The R1224yd(Z) is a new HFOs’ molecule with GWP<1 and nearly zero ODP. It has a normal boiling temperature around 14°C, which makes it suitable as blowing agent as well as refrigerant for electronics cooling applications and for high temperature heat pumps.

This paper presents the R1224yd(Z) flow boiling heat transfer and pressure drop measurements inside a mini microfin tube with internal diameter at the fin tip of 4.2 mm. The experimental measurements were carried out at constant mean saturation temperature of 30 °C, by varying the refrigerant mass velocity between 100 and 200 kg m^-2 s^-1, the vapour quality from 0.2 to 0.95, at three different heat fluxes: 15, 30, and 60kW m^-2. The experimental results are presented in terms of two-phase heat transfer coefficient, onset dryout vapour quality, and frictional pressure drop.

This new HFO fluid shows promising heat transfer capabilities, which makes it a possible viable substitute of high-GWP, low-pressure refrigerants.