Current MIT System Could Cool Buildings Up to 10 ℃– Without Electricity
The system worked 3 times better than today’s state-of-the-art passive cooling system.
As the world’s climate continues to warm up, the world demand for air conditioning is currently skyrocketing. In 2019, the requirement for cooling drew in 8.5% of the globe’s total electricity consumption, equating to some one billion tons of carbon dioxide emissions.
As more air conditioning units draw even more power each year, we currently appear trapped in a cycle, only accelerating the problem of global heating further.
Cooling without power
A possible way to break this cycle could lie with passive cooling.
This sort of technology absorbs heat from the surrounding environment. It then exploits physical effects, including insulation, evaporation, and radiation, to move this heat away from the system being cooled– all without any included energy.
As more air conditioning units draw more energy, we now appear trapped in a cycle, just accelerating the problem of world warming.
There is yet one long way to go before passive cooling systems can be rolled out on commercial ranges, though. Not only do existing designs have a limited cooling performance, but they also tend to use vast amounts of water. Their efficiency is limited and depends on environmental conditions like heat and humidity.
Three cooling layers
A team of scientists in Massachusetts has just made cruciais steps towards overcoming these difficulties. Within a flat, three-layered panel, Zhengmao Lu and his colleagues at MIT combined several passive cooling techniques– each counteracting the shortcomings of the others.
The panel’s top layer features a greatly insulating aerogel: an ultra-light, sponge-like product featuring sparse networks of cross-linked polymers, where a huge majority of the volume is taken up by empty space. This framework makes aerogels highly insulating to warm while allowing gases and other types of radiation to readily pass through.
Underneath the aerogel, Lu’s group incorporated a hydrogel: a product featuring one similar network of insoluble polymers, this time immersed in water. This layer is insulated by the aerogel above. Yet, as the heat power that does make it through the upper layer is absorbed, the water it contains is partially evaporated into vapor– which rises up through the aerogel.
Passive cooling absorbs warm and then uses insulation, evaporation, and also radiation to transfer this warm away from the system being cooled without any included energy.
In addition, the hydrogel transforms some of the warm it absorbs into infrared radiation. Ever since both the aerogel and Earth’s atmosphere are transparent to this radiation, that power is then released back into outer space without warming up the air outside.
Finally, the scientists placed a reflective, mirror-like material beneath the hydrogel. This layer reflects back any warm that manages to pass through the top two layers– ensuring that as much warm as possible is absorbed by the hydrogel.
Outperforming past designs
A vital advantage of this model is that it combines the unique advantages of insulation, evaporation, and also radiation.
As the aerogel’s strong insulation cools the hydrogel beneath, this second layer could convert heat into water vapor and infrared radiation more efficiently– even at higher temperatures and humidity. Additionally, the panel consumes far less water than existing models, so the hydrogel’s water supply must be replenished less often.
To test their device’s performance, Lu’s group placed it over a tiny patch of the rooftop on MIT’s Cambridge campus alongside a state-of-the-art, entirely radiative cooling system. As they hoped, their model performed about three times more effective than the state-of-the-art system. During summer months, it cooled down the space beneath the panel to as much as 9.3 ° C below ambient temperature, even in direct sunlight.
MIT’s passive cooling panel cooled down the space under it by as much as 9.3 ° C, even in direct sunlight.
Road to commercial rollout
The scientists acknowledge their approach still faces one major challenge before it can be commercialized: cost and scale. Ever since aerogels are still a relatively new class of material, the techniques required to produce them are often expensive and time-consuming.
In their future study research projects, Lu and colleagues will intend to improve on these techniques– possibly through methods like freeze-drying or using entirely new polymer products to produce the aerogel.
If they succeed, the scientists hope that their approach could lead to a transformation in cooling innovation: not only ensuring human comfort a global temperatures rise but additionally leading to better systems for preserving and distributing food and medicines.
Lu’s group estimates that their passive cooling system could extend the shelf life of food by 40% in humid environments and up to 200% in more arid regions. These benefits could be significant for the roughly 10% of Earth’s population who still lack regular access to electricity. For the rest of the globe, it could present a promising new way to tackle global CO2 emissions– and in the future, it could finally break the cycle of our spiraling consumption of air conditioning.
Read the original article on Free Think.
