How to cool our homes (even without ACs)

Take a look at the facades of these buildings in Singapore. And these in New Delhi, New York and Hong Kong. Do you notice anything? In these parts of the world, life without air conditioning can be uncomfortable or

even

dangerous. "More than a dozen people have died in India in the last two months due to a severe heat wave." "A fierce heat wave." "Heat waves." "Heat wave". But that brings us to our dilemma. Technology needs a lot of energy. In fact, building

cool

ing accounts for 10% of our global electricity consumption. And that's bad news for global warming. "It's a vicious cycle.

We

cool

the inside, but we heat the outside, thus generating the need for more cooling." But there are solutions (some traditional, some modern) that do not consume enormous amounts of energy. So... can you help us get out of this vicious circle? The story behind this enigma begins in New York City in 1902. That is where engineer Willis Carrier laid the foundations of modern air conditioning. He designed a motor to control humidity in a printing press because it warped the paper. Simply put: the system blew air over coils filled with cold water. Not only did moisture condense on these coils, but the air in the plant was also comfortably cooled.

Over the next few decades, more developed versions of the primitive system reached businesses and later American

homes

. "This lucky baby will sleep peacefully all night..." Suddenly, resting, working, and living during the heat was not only possible, it could also be enjoyable. Today, Americans remain some of the most prolific air conditioning users in the world. 90% of American

homes

have air conditioning. In some of the hottest parts of the world, it is not

even

10%. But other countries want to catch up. Just look at how much additional energy some of these emerging economies are expected to use in the coming decades to cool their homes and buildings.

It's 2016 and it's 2050. "If you look at the Indian air conditioning market, it is growing in double digits." Ankit Kalanki is working to open the global market for high-efficiency air conditioners. "India's population is growing. India is getting even hotter. But also a large part of the Indian population is urbanizing, moving to cities. And all that together constitutes a huge demand for air conditioners" . Due to trends like these, global energy demand for space cooling is expected to triple by 2050. The question is how to meet the growing demand without exacerbating the heat. Because, in much of the world, energy-intensive technology runs on fossil fuels.

These emit many greenhouse gases, which warm the atmosphere. And today, air conditioners have refrigerants that circulate through their coils to absorb heat from hot air. Some of them are literally greenhouse gases. You don't want them to leak out of your unit.   In addition to that, air conditioners cool interior spaces by expelling the heat absorbed by refrigerants. That means they also make the immediate environment warmer. And people who cannot afford air conditioning suffer the most from this. "So we have a triple effect as a result of air conditioning in the atmosphere and being able to reduce it to efficient cooling or cooling without air conditioning is really a smart solution to achieve that." This is Prasad Vaidya, an expert in passive solar design.

He says there are three steps to sustainably cooling. First, we need to reduce heat on a city-wide scale because: "That's access for everyone." You may have heard of the urban heat island effect. This is when urban areas like these become warmer than their surroundings because all this concrete absorbs and retains heat. And there's also a lot of waste heat from human activities like transportation or, well, air conditioning. Creating more spaces with shade trees and other plants reduces this effect. Like here in Berlin. The Colombian city of Medellín was able to reduce average temperatures by 2°C just three years after planting green corridors.

The interconnected network of vegetation spans dozens of busy, polluted waterways and streets. And minimizing the heat expelled by cars also makes a difference. In Spain, Barcelona superblocks give priority to pedestrians and cyclists. But scale does matter. The city's Institute for Global Health estimates that 117 heat-related deaths could be avoided each year if hundreds more blocks were introduced. The next step is to design buildings that are not as dependent on air conditioning. And this is where we can really learn from traditional architecture. "Before technology, everyone in the world found solutions to survive properly." Charles Gallavardin leads bioclimatic architecture projects in countries such as Vietnam and Mauritania.

That means designs take local climates into account. "So we have to study this vernacular architecture carefully." Some modern buildings are already doing this. Like 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 is expelled. You may also have noticed that houses in warm climates are usually white. Some countries like India are bringing back this approach by painting roofs with lime-based whitewash, which absorbs less heat.

This can reduce the indoor temperature by 2°C to 5°C. When designing new buildings, bioclimatic architects tend to combine different sources of inspiration. But everyone will tell you: location is everything. "You have to pay attention to the orientation of the sun and make sure that the facades are not exposed to direct sun. And then we usually carefully study the direction of the wind." Knowing the direction of the wind is important to design openings that encourage cross ventilation. Other features that can help prevent heat are shading devices that keep the façade cool. And the insulation prevents heat from passing through the roof, for example.

Gallavardin says these methods can reduce indoor temperatures by about 5°C, while ceiling fans can help circulate this cooler air. It may still be necessary to use air conditioning at times. But to a much lesser extent. The problem? In many countries experiencing 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 in a building, you basically turn it into a hot box. It's like a solar cooker." Architects and engineers say this aesthetic is popular because it is perceived as sleek, modern and lets in natural light.

Changing that would require more rigorous building regulations around energy efficiency. And a massive cultural change to really apply it on the ground. "In most architecture schools, we're still not... we're not trained for this." “When you incorporate that into your regular approach, you will get the solutions.” Another big obstacle is that this approach addresses new construction. But what about all the old, poorly insulated buildings that already exist? This brings us to our next solution: a more efficient air conditioner. Because there is no technological reason for air conditioners to consume as much energy as many commercial models now. "The air conditioning industry has its roots in technology that's about a hundred years old.

It's been working. It's convenient. With the push of a button, we get cool." This is Sneha Sachar. She works to make climate-friendly refrigeration more accessible. "There hasn't been a lot of motivation or market factors that have spurred innovation." And you really see how wasteful air conditioners can be in places like India, Singapore or parts of the US because this is where it tends to be humid. "About a third of the energy is used to manage humidity." While some modern models have a so-called dry mode to monitor humidity, Kalanki says air conditioners are still pretty bad at measuring how much humidity is in the air.

And, consequently, how much moisture they must remove to achieve optimal comfort. So: many people simply blow up their air conditioners to cool the room too much and reduce the humidity to the desired level. In 2018, an innovation competition called the Global Cooling Prize showed that there are ways to solve this problem. RMI, an American nonprofit dedicated to sustainable energy use, cooperated with the Indian government and a global initiative called Mission Innovation to choose two winning teams. "They used better controls, they had better sensing capabilities, and they were able to sense both temperature and humidity. And that's how they were able to optimize the performance of an air conditioner." Along with other technological improvements, the two groups came up with models that had five times less climate impact.

Kalanki says one of the teams wants to put its unit on the market in 2025, but that comes with a number of challenges. Market testing standards need to be updated so that the performance review takes into account how efficiently the air conditioner controls humidity. Large buyers must also join in to reduce the cost. And consumers need to be incentivized to buy more efficient models, even though the sticker price may be higher. "While more efficient air conditioners are more expensive up front, you will save much more energy over the ten-year life of that air conditioner. And therefore, the total cost of ownership is about half of standard products.

But that's where the challenge lies. Either consumers don't have the financial ability to spend that money up front or they're just not aware of it." But what if we thought about efficient mechanical refrigeration on a much larger scale? A system like this is already working in Singapore. Here, an underground air conditioner, considered the largest in the world, cools residential buildings, banks, shopping centers and this emblematic hotel. The technology is called district cooling and can save up to 50% in energy and emissions. This is because having a large plant that cools an entire district makes it super efficient.

The water is cooled 25 meters underground before being channeled through different buildings. "The challenge for district cooling is in terms of infrastructure. Right. It's a big capital investment and 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 a single system. In some cases, district cooling uses networks that already exist. Most of Paris' system runs through the city's sewer network. But for the most part, district cooling is best suited for new construction. 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. Your choice: district cooling. Because it is more efficient and economical to maintain. This may seem utopian, but like all other solutions, it requires a lot of initial capital, knowledge and, of course, awareness. Still, experts say this type of investment is urgently needed, whether on a city-wide or neighborhood scale or in broader technological innovation. Especially in places like India, China and Indonesia, where air conditioning use is expected to increase. "We don't have a choice. We don't have enough energy in the world to be able to do all the cooling that is needed, even if we try to do it as renewable energy." "They seem like slow steps and sometimes they are, but we are certainly moving toward a better way to cool our built environment." The good news is that cooling doesn't always have to be this way.

But if we don't move in a more sustainable direction quickly enough, we risk becoming 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 wonder: How do you cool your house? 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."