Characteristics of Condensation Heat Transfer and Pressure Drop using HC Refrigerants flowing inside a Horizontal Tube

摘要

Experimental results for heat transfer characteristic of R-290 (Propane), R-600a (Iso-butane) and R-1270 (Propylene) as an environment friendly refrigerant and R-22 during condensing and evaporating inside horizontal double pipe heat exchangers are presented. The test sections which have the tube diameter of 12.70mm, 9.52mm, and 6.35mm are used for this investigation. The main results were summarized as follows: The local condensing heat transfer coefficients of hydrocarbon refrigerants were higher than that of R-22. The average condensing heat transfer coefficient increased with the increase of the mass flux. It showed the higher values in hydrocarbon refrigerants than R-22. The experimental heat transfer coefficients agreed with the correlations of Shah, Travis, Cavallini-Zecchin and Haraguchi's to within ±30%. The local condensing pressure drops (inside the tube) of hydrocarbon refrigerants were higher than R-22. And, HC refrigerants suffer from the problem of higher average pressure drops by at least 50% than R-22. This results form the study can be used in the case of designing heat transfer exchangers using hydrocarbons as the refrigerant for the air-conditioning systems.