The world now has a new, environment-friendly heating and cooling technique 

If you live somewhere where it snows during winter, you would know the art of salting roads. Turns out, when salts are scattered on the streets prior to a snowfall, it helps melt the snow that otherwise block the roads. But how on earth does salt melt snow? Well, when salt is added to water, it gets harder and slower for the water molecules to freeze. So, instead of freezing at the usual 0°C, the freezing point further drops to -9.4°C. This means that when snow hits the ground surface already treated with salt, the area would only freeze if the temperature outside dropped further. Isn’t that cool?  

Well, recently, researchers based at the Department of Energy of Lawrence Berkeley National Laboratory, USA, used this basic concept (called freezing point depression) to develop a brand-new method of heating and cooling. Named the ‘ionocaloric cooling’, this technique takes the advantage of energy, such as heat, that is stored or released when a substance changes its state, such as altering solid ice to liquid water. As we all know, melting absorbs heat from the atmosphere while solidifying releases heat. Guess what this ionocaloric cooling does? It allows the change of state and temperature to flow through ions (electrically charged atoms) which as it happens, comes from a salt.  

Sources cite that this technique has the potential to be so much efficient that it can easily replace the existing “vapour compression” system used by home refrigerators. For those unaware, vapour compression uses greenhouse gases with high climate change potential, such as HFCs or hydrofluorocarbons. If this ionocaloric cooling is incorporated into modern-day refrigerators, it would reduce the risk of such toxic gases escaping into the atmosphere by simply replacing them with solid such as salts or liquids such as brine solution.  

Experts have said that the world of refrigerants is still looking for an alternative solution that will be environment friendly, is safe, works efficiently and above all keeps things cold. And it looks like using the method of ionocaloric cooling is the ultimate way forward as it meets all the criteria properly. In fact, this will also help mitigate climate change as HFCs (also present in air conditioners) often trap heat thousand times more than carbon dioxide.  

Projects like Kigali Agreement (introduced in October 2022 and has 145 parties including the USA) that aims to reduce production and consumption of HFCs by 80 percent in the next 25 years should thus make this brand-new heating and cooling system a key to solve their problem.  

In addition, ionocaloric cooling can also further other methods such as magnetism, change of pressure zones, and shift in electric fields – all of which require solid to liquid shifts but often end up releasing unwanted gases. It will also advance industrial heating and water heating in general. 

What’s more interesting is that the process can use organic solvents like ethylene carbonate in place of rock salts which not only has zero global warming capacity, but negative. Okay, but what does this mean? This means that it will not just not release carbon into the atmosphere but also use its compound such as carbon dioxide from the atmosphere as producing ethylene carbonate requires high amounts of CO2. 

The study has been published in the journal Science while the team involved has applied for a patent for “ionocaloric refrigeration cycle.” The project was also part of USA’s Energy Efficiency and Renewable Energy Building Technologies Programme.