New surface treatment could improve refrigeration efficiency
A slippery surface for liquids with very low surface tension promotes droplet formation, facilitating heat transfer.
Unlike water, liquid refrigerants and other fluids that have a low surface tension tend to spread quickly into a sheet when they come into contact with a surface. But for many industrial processes it would be better if the fluids formed droplets, which could roll or fall off the surface and carry heat away with them.
Efficiency improvements
Now, researchers at MIT have made significant progress in promoting droplet formation and shedding in such fluids. This approach could lead to efficiency improvements in many large-scale industrial processes including refrigeration, thus saving energy and reducing greenhouse gas emissions.
Unlike the surface treatments the scientists have developed for other kinds of fluids, which rely on a liquid material held in place by a surface texture, in this case they were able to accomplish the fluid-repelling effect using a very thin solid coating — less than a micron thick (one millionth of a meter). That thinness is important, to ensure that the coating itself does not contribute to blocking heat transfer.
The coating, made of a specially formulated polymer, is deposited on the surface using initiated chemical vapor deposition (iCVD), in which the coating material is vaporised and grafts onto the surface to be treated.
More information can be found on the Massachusetts Institute of Technology Website.
Image source: Pixabay.
