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CHAPTER 11. Refrigeration Cycles. The objective of a refrigerator is to remove heat (Q L ) from the cold medium; the objective of a heat pump is to supply heat (Q H ) to a warm medium. (대기, 지열, 바다). 10-1. Schematic and T- s diagram for the ideal vapor-compression refrigeration cycle.
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CHAPTER 11 Refrigeration Cycles
The objective of a refrigerator is to remove heat (QL) from the cold medium; the objective of a heat pump is to supply heat (QH) to a warm medium. (대기, 지열, 바다) 10-1
Schematic and T-s diagram for the ideal vapor-compression refrigeration cycle. 10-3
냉매 탄화수소계( 프로판, 에탄, 에틸렌…), CO2, air… Ammonia- low cost, high COP, toxic – 대형 상업용 냉동기 Chlorofluorocarbon 계열( CFC- R-11, R-12, R-22, R115, R502(R115+R22): 프레온 ) – 오존층 파괴 R134a- Cl 없음. 1 냉동톤 (tons of refrigeration) – 24시간에 0oC인 물 1 ton 을 0oC 의 얼음으로 만드는 냉동장치의 능력 증기압축 냉동기 : 구조간단, 저가, 믿을만하고 고장이 거의 없다.
The P-h diagram of an ideal vapor-compression refrigeration cycle. 10-5
Schematic and T-s diagram for the actual vapor-compression refrigeration cycle. 8-1 사이 거리가 통상 길다 압축기에서 외부로의 열손실 10-6
FIGURE 10-16Simple gas refrigeration cycle. 역Brayton cycle : 공기 압축 냉동기 비행기 냉동 10-12
흡수식 냉동기 냉매(암모니아)-운반물질(물) Water- lithium bromide Ammonia absorption refrigeration cycle. Qgen >>Wpump 암모니아 흡수반응 : 발열 반응 저온이어야 용이함 10-16
When one of the junctions of two dissimilar metals is heated, a current I flows through the closed circuit. Seebeck 효과 열전대 발전 thermoelectric 10-18
When a current is passed through the junction of two dissimilar materials, the junction is cooled. Peltier effect low COP 10-22