| Title |
Study on the Performance of New Two-Stage Expansion Auto-Cascade Refrigeration System with CO2-R134a Mixed Refrigerants |
| Authors |
Il Young Jung ; Kyung Rok Mun ; Sang Kook Yun |
| DOI |
http://dx.doi.org/10.6110/KJACR.2018.30.11.526 |
| Keywords |
오토 다단 냉동기 ; 2단 팽창 ; 성능계수 ; CO2-R134a 혼합냉매 Auto-cascade refrigerator ; Two-stage expansion ; Coefficient of performance ; CO2-R134A refrigerant mixture |
| Abstract |
Air-cooled CO2 refrigerators have several disadvantages, which have much difficulties to manufacture the components due to super-critical pressure over 130 bar, and to make efficient evaporation using ambient air in cold winter because of higher evaporation temperature. This research aims to overcome these disadvantages and to improve the energy efficiency by introducing a new lower-pressure two-stage expansion process in auto-cascade heat pump system. The CO2-R134a zeotropic refrigerants in two-stage expansion in the effective flow configuration process of new auto-cascade refrigerator is considered. Results indicate that the new two-stage expansion system shows significant performance improvements as about 180% higher when high pressure of 50 bar, intermediate expansion pressure of 30 bar, and final low pressure of 7 bar are applied. It operates at a much lower evaporation temperature of -10℃ or below than original one-stage expansion system. |