Nanofluids which consist of nanoparticles added to conventional fluids (or base fluids) are considered as promising heat transfer fluids. Compared to metal, metal oxide nanoparticles and carbon nanotubes, graphene with its extremely high intrinsic thermal conductivity became the best candidate to design nanofluids. Such nanofluids have the potential to be highly-efficient heat transfer fluid by reducing loss of heat and increasing cooling rates. Over the last ten years, graphene-based nanofluids have shown significant thermal conductivity enhancements, however due to the numerous and interlinked parameters to consider, optimisation of their efficiency is still challenging. The present review article analyses and discusses the reported thermal conductivity in term of performance with respect to the amount of the used graphene to develop the prepared nanofluids. The enhancement of thermal conductivity must meet the minimal graphene amount due to its production cost and because graphene nanoparticles induces high viscosity in the nanofluid leading to higher energy consumption for the heat transfer systems. Unprecedented in the literature, this work proposes a simple approach to quantitatively compare the enhancement of the thermal conductivity of the nanofluids. The thermal conductivity performance parameter introduced could be applied to all nanofluid families and may become a reference tool in the nanofluid community. Such tool will help to determine the optimal preparation conditions without compromising the superior thermal performances.

由添加到常规流体（或基础流体）中的纳米粒子组成的纳米流体被认为是有前途的传热流体。与金属、金属氧化物纳米粒子和碳纳米管相比，石墨烯具有极高的固有热导率，成为设计纳米流体的最佳候选材料。通过减少热量损失和提高冷却速度，这种纳米流体有可能成为高效的传热流体。在过去的十年中，基于石墨烯的纳米流体已经显示出显着的导热性增强，但是由于需要考虑众多且相互关联的参数，其效率的优化仍然具有挑战性。本综述文章分析和讨论了所报告的导热率，其性能与用于开发制备的纳米流体的石墨烯量有关。由于其生产成本以及石墨烯纳米粒子在纳米流体中引起高粘度导致传热系统的更高能耗，因此导热率的增强必须满足最小石墨烯量。这项工作在文献中史无前例，提出了一种简单的方法来定量比较纳米流体热导率的增强。引入的导热性能参数可应用于所有纳米流体家族，并可能成为纳米流体界的参考工具。