Nanofluids: Critical issues, economics and sustainability perspectives

According to the Scopus database, every year several hundreds of new research papers are published in the field of nanofluids. This area is attracting growing attention because of the significant improvement in the heat transfer and energy efficiency of the systems working with nanofluids. However, as results from numerous scientific studies conducted by independent laboratories, there are several fundamental problems related to the unambiguous determination of their physical properties, their production, and economic use. Although most studies often focus on one issue or cover one kind of research or mathematical correlation, this review paper provides insights into many problems during nanofluids research by proposing solving possibilities, which is the strength of our work. The paper discusses the case of nanofluids quality, and morphology, thermal conductivity enhancement and the discrepancies in mathematical modelling, errors in dimensional and similarity analysis, nanofluid erosion, safety guidelines, and toxicology tips. Moreover, the sustainability and economics of nanofluids usage are also being discussed.(c) 2023 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.