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CHAPTER

10

Refrigeration Cycles

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

10-1

FIGURE 10-1The 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.

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.FIGURE 10-2Schematic of a Carnot refrigerator and T-s diagram of the reversed Carnot cycle.

10-2

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

10-3

FIGURE 10-3Schematic and T-s diagram for the ideal vapor-compression refrigeration cycle.

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

10-4

FIGURE 10-4An ordinary household refrigerator.

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

10-5

FIGURE 10-5The P-h diagram of an ideal vapor-compression refrigeration cycle.

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

10-6

FIGURE 10-7Schematic and T-s diagram for the actual vapor-compression refrigeration cycle.

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

10-7

FIGURE 10-9A heat pump can be used to heat a house in winter and to cool it in summer.

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

10-8

FIGURE 10-10A two-stage cascade refrigeration system with the same refrigerant in both stages.

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

10-9

FIGURE 10-12A two-stage compression refrigeration system with a flash chamber.

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

10-10

FIGURE 10-14Schematic and T-s diagram for a refrigerator–freezer unit with one compressor.

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

10-11

FIGURE 10-15Linde-Hampson system for liquefying gases.

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

FIGURE 10-16Simple gas refrigeration cycle.

10-12

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10-13

FIGURE 10-17A reversed Carnot cycle produces more refrigeration (area under B1) with less work input (area 1A3B).

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

10-14

FIGURE 10-18An open-cycle aircraft cooling system.

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10-15

FIGURE 10-19Gas refrigeration cycle with regeneration.

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10-16

FIGURE 10-21Ammonia absorption refrigeration cycle.

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10-17

FIGURE 10-22Determining the maximum COP of an absorption refrigeration system.

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

10-18

FIGURE 10-23When one of the junctions of two dissimilar metals is heated, a current I flows through the closed circuit.

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10-19

FIGURE 10-24When a thermoelectric circuit is broken, a potential difference is generated.

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

10-20

FIGURE 10-25Schematic of a simple thermoelectric power generator.

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10-21

FIGURE 10-26A thermoelectric power generator.

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10-22

FIGURE 10-27When a current is passed through the junction of two dissimilar materials, the junction is cooled.

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10-23

FIGURE 10-28A thermoelectric refrigerator.

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