The　flow　condensation　of　R1234ze(E),　R450A,　and　R515B　was　conducted　in　a　6.14　mm　inner　diameter　micro-fin　tube.　The　fin　height　is　0.18　mm　and　the　fin　number　is　50.　The　helix　angle　is　18°　and　the　area　enhancement　factor　is　1.63.　During　the　experimental　tests,　the　saturation　temperature　is　30　and　40　°C.　The　mass　fluxes　range　from　50　to　400　kg　m-2　s-1.　The　vapor　qualities　are　between　0.1　and　0.96.　The　heat　transfer　coefficients　and　frictional　pressure　gradients　of　the　three　refrigerants　were　compared　with　each　other.　The　experimental　heat　transfer　coefficient　increases　with　vapor　quality　and　mass　velocity,　except　at　high　vapor　quality,　where　a　higher　mass　velocity　does　not　imply　a　higher　heat　transfer　coefficient,　probably　due　to　the　liquid　film　thickness　distribution.　Generally　speaking,　R450A　presents　slightly　higher　heat　transfer　coefficients　at　high　mass　fluxes　and　smaller　pressure　gradients,　whereas　R515B　shows　lower　heat　transfer　coefficients　and　pressure　drops　very　close　to　those　of　R1234ze(E).　Moreover,　some　models　of　the　heat　transfer　coefficient　and　pressure　gradient　specifically　developed　for　micro-fin　tubes　were　chosen　to　explore　their　feasibility　for　the　new　refrigerants　and　tube.　Cavallini　et　al.’s　model　shows　the　best　agreement　for　the　heat　transfer　coefficient,　and　Diani　et　al.’s　model　shows　the　best　agreement　for　the　frictional　pressure　gradient.　©　2022　Elsevier　Ltd