HFO1234ze(E) CONDENSATION INSIDE ABRAZED PLATE HEAT EXCHANGER

摘要

This paper presents heat transfer coefficients and pressure drops measured during condensation of HFO1234ze(E), a low Global Warming Potential (GWP) refrigerant, inside a brazed plate heat exchangerfor various values of saturation temperature, refrigerant mass flux and vapour super-heating. The heattransfer coefficients show weak sensitivity to saturation temperature and great sensitivity to refrigerant massflux and vapour super-heating. At low refrigerant mass fluxes (< 20 kg m~(-2)s~(-1)) the heat transfer coefficientsare independent of mass flux and condensation is gravity-dominated. For higher refrigerant mass fluxes (>20kg m-2s-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% to 35% enhancementfor a doubling of the refrigerant mass flux. The condensation heat transfer coefficients of super-heatedvapour are from 8% to 11% higher than those of saturated vapour. HFO1234ze(E) exhibits lower (4% to6%) heat transfer coefficients and higher (10% to 20%) frictional pressure drops than those of HFC134a under the same operating conditions.