NANOFLUIDS: The Institution of Engineering & Technology

Liquids incorporating nanoparticles could be more effective than standard coolants in applications from locomotives to data centres, electric vehicles to wind turbines. A new European research project aims to develop and produce suitable nanofluids and demonstrate their technical and commercial viability. By Lorna Sharpe

Nanohex is a three year project bringing together 12 partners from academia and industry, ranging from SMEs to major companies such as Siemens and led by Northumberland-based thermal management specialist Thermacore. It is funded by the European Commission, with additional investment by the partners.

Nanofluids (carrier liquids into which particles smaller than 100nm have been dispersed) have shown considerably higher thermal conductivities than conventional cooling fluids. This project will develop new liquid coolants using specifically engineered nanoparticles.

The Centre for Process Innovation is responsible for managing the project, which CPI commercialisation manager Dr Andrew Round describes as "no mean feat," with 12 participants across the whole supply chain. Different groups will work on fundamental materials physics, design of nanoparticles and fluids, characterisation of their behaviour - including safety and environmental impacts - and practical applications.

"At the end of the project we will have two commercially viable field demonstrators," said Round, "one for a data centre and one to cool the power electronics on a train".

In data centres, as components get smaller and more powerful they generate more heat, to the point where cooling capacity is a major limitation on power density. Enhanced cooling would allow the same processing power in fewer cabinets, reducing the space required and cutting costs.

The same issue applies in railway applications, Round explained, which is why Siemens - a leading train manufacturer - is involved. The electronic switches known as IGBT modules are becoming more sophisticated and consume more power, so they get hot, and heat shortens the life of electronic devices. Better cooling can improve reliability and cut maintenance and through-life costs, as well as enabling increased power from existing engine designs.

IGBT modules are found not only in trains but also in wind turbines, power stations and electric vehicles. "When we wrote the project we hadn't looked at automotive," said Round, "but we're seeing the same issues there, especially with electric vehicles." All cars get hot while they are running, he pointed out, but electric ones also get hot when they are being charged, so the wear and tear on components can be much higher.

The large truck market also stands to benefit, particularly through the trend towards more aerodynamic designs. At present, the front shaping is constrained by the need for a large radiator. With nanofluid coolants, Round predicts, the heat would still be taken up but it could be dissipated in a different way. "It would be possible to engineer out the radiator and put it elsewhere in the vehicle".

In the end, a manufacturer's choice of coolant will come down to a trade-off. "Nanofluids will never be as cheap as water-glycol mixes, but early results in the literature show big performance benefits," Round concluded.