In-tube evaporation of R-22 and three of its alternatives in a 15.88 mm internally enhanced tube

In-tube evaporation heat transfer and pressure drop comparisons were perfor med with R-22 and three of its HFC alternatives, R-134a, R-407C, and R-507, with a commercially available 15.88 mm internally enhanced tube 75 interna l ridges with 0.305 mm (0.012") ridge height and a helix angle of 23 degree s (Turbo-DX(R)-75 ridge as manufactured by Wolverine Tube, Inc,); The exper iments were performed over an appropriate mass Aux range - 25-275 kg/s-m(2) (R-407C was tested from 25-170 kg/s-m(2)) - to ensure that the data were a pplicable for many uses. The R-22 evaporation data for this tube from Thors and Bogart ( 1994) is reprinted here for comparison purposes and the balan ce of the data presented are new. The data indicate that R-22 has the highe st evaporation coefficient of all of the refrigerants. The results also sho w that R-507 has a considerably lower pressure drop than the other three re frigerants.