[nanoPost] Nanofluids for Improved Heat Transfer

Company USA

The concept of adding particulate solids to liquids to increase the heat transfer of the liquid is well known. While studies go back to Maxwell in the 1800’s, the practical execution has been limited by the unavailability of suitable small size particles. Some problems when using larger particles include precipitation of the particles out of solution, clogging of fluid channels, and abrasion of wetted pumping components. 

One area where the availability of increased heat transfer fluid performance would have immediate benefits is the automotive coolant business. Worldwide, this is about a 4 billion euro per year business; and of course, any company able to increase the efficiency of coolants could share in the value created.

One potential method to increase the efficiency of automotive coolant, or for that matter any heat transfer fluid, is with nanofluids. Nanofluids are fluids with nanoparticles, particles with length scales on the order of nanometres, 10-9m, in suspension. The beauty of nanofluids is that they will reduce or eliminate the problems associated with larger particles. Their extremely fine size permits them to flow without clogging or abrading pumps.  They are less prone to precipitation, and that can be mitigated or eliminated with appropriate treatments and dispersion techniques.

The company has existing manufacturing capability in various nanomaterials, for example, copper (200nm, 100,000 kg/yr), silver (10 nm), pus other metals, oxides, ceramics, and carbon nanotubes. Within its network of partnerships and alliances with universities, government laboratories and other companies, The company has access to heat transfer measurement and modelling expertise. Furthermore, The company has an established, proprietary technique for forming copper nanofluids in chemical systems very similar to those used in automotive coolants.

Nanocoatings to Prevent Fouling and Corrosion

In the past, diamond-like coatings were recognized to have the optimal surface properties that prevent mineral scale deposition. However, they tend to delaminate from the metal substrate, the pipe.

In comparison with past generation diamond-like coatings, the companies product has greatly enhanced adhesion properties while retaining the desired surface properties. The product is a nanocomposite of quasi-amorphous graphite-like and diamond-like carbon, typically alloyed with oxygen, hydrogen, and silicon.

The silicon and oxygen form a SiOx network easily forms chemical bonds with virtually any substrate without requiring a special interlayer. So in addition to preventing build-up of deposits, the product’s excellent adhesion properties will prevent under-deposit corrosion.