The heat transfer fluids with high efficiency of heat transfer is more favourable for the heat exchange systems. However, the low thermal conductivities of conventional fluids becomes a limiting factor when it comes to designing a compact heat exchanger. One of the methods to increase this efficiency is by suspending a small amount of nanoparticles of high thermal conductivity into the conventional fluids. It is subsequently called “nanofluid”.

The work done by Dr Sebastian, Dr Ting and Dr Vigolo reported in this paper performs a direct comparison between two types of carbon-based nanofluids under the same operating conditions and the same heat exchanger. Specifically, they are studying the performance of water-based graphene nanoplatelet (or GnP)- and multi-walled carbon nanotube (or MWCNT)-nanofluids.

Based on their study, the thermal performance of GnP-nanofluids has better heat transfer coefficient (HTC) than that of MWCNT-nanofluids. They attributed the higher performance of GnP to its ability to emit a greater amount of heat from the nanofluid. Finally, they also pointed out the importance of an optimised nanofluid concentration as well as appropriate size and shape of carbon nanoparticles for a better thermal performance of nanofluids.