The boiling of water is one of the very first chemical-physical processes that are studied already in school age. So they teach us that water boils at 100 ° C, during the phase of transition from the liquid to the gaseous state: as it heats up, bubbles and steam are formed (evaporation). A process that we see practically every day in our homes, even if only when we have to “put on the pot” to cook pasta.
Yet the boiling of water and fluids in general has to do with a myriad of industrial processes that require a certain amount of energy. Today a new path has opened, which would allow us to save in energy terms by boiling the water faster and all thanks to a new materialdesigned (at the moment) on a smaller scale by MIT in Boston.
The Boston MIT study
“The boiling of water or other fluids is an ad phase high energy intensity at the heart of a wide range of industrial processes, including most power generation plants, many chemical production systems and even cooling systems for electronics. Improving the efficiency of systems that heat and evaporate water could significantly reduce their energy consumption. “Just read the article published on the website of the MIT of Boston to understand the scope of the new study prepared by Dr. Youngsup Song, Ford Engineering Professor Evelyn Wang and their team.
The results, published in the journal Advanced Materials, show that it is possible to specifically treat the materials involved in the boiling process of water and fluids. A result that can be achieved quite simply by maximizing the yield of two fundamental parameters: il heat transfer coefficient (HTC) and critical heat flux (CHF). As Dr. Song explains, there is usually a problem when designing such industrial materials: it’s not possible improve one of the two parameters without worsening the other in terms of efficiency.
But the new research from MIT opens the door to a real revolution. Dr Song explains that “If we have a lot of bubbles on the boiling surface, it means that boiling is very efficient, but if we have too many bubbles on the surface, they can fuse together to form a steam film on the boiling surface“It is this kind of” film “that increases the resistance and prevents the transfer of heat from the hot surface to the water.
A new material
How, then? It seems that MIT has finally found the solution: that’s enough keep the bubbles separate, avoiding the formation of this heat-resistant film that slows the boiling of water or specific fluid. To achieve this, the researchers created a material that has two characteristics in particular. On one side on the surface have been inserted micro-cavity separated at a distance of 2 mm, to block bubbles and prevent the formation of the infamous high-strength film.
But since keeping the bubbles separate also reduces the boiling capacity, they compensated by creating “tiny nubs and ridges at the nanoscalewhich increases the surface area and promotes the rate of evaporation under the bubbles. ”The combination of these elements causes it to exponentially improve the maximum heat flow.
The material thus designed works, but at the moment it has only been tested on a small scale, in a laboratory. We do not know when it will be introduced and adapted to industrial devices, where it would be appropriate to create the conditions for a effective energy saving.