Air conditioners are the most energy-consuming domestic appliances. According to the latest data, by simply replacing the refrigerants that damage the atmosphere, we could reduce greenhouse gases by the equivalent of 90bn tonnes of CO2 by 2050. And making all units more energy-efficient could double this number. The effects of many good environmental practices can’t even compare to that.

Here are some examples: if two thirds of all the tropical forests that we have destroyed were to be replanted, we could save “just” 61bn tonnes of CO2. And if half of the global population stopped eating meat, it could save “just” 66bn tonnes of CO2.  Then, there is an important cultural fact: while cars are globally recognized as a major cause of global warning, air conditioning often slips under the radar, even though it triggers a vicious circle: the higher the temperatures, the more air conditioning we use, the more damages we cause. And keeping plants inside our homes doesn’t help. We would need entire forests to control temperature and pollutants in the cities. What’s more, not all plants are the same: botanists urge the creation of parks full of C3 and C4 plants as to reduce CO2 emissions. 

Apart from that, in May, a team of researchers from the National University of Singapore has presented the prototype of a new air conditioner capable of cooling the air by using water. This air conditioner, which is still at an experimental stage, can reach a temperature as low as 18 °C, without energy-intensive compressors and environmental harmful refrigerants. By solving two problems in one, it sounds like the Columbus egg. But that’s not all: this air conditioner is portable, so it is suitable for both indoor and outdoor use, and it generates from 12 to 15 litres of drinking water every day. The only downside is that it is still a prototype.  It is still not for us to know if the product will ever be commercialized.

This new air conditioning system focuses on the three key issues in air conditioning on which many other companies and research centres all over the world are now concentrating. First, the new system   is trying to reduce energy consumption and make all the devices more efficient, in order to consume less energy. Second, it’s trying to overcome the 100-year-old technology we are still using: for over a century air conditioners have been removing air from the outside, and maybe it’s time to change that, because while chilling indoor air, they blow hot air back outside. Third, they are trying to find climate-friendly alternatives to refrigerants.  In particular, they are fighting against hydrofluorocarbons, the so-called HFCs, which are a thousand times worse than CO2 in preventing heat from leaving the planet. Luckily, thanks to the Kigali Amendment to the Montreal Protocol (which was ratified on June 3rd) the use of HFCs will be reduced. 

A more systemic viewpoint, so to speak, comes from the researchers of the Karlsruhe Institute of Technology (KIT) and the University of Toronto: in the article “Crowd oil not crude oil” published last April in Nature Communications, they address the problem of air conditioning from a completely new perspective. Their project is to exploit already existing air conditioning systems to generate clean (zero-emission) fuels. Through specific chemical processes, water and CO2 generated by air conditioners can become a synthetic fuel to be used in transports or for other industry applications. As the title of the research suggests, we could move to a distributed production of fuels (crowd oil) as it has already been done for renewable energy. However, for now, it remains merely a suggestion.

Photo Courtesy: Sergei Akulich