Ever heard of phase-change materials? They may have a complicated-sounding name, but these compounds could offer a serious avenue of pursuit in the quest to keep cool in heatwave conditions. This is because their properties can be used to delay the penetration of heat into our homes. A Korean research team has now found a technique that makes this technology even more effective, by injecting bubbles.
Phase-change materials may sound incredibly technical -- like a physics or chemistry student's worst nightmare -- but these so-called PCMs could help us to better manage heatwave conditions as well as spells of very cold weather. They may sound too good to be true but, in reality, the solution is found right under our noses, in the natural world.
These new materials are, in fact, made from fatty acids and plant-based derivatives, but they can also take the form of sugars or waxes, paraffin oil being the best example from the construction sector. Their advantage resides in their ability to store heat and release it later. Concretely, when these materials transition from a solid state to a liquid state -- in other words, they melt -- they absorb excess heat. This happens at temperatures of 19°C to 27°C, depending on the material. When the ambient temperature drops, the compounds then return to the solid state, making good use of the accumulated heat.
Estimates suggest that peak temperatures in rooms could be reduced by 3°C to 4°C by using PCMs directly in the concrete bricks or plaster used to build homes. This new way of designing walls could help to reduce the use of air conditioning -- which is good news for the environment -- and, above all, reduce the need for heating.
Adding bubbles could improve performance
Scientists at the Korea Institute of Science and Technology recently published research that could help make this technology even more effective. Since the molecules in phase-change materials don't all turn into liquid at the same time, heat still has a means of penetrating into buildings. To solve this, the scientists had the idea of injecting bubbles into the material to encourage uniform melting. This helps keep buildings cool or warm even more effectively.