Abstract: “Analytical and experimental studies on singlephase natural circulation loops (thermosyphons - NCL ) have been performed in the past years by several authors,. However the problem of the stability of the loops, that is of interest in many industrial applications, cannot be considered solved. The present paper is focused on the experimental aspects that could be interesting in the study of these thermal systems. In particular, the following NCLs aspects will be discussed: applications, models, thermo-hydraulic behaviour, and influence of loop size. Finally a broad reference list is cited”

Keywords: natural circulation, single-phase, instabilities, nanofluids)