An improved correlation for condensation heat transfer of R-134a in horizontal tubes

An experimental investigation on flow condensation heat transfer characteristics of R-134a and R-12 in a horizontal smooth tube was performed. The refrigerant in the test-tube was cooled by water flowing through an annulus surrounding the tube. The total test-tube is 13.0 m in length with an inner diameter of 11.0 mm. Condensation tests were performed for a refrigerant temperature range of 27 degrees C-35 degrees C with inlet and exit qualities of 1.0 and 0.0, respectively. The mass flux was varied from 250 to 500 kg/(m(2).s). Local average heat transfer coefficients. for different refrigerant flow rates were experimental determined for the ten sub-sections separately A new correlation based on two existing correlations was proposed, which can predict the present data with smaller deviations than that of the two original correlations.