Min-Ju Jeon is currently a lecturer at Pukyong National University. Here is a brief introduction to what has been studied so far. 1. Research on refrigeration systems such as heat pump systems, cascade refrigeration systems, and indirect refrigeration systems to which a R744 refrigerant is applied. 2. R744 evaporative heat transfer. 3. Research related to COP and exergy analysis and mass flow prediction for system optimization.  An introduction to the study results is given below. 1. Heat and mass transfer, applied sciences-basel, etc. Eight SCI-level papers and nineteen non-SCI-level papers were submitted, and forty-seven papers were presented at an academic conference. 2. Successfully completed 27 different projects.