Copper nanotubes significantly boosts boiling efficiency

Think what this could do for oil sands extraction or country wide central heating like in Sweden, Ukraine or Russia.

If you can boil water using 30 times less energy, that's 30 times less energy you have to pay for, conclude researchers.

A scanning electron microscope shows copper nanorods deposited on a copper substrate. Air trapped in the forest of nanorods helps to dramatically boost the creation of bubbles and the efficiency of boiling, which in turn could lead to new ways of cooling computer chips as well as cost savings for any number of industrial boiling application.  Credit: Rensselaer Polytechnic Institute/ Koratkar

Whoever penned the old adage "a watched pot never boils" surely never tried to heat up water in a pot lined with copper nanorods.

Researcher at the Rensselaer Polytechnic Institute in the USA have shown that by adding an invisible layer of the nanomaterials to the bottom of a metal vessel, an order of magnitude less energy is required to bring water to boil.  This increase in efficiency could have a big impact on cooling computer chips, improving heat transfer systems, and reducing costs for industrial boiling applications.

"Like so many other nanotechnology and nanomaterials breakthroughs, our discovery was completely unexpected." said Nikhil A. Koratkar, associate professor in the Department of Mechanical, Aerospace, and Nuclear Engineering at Rensselaer, who led the project. 

"The increased boiling efficiency seems to be the result of an interesting interplay between the nanoscale and microscale surfaces of the treated metal.  The potential applications for this discovery are vast and exciting, and we're eager to continue our investigations into this phenomenon."

"By themselves, the nanoscale and microscale textures are not able to facilitate good boiling, as the nanoscale pockets are simply too small and the microscale cavities are quickly flooded by water and therefore single-use. But working together, the multiscale effect allows for significantly improved boiling.  We observed a 30-fold increase in active bubble nucleation site density - a fancy term for the number of bubbles created - on the surface treated with copper nanotubes, over the nontreated surface."

Boiling is ultimately a vehicle for heat transfer, in that it moves energy from a heat source to the bottom of a vessel and into the contained liquid, which then boils, and turns into vapor that eventually releases the heat into the atmosphere.  This new discovery allows this process to become significantly more efficient, which could translate into considerable efficiency gains and cost savings if incorporated into a wide range of industrial equipment that relies on boiling to create heat or steam.

Source: Rensselaer Polytechnic Institute

Comments

[Silverthorn]

This story is nonsense. Or, at least, talk of using 30 times less energy to boil water is nonsense. The minimum amount of energy needed to boil water is set by hard thermodynamic limits; the actual amount needed in practice is not far above the thermodynamic minimum. (I.e., in a well-designed boiler, the amount of heat wasted is small compared to the heat used in converting water to steam.)

I've no doubt that nanotechnology has some potential for improving the efficiency of heat exchangers. That may well be important for improving the efficiency of various chemical processes. It would also help to improve the efficiency of various heat engines, by reducing temperature drops across heat exchangers. But the improvements will be incremental, not revolutionary.