유로변경에 따른 소형 냉동시스템의 성능특성에 관한 실험적 연구 = An experimental study on the performance characteristics of a small refrigeration system with a variation of refrigerant path

다국어 초록 (Multilingual Abstract)

The object of this study is to investigate the performance characteristics of a small refrigeration system with multi evaporator cycle and to improve energy efficiency by optimization of refrigeration cycle. The multi evaporator cycle can be categorized into a single-circuit multi cycle, a bypass two-circuit multi cycle and a parallel two-circuit multi cycle. In this study, the performance of a refrigeration system, which consists of a compressor, condenser, two capillary tubes, and two evaporators, was measured in a bench type refrigeration cycle. Each refrigeration cycle was tested by varying the refrigerant charge amount, secondary fluid mass flow rate and temperature. Besides, the performance of the parallel two-circuit multi cycle was measured by varying capillary tube inner diameter. Based on the experimental data, the optimum refrigerant charge was 48 g and the COP at the optimum secondary fluid mass flow rate was 1.53 for the single circuit multi cycle. For freezer(F) only-mode, both the single circuit multi cycle and the bypass two-circuit multi cycle were operated at overcharge condition, so resulting in an increase of secondary fluid mass flow rate. Then the COP of the single circuit multi cycle was 1.22 and the COP of the bypass two-circuit multi cycle was 1.35. The COP increased by 10.7% by applying the bypass two-circuit multi cycle. The parallel two-circuit multi cycle was optimized at the refrigerant charge of 34 g and capillary tube inner diameter of 1.2 mm for refrigerator(R) only-mode, and 36 g for F only-mode. The COPs of the parallel two-circuit multi cycle were 1.79 for R only-mode and 1.70 for F only-mode, respectively. According to the results, the parallel two-circuit multi cycle showed better performance than the other cycles. For refrigerator, the COP of the parallel two-circuit was 17.1% higher than the bypass two-circuit multi cycle, so working hours will be decreased to satisfy the cooling load. For F-only mode, the COP of the parallel two-circuit multi cycle was 25.9% higher than the bypass two-circuit multi cycle due to the difference of refrigerant charge amount.

목차 (Table of Contents)

• Abstract ⅰ
• Contents ⅲ
• List of Figures ⅵ
• List of Tables ⅸ
• Nomenclature ⅹ
• 제 1 장 서론 1
• 1.1 연구배경 1
• 1.2 연구동향 3
• 1.3 연구목적 및 내용 7
• 제 2 장 실험장치 구성 및 실험방법 10
• 2.1 소형 멀티 냉동시스템 10
• 2.2 실험장치 구성 16
• 2.3 계측장치 21
• 2.4 실험 조건 29
• 2.5 실험 방법 10
• 2.6 성능 계산 35
• 제 3 장 실험결과 및 고찰 36
• 3.1 단일유로 멀티사이클의 성능특성 고찰 37
• 3.1.1 냉매 충전량 변경에 따른 성능특성 37
• 3.1.2 냉장실 고내온도 변경에 따른 성능특성 41
• 3.1.3 냉동실 풍량 변경에 따른 성능특성 45
• 3.1.4 냉장실 팬 정지운전 시 냉동실 풍량 변경에 따른 성능특성 47
• 3.2 바이패스유로 멀티사이클의 성능특성 고찰 51
• 3.2.1 냉매 충전량 변경에 따른 성능특성 51
• 3.2.2 냉동실 풍량 변경에 따른 성능특성 56
• 3.3 병렬유로 멀티사이클의 성능특성 고찰 58
• 3.3.1 냉매 충전량 변경에 따른 성능특성 58
• 3.3.2 냉장실 풍량 변경에 따른 성능특성 66
• 3.3.3 냉동실 풍량 변경에 따른 성능특성 69
• 3.4 유로변경에 따른 멀티사이클의 성능특성 비교 71
• 3.4.1 냉장실 부하 충족 71
• 3.4.2 냉동실 부하 충족 74
• 제 4 장 결론 77
• 4.1 단일유로 멀티사이클의 성능특성 77
• 4.2 바이패스유로 멀티사이클의 성능특성 78
• 4.3 병렬유로 멀티사이클의 성능특성 79
• 4.4 유로변경에 따른 성능특성 비교 80
• 참고문헌 81