Supercritical CO2 as heat transfer fluid: A review

This paper presents a comprehensive review of all correlations and experimental studies available in the literature to determine the heat transfer coefficient of supercritical CO2 flowing in heat exchangers. The different applications in which it is used are also reviewed and discussed. The correlations obtained from extensive experimental measurements are presented for different geometries (horizontal, vertical and inclined tubes, closed-loop circular pipes, and mini-channels) and dimensions. The review shows that there is a lack of a unique universal correlation for each geometry, suggesting the need for more work in this area.The work partially funded by the Spanish government (ENE2015-64117-C5-1-R (MINECO/FEDER) and ENE2015-64117-C5-3-R (MINECO/FEDER)). The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2014 SGR 123). This project has received funding from the European Commission Seventh Framework Programme (FP/2007-2013) under Grant agreement N°PIRSES-GA-2013-610692 (INNOSTORAGE) and from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 657466 (INPATH-TES), and the funds received by the Royal Society of New Zealand. Alvaro de Gracia would like to thank Ministerio de Economia y Competitividad de España for Grant Juan de la Cierva, FJCI-2014-19940