Experimental Investigation On Condensation Heat Transfer Enhancement Of R407C Refrigerant In Helical Baffle Condensers With Enhancement Tubes

Since 1985 the English Antarctic expedition discovered the ozone hole, people pay much more attention on it. As one of major crime culprits which manufactured the ozone hole, R22 Freon refrigerant is forbidding to use in refrigeration Industry, gradually. R407 C is an environmentally friendly refrigerant. The ODP of R407 C is zero which mean it has no damaging effects on the Ozone layer. Thus, R407 C is a powerful alternative for Freon refrigerant R22. So research on the condensation heat transfer performance of R407 C is meaningful. In addition, the heat transfer enhancement technologies should be used in heat exchangers in order to saving the energy. Furthermore, Using advanced enhanced tubes and helical baffles are the effective ways to improve the heat transfer performance of refrigerant and reduce the cost of heat exchangers.In this research, the condensation heat transfer performance of R407 C in different condensers included helical baffle condenser with smooth tubes(HBS), helical baffle condenser with low fin tubes(HBF) and helical baffle condenser petal shaped fin tubes(HBP) were investigated at saturation temperature of 35℃ and 39 ℃. A semi-experimental, semi-theoretical computational formula was carried out based on the experimental result. Also, the heat transfer performance of different condensers and investigated the heat transfer enhancement between low fin tube and petal shape fin tube compared.According to the experimental result, the heat transfer performance of R407 C in heat exchangers has been improved by using the enhancement tubes. And the rank of improvement is HBP>HBF>HBS. Under the same wall sub-cooling temperature, the enhanced magnification of HBP is 1.91~2.60; HBF is 1.04~1.34. So the HBP has much better heat transfer performance than HBF.Besides, the ratio of outside-tube heat transfer resistance of three condensers are :70%~72% for HBS; 69%~70% for HBF; 59%~62% for HBP which indicated that the control heat transfer resistance of R407 C condensation process is outside the tube. Meanwhile, the outside-tube heat transfer resistance.has great decrease by using the petal sharp fin tube...