抄録
This paper deals with an experimental study on the flow boiling and condensation heat transfer of low-GWP refrigerant R1234ze(E) inside a horizontal micro-fin tube. The test section is a 2.2 m long double-tube type heat exchanger, where the refrigerant flows in the inner tube and heat sink or heat source water flows in the annulus surrounding the inner tube. The annulus is divided into four subsections, each of which is 454 mm long. A tested micro-fin tube used as inner tube is made of copper and its mean inside diameter is 5.21mm. The measured axial distribution of refrigerant, tube wall and water temperatures, heat flux, heat transfer coefficient, vapor quality and pressure drop are graphically shown. Effects of mass velocity on local heat transfer and pressure drop characteristics are also shown. Furthermore, the measured local heat transfer coefficient and pressure drop are compared with several previous correlations to confirm whether these correlations are available to use the heat exchanger design for air-conditioning system.
