Testing shows Green Critical Minerals’ VHD graphite could help data centres chill out

Testing has shown that Green Critical Mineral’s VHD graphite has excellent thermal diffusivity properties that make it well suited for cooling AI data centres.

GCM’s VHD Graphite have superior thermal diffusivity and are ideally suited for cooling data centres. Pic: Getty Images

• Testing proves that VHD graphite has 3x better thermal diffusivity than aluminium and graphite and 2.6x better than copper

• GCM’s material also has a 25x directional advantage, allowing for more precise heat dissipation

• Company is now designing heat sinks for use in AI data centres

Special Report: Green Critical Minerals has enhanced the commercial value of its very high density (VHD) graphite blocks after testing for thermal efficiency returned breakthrough results to industry-leading materials available in the market.

The testing, which had never been carried out before on VHD graphite, achieved a peak thermal diffusivity result of 288m2/s – significantly better than copper, aluminium and conventional graphite for mass market thermal management materials.

Adding further interest, the testing found that at 14.3% weight efficiency, heat diffuses through VHD graphite about 12 times faster per unit of weight than copper.

This is further supported by a 25x directional advantage that allows for more precise heat dissipation.

Green Critical Minerals (ASX:GCM) adds the material is the most effective mass high-tech cooling material as it has 3x higher thermal diffusivity than aluminium and standard graphite and 2.6x higher than copper.

To top all this off, the high-density and anisotropy results match lab-scale performance – demonstrating successful replication at the pilot-plant scale.

AI data centre cooling

While thermal conductivity indicates how easily one atom or molecule of a material accepts or gives away heat, thermal diffusivity measures how quickly heat spreads through an object and plays a critical role in thermal management, as it determines how fast heat is transferred through a material so it can be dissipated to the surrounding environment.

In other words, materials with higher thermal diffusivity – such as VHD graphite – have the potential to be more effective in thermal management situations, as they have a potentially greater capacity to reduce hotspots, reduce radiant heat and move the heat faster to the desired location.

The ultra-fast heat spreading, lightweight structure, and targeted cooling properties of VHD graphite makes it ideal for high-density server racks, high-performance computing, and AI processor infrastructure.

“These latest results mark a significant milestone in proving VHD graphite’s ability to revolutionise high-performance thermal management,” managing director Clinton Booth said.

“VHD graphite has not previously been tested for thermal diffusivity and these results represent a new and advanced property of VHD graphite and importantly, confirm its thermal performance superiority for applications such as heat sinks.

“GCM engaged the University of New South Wales to use the latest and most precise technology to determine the thermal diffusivity of VHD graphite.

“The confirmation of exceptional thermal diffusivity, in conjunction with anisotropy and high-density repeatability, demonstrates its potential to outperform copper and aluminium in AI cooling, semiconductor applications and next-generation heat sinks.

“With the demand for advanced thermal solutions increasing, VHD graphite is emerging as the logical successor to traditional materials and a disruptor to the heat sink market.

“These results provide Green Critical with a high level of confidence in delivering on the commercial scalability of the VHD technology and we will now move straight into the heat sink design phase.

“We have made excellent progress toward our primary objective of commencing commercialisation by the end of 2025 and we remain focused on continuing to execute on our strategy at a rapid pace and unlock the significant potential of our VHD technology”.

Industry-leading performance

GCM acquired the ground-breaking technology to convert graphite into very high-density graphite blocks at the end of October 2024.

These blocks have amongst the highest thermal conductivity ever recorded for any bulk material – up to 617 W/m·K along the grain – and the lowest electrical resistivity (of 1.2 µΩ·m) ever measured for any bulk graphite product.

Notable applications include materials for the defence and nuclear industries, thermal energy storage systems, high-performance electronics, battery electrodes, heat sinks and aerospace.

What’s even more remarkable is that the VHD blocks can be produced in just 24-36 hours at around half the temperature (1500C v 2900C) of the primary synthetic graphite process.

Data received to date on VHD graphite’s anisotropy, density and thermal diffusivity properties have allowed GCM to progress to the heat sink design phase.

Designing heat sinks will also allow the company to progress computational modelling to predict their behaviour in an operating environment.

This article was developed in collaboration with Green Critical Minerals, a Stockhead advertiser at the time of publishing.

This article does not constitute financial product advice. You should consider obtaining independent advice before making any financial decisions.

Originally published as Testing shows Green Critical Minerals’ VHD graphite could help data centres chill out