HORIZONTAL FLOW BOILING OF R22 AND R407C IN A 9.52MM MICRO-FIN TUBE

The two-phase heat transfer coefficient and pressure drop characterist ics of refrigerant R22 and R407C (a mixture of R32/R125/R134a, 23%/25% /52%) in a micro-fin tube with nominal diameter 9.52 mm were presented in this study. Experimental data were taken at an evaporation pressur e of 600 kPa. The mass flux was between 100 and 300 kg/m(2) . s and th e heat fluxes were between 6 and 14 kW/m(2). Experimental data were pr esented in the form of length-averaged heat transfer coefficients and frictional pressure gradients. The effect of heat flux and mass flux o n the heat transfer coefficients were also reported in the present inv estigation. It is found that the heat transfer coefficients for R407C are considerably lower than R22 (50 similar to 80% less), and the pres sure drop of R407C is 30 similar to 50% lower as compared to R22. Copy right (C) 1996 Elsevier Science Ltd