무착상 조건에서 R404A, R134a, R744를 적용한 냉동탑차용 냉장시스템의 성능변화 비교
Comparison of Cooling Performance in a R404A, R134a, and R744 Refrigeration Truck Under Non-Frost Condition
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An automotive air-conditioning system and refrigeration truck are normally used refrigeration R134a and R404A, respectively. In this study, the theoretical study on the performance of R744, R134a, and R404A refrigeration system for the refrigeration truck was carried out for varied operating conditions. As a result, the refrigeration capacity of all system was designed with 2.5 kW at the standard conditions, and the COP of R134a system was the highest. The performance of all systems with the outdoor temperature rapidly decreased. In addition, when outdoor air velocity varied from 1 to 2 m/s, the performance improvement was noticeable, but it didn't increase anymore when outdoor air velocity exceeded 4 m/s due to a decrease in the effectiveness of the heat exchanger. As compressor RPM increased, the performance reduced most for R134a system. The R134a system showed the smallest change in performance with changing in operating conditions.
Abstract
An automotive air-conditioning system and refrigeration truck are normally used refrigeration R134a and R404A, respectively. In this study, the theoretical study on the performance of R744, R134a, and R404A refrigeration system for the refrigeration truck was carried out for varied operating conditions. As a result, the refrigeration capacity of all system was designed with 2.5 kW at the standard conditions, and the COP of R134a system was the highest. The performance of all systems with the outdoor temperature rapidly decreased. In addition, when outdoor air velocity varied from 1 to 2 m/s, the performance improvement was noticeable, but it didn't increase anymore when outdoor air velocity exceeded 4 m/s due to a decrease in the effectiveness of the heat exchanger. As compressor RPM increased, the performance reduced most for R134a system. The R134a system showed the smallest change in performance with changing in operating conditions.
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