Condensation of the low GWP refrigerant HFO1234ze(E) inside a Brazed Plate Heat Exchanger

This paper presents heat transfer coefficients and pressure drops measured during condensation of the low GWP refrigerant HFO1234ze(E) inside a BPHE. The condensation temperature ranges between 24.8 and 40.2 °C, the refrigerant mass flux from 10.7 to 39.9 kg m−2 s−1 and the heat flux from 5.3 to 26 kW m−2. The heat transfer coefficients show weak sensitivity to saturation temperature and great sensitivity to refrigerant mass flux and vapour super-heating. At low refrigerant mass fluxes (<20 kg m−2 s−1) the heat transfer coefficients are independent of mass flux and condensation is gravity-dominated. For higher refrigerant mass fluxes (>20 kg m−2 s−1) the heat transfer coefficients depend on mass flux and forced convection condensation occurs. In the forced convection condensation region the heat transfer coefficients show a 32%–35% enhancement for a doubling of the refrigerant mass flux. The condensation heat transfer coefficients of super-heated vapour are from 8% to 11% higher than those of saturated vapour. HFO1234ze(E) exhibits lower (4%–6%) heat transfer coefficients and higher (10%) frictional pressure drops than those of HFC134a.