CONDENSATION HEAT TRANSFER AND PRESSURE DROP OF R410A INSIDE A HORIZONTAL SMOOTH SMALL-DIAMETER TUBE

In this paper, we present an experimental study of condensation heat transfer and pressure drop using a horizontal smooth small-diameter tube with an outside diameter of 4.00 mm. The experimental apparatus is a vapor-compression heat pump system, which consists of a compressor, a pre-condenser, test sections, a rear-condenser, a receiver, an electronic expansion valve, an evaporator, and heat-source systems. In the experiments, R410A was used as the refrigerant; the ranges of refrigerant mass flow velocity varied from around 215 to 1290 (kg/m(2)s), and the condensation saturated temperatures were maintained at 35 degrees C and 40 degrees C. From the experimental results, we compared the experimental local condensation heat-transfer coefficients and pressure drops with the empirical correlation proposed by the authors and others. The experimental values of the local condensation heat-transfer coefficients agreed within +/- 35% with the empirical correlation proposed by the authors. The experimental values and the estimation formula for pressure drop agreed within +/- 20% in the range of 850 kg/m(2)s or more by the authors.