Evaporation heat transfer characteristics of R-410A in 7 and 9.52 mm smooth/micro-fin tubes

In-tube evaporation heat transfer characteristics of R-410A were experimentally investigated and analyzed as a function of evaporating temperature, mass flux, heat flux, and tube geometry. Evaporation heat transfer coefficients and pressure drops were measured for 3.0 m long smooth and micro-fin tubes with outer diameters of 9.52 and 7.0 mm, respectively. The test matrix in the present study included measurements for evaporation over a refrigerant mass flux range of 70–211 kg/m2s, a heat flux range of 5–15 kW/m2 and an evaporating temperature range of −15 to 5. The objective of this study is to evaluate the heat transfer enhancement of the micro-fin tube with R-410A as a function of mass flux, heat flux, evaporating temperature and tube diameter.