August has just ended and the damage of yet another record heat can be seen everywhere. Heat waves and fires are a well-known leitmotif, to which the collapse of electricity grids is gradually added. Thousands and thousands of families "in the dark" due to the effects of energy overload.
Periodic blackouts offer only a small hint of what is likely to happen in the future. Population growth, urbanization and summer temperatures will triple the number of air conditioners installed worldwide by half a century. The total of air conditioners goes towards 6 billion, according to the International Energy Agency's Future of Cooling report.
Air conditioning represents one of the most insidious challenges of climate change and one of the most difficult technological problems to solve.
It's obvious: the warmer the world, the more we need cooling
It is not just a matter of comfort, but of health and survival in much of the world. Yet air conditioners themselves produce enough heat to measurably raise urban temperatures and increase greenhouse gases.
Billions of new power-hungry units will create a surge in one of the largest sources of electricity demand worldwide.
Without major improvements, the demand for energy from cooling will also triple, reaching i 6.200 terawatt hours by 2050, or nearly a quarter of the total electricity consumption in the world today.
54,4 ° Celsius (130 degrees Fahrenheit). It is the highest temperature ever recorded on Earth. And it was recorded last month, in Death Valley in California. Do we want to continue like this? And help out in the heat?
Air conditioner technology is at a standstill
I see little progress in the sector. Aside from small efficiency gains, the core technology of air conditioners works much like when it was introduced nearly a century ago.
“The fact that air conditioner use continues to increase while the product largely looks the same as it did decades ago speaks for itself,” he says Romanin wins, CEO of Treau, a San Francisco-based startup developing a new type of heat pump.
“I think a lot of people would be excited about a change, but there's only been incremental progress,” he says. And she's right.
In recent decades, there have been far greater improvements in other energy technologies (solar panels, batteries and electric vehicles) thanks to public opinion and state intervention. Treau is one of several startups and research groups that are now trying to make progress on cooling.
It may not be enough
Even if the global stock of air conditioning units becomes much more efficient, the expected jumps in use are so large that global electricity demand will continue to rise. This will complicate the already prohibitive task of cleaning up the world's energy sectors. It means nations must not just overhaul existing electricity infrastructure: they must build much larger systems than have ever existed and do it all with renewable or emissions-free sources.
Cooling the large volumes of hot air that fill homes, offices and factories is, and always will be, a huge energy consumption.
The problem isn't just that more air conditioners will require more and more electricity to power them. It is that it will especially increase the amount needed during peak hours, when temperatures are really hot. A problem already known as “duck curve” which will also be caused from the refills of electric cars. Everyone will tend to recharge at night, everyone will turn on their air conditioning during the hottest hours. We must overbuild electrical systems to meet demand levels that may only occur for a few hours or days a year.
Watch out for India
The world will see much greater increases in the demand for air conditioners in nations where the middle class is rapidly expanding, and where heat waves will become more common and severe. In particular India is expected to install an additional 1,1 billion units by 2050, increasing the share of air conditioners in the nation's peak electricity demand from 10% to 45%.
How can this be solved?
Clean energy - The most crucial action must take place on the electricity grid as a whole. We need greater use of clean energy sources, such as solar and wind, to reduce indirect greenhouse gas emissions resulting from the use of air conditioners.
Smart grids – the development of increasingly intelligent grids could help electricity systems cope with peaks in demand for alternating current. This involves adding sensors, control systems and software. Systems capable of automatically reducing use as the external temperature decreases or when people leave the spaces for long periods.
Fresh alternative – The world can also reduce air conditioning emissions by switching to alternative refrigerants. Manufacturers have largely relied on hydrofluorocarbons, very potent greenhouse gases that can escape during manufacturing and repair or at the end of a unit's life.
Under a 2016 amendment to the Montreal Protocol, companies and countries must increasingly shift to lower-impact options. There are some promising compounds known as HFOs, some hydrocarbons like propane, and even carbon dioxide (which at least has less of a heating effect than existing refrigerants).
Alternative refrigerants could reduce emissions by the equivalent of approximately 50 billion tons of carbon dioxide over the next few decades.
Above all, efficiency
Beyond these solutions, the growing number of air conditioners operating in homes and buildings around the world must become much more energy efficient.
The technology to do this is already there: The best available technology is more than twice as efficient as the products actually in use in the world and three times better than the most inefficient products on the market.
The problem is that most people and businesses will not pay much more for more efficient systems “just” to help meet global climate goals, particularly in poor areas of the world.
Incentives or subsidies could help ensure the deployment of more efficient products
The effects? Obvious
In the IEA scenario that includes these good policies, the increase in cooling-related energy consumption would be reduced by 45% by mid-century.
Even then, however, energy demand would still increase by about 70% by mid-century.
Achieving significant additional gains may require more radical changes.
Radical changes
Several startups are trying to push things further.
Transaera, co-founded by the MIT professor of energy Mircea Dinca, is attempting to significantly improve the efficiency of air conditioners.
In addition to cooling the air, conventional units dedicate enormous amounts of energy to dealing with water vapor, which traps heat. This requires lowering the temperature well beyond what is read on the air conditioner display. Only in this way can the vapor be converted into a liquid and removed from the air.
“It's incredibly inefficient,” he says Dinca, “It's a lot of energy and it's not necessary.”
Transaera's approach is based on a class of highly porous materials. They are known as metal-organic frameworks, and can be optimized to capture specific compounds, including water. Transaera has developed an accessory for air conditioning systems that uses these materials to reduce moisture in the air before it enters an air conditioner. The company estimates that this system improves overall energy efficiency by more than 25%.
Other research in progress
La SkyCool Systems of Mountain View, California, has developed high-tech mirrors that can project heat into the cold expanses of space, exploiting a natural phenomenon known as radiative cooling.
Placed on rooftops, these devices can replace or augment traditional building cooling systems. The company estimates that the technology can reduce the energy used to cool structures by 10 to 70%, depending on configuration and climate. SkyCool is installing the materials on its fourth commercial site.
Other startups are exploring ideas such as ground source heat pumps, solid-state technologies that avoid the need for refrigerant gases, and new cooling modifications.
