Evaluating the potential of vortex-enhanced evaporator performance for refrigeration applications

In many refrigeration systems, overall evaporator performance is limited by the heat transfer and pressure-drop behavior of the air side. The air side limits performance because the heat transfer coefficients are inherently lower for single-phase gas flow than for the two-phase refrigerant flow. Therefore, it is important to identify air-side performance enhancements suitable for the low-Reynolds-number frosting conditions found in these applications. In this paper the results of a preliminary assessment of vortex-induced air-side heat transfer enhancement for refrigeration applications are reported. The results indicate that longitudinal vortices may significantly improve air-side thermal performance, leading to smaller heat exchangers for a fixed duty or to better thermal performance for a fixed heat exchanger envelope. Further research is recommended to evaluate the to-scale performance of vortex generators under frosting conditions.