Nanoparticle-infused oil could improve transformer cooling

A new nanoparticle-infused oil could increase the heat-shedding efficiency of transformers and microelectronic components by 80 per cent.

The specially engineered boron nitride particles are electrically insulating as well as highly dispersant.

Electrical transformers are filled with fluids that cool and insulate the core and windings inside, as well as components that must remain separated from each other to keep voltage from leaking or shorting.

‘Thermal management is a big issue in industry, but the right choice of materials is important; for transformer cooling, one needs dispersants in oils that take heat away, yet remain electrically insulating,’ said project lead Prof Pulickel Ajayan of Rice University.

The team discovered that a very tiny amount of hexagonal boron nitride (h-BN) particles — two-dimensional cousins to carbon-based graphene — suspended in standard mineral oils are highly efficient at removing heat from a system.

The h-BN particles, about 600nm wide and up to five atomic layers thick, disperse well in oil and, unlike highly conductive graphene, are highly resistant to electricity. At a 0.1 weight percentage of h-BN, the transformer oil’s heat-shedding efficiency was enhanced by nearly 80 per cent.

‘And at 0.01 weight percentage, the enhancement was around nine per cent,’ said project collaborator Jaime Taha-Tijerina. ‘Even with a very low amount of material, we can enhance the fluids without compromising the electrically insulating properties.’