained for this." "When you ingrain that into their sort of business as usual approach, you will get the solutions." Another big obstacle is that this approach tackles new constructions. But what about all the old, badly insulated buildings that already exist? This takes us to our next solution: more efficient air conditioning. Because there is no technological reason for ACs to use as much energy as many commercial models do now. "The AC industry is rooted in a roughly hundred year-old technology. It's been working. Convenient. At the switch of a button, we get cooling." This is Sneha Sachar. She works to make climate-friendly cooling more accessible. "There hasn't been a lot of motivation or market factors that have spurred innovation." And you really see how wasteful ACs can be in places like India, Singapore or parts of the US. Because this is where it often gets humid. "About a third of the energy is used for managing humidity." While some modern models have a so-called dry mode to target humidity, Kalanki says air conditioners are still pretty bad at measuring how much moisture is in the air. And consequently, how much moisture they need to remove for optimum comfort. So: many people simply blast their ACs to overcool the room and get humidity down to the desired level. In 2018, an innovation competition called the Global Cooling Prize showed that there are ways around this. RMI, a US non-profit dedicated to sustainable energy use, cooperated with the Indian government and a global iniative called Mission Innovation to elect two winning teams. "They used better controls, they had better sensing capabilities, and they were able to sense both the temperature and the humidity. And that's how they were able to optimize the performance of an air conditioner." Paired with other technological improvements, the two groups came up with models that had a five times lower climate impact. Kalanki says one of the teams wants to put its unit on the market in 2025. But that comes with a set of challenges. The market's testing standards need to be updated so the performance review takes into account how efficiently the air conditioner controls humidity. Large buyers also need to come on board to bring down the cost. And consumers need to be incentivized to buy more efficient models, even though the sticker price may be higher. "While the more efficient air conditioners are costlier upfront, you will save much more energy over the ten year lifetime of that air conditioner. And therefore, the total cost of ownership is about half of the standard products. But that's where the challenge lies. Either consumers don't have that financial ability to spend that money upfront or they are just not aware about it." But what if we thought about efficient, mechanical cooling on a much larger scale? A system like this is already functioning in Singapore. Here, an underground air conditioner, touted as the largest in the world, cools residential buildings, banks, malls and this iconic hotel. The technology is called district cooling and it can save up to 50% on energy and emissions. That’s because having one big plant cooling an entire district makes it super efficient. The water is chilled 25 meters below the ground before it is piped across different buildings. "The challenge for district cooling is in terms of infrastructure. Right. It's a big capital investment and it requires a lot of infrastructure." Cities like Toronto, Paris and Hong Kong have already taken on the colossal task of cooling dozens of buildings with one system. In some cases, district cooling makes use of networks that already exist. Most of the system in Paris runs through the city's sewage network. But for the most part, district cooling is better suited for new constructions. For example, Gujarat International Finance Tec-City — also known as GIFT City. While building the new, hyper-dense Indian district, developers had a blank canvas to implement any cooling solution they wanted. Their choice: district cooling. Because it's more efficient and cheaper to maintain. This may sound utopian, but like all other solutions, it requires lots of upfront capital, know-how and of course, awareness. Still, experts say this type of investment is urgently needed — whether it's on a city-wide or neighborhood-scale or in broader technological innovation. Especially in places like India, China and Indonesia where AC usage is projected to soar. "We don't have an option. We don't have enough energy in the world to be able to do all the cooling that's needed, even if we try to do it as a renewable energy." "It feels like slow steps and sometimes they are, but we are certainly making our way towards a better way to cool our built environment." The good news is cooling doesn't always have to look like this. But if we don't move in a more sustainable direction fast enough, we risk staying trapped in a solution that is actually part of the problem. I know I wouldn't have survived the summer without my trusted fan. So I'm wondering: How do you cool your home and would any of these solutions make a difference in your life? Let us know in the comments and don't forget to subscribe to our channel."
