Experimental study on boiling heat transfer and flow regime of R454C in parallel staggered-finned minichannels.

To mitigate environmental concerns related to global warming, a transition to refrigerant mixtures with lower global warming potential is crucial. However, the heat transfer performance of these mixtures is inferior to that of pure refrigerants. To enhance heat transfer of mixtures, channel structures must be optimized to reduce mass diffusion resistance. In this study, the boiling heat transfer and flow regime of HFC/HFO refrigerant R454C in parallel staggered-finned minichannels (SFMs) was experimentally investigated, and the results were compared with those of continuous minichannels (CMs). Staggered fins in the SFM led to enhanced heat transfer coefficients by up to 30% at G ≥ 100 kgm-2s-1 due to the enhancement of flow agitation. The frictional pressure drop in the SFM exceeded that in the CM owing to increased flow resistance.