Paper No 376 – Flow Boiling Heat Transfer Performance of R448A inside Multiports Mini-Channel tubes with different geometry – 14th IEA Heat Pump Conference, Chicago, USA
R448A, a zeotropic blend with GWP of 1390, is being proposed as an alternative refrigerant working in airconditioning and heat pump systems. Despite being suitable as drop-in refrigerants, some redesigning of R448A systems was recommended for achieving maximum efficiency. In the work, the heat transfer coefficient of R448A inside multiple multiport mini-channel tube with different geometries were experimentally investigated. The experimental range of mass flux is from 100 to 500 kg/m2 s, heat flux from 3 to 15 kW/m2 at a fixed saturated temperature of 6oC, in 3 multiport tubes with varying hydraulic diameter, number of ports and aspect ratio. The influence of mass flux, heat flux, and vapor quality are examined, as well as the effect of channel geometry on the heat transfer performance. Finally, a correlation including the channel geometrical effect is proposed for the prediction of R448A heat transfer coefficient.