1. CHAPTER
10
Refrigeration Cycles

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FIGURE 10-1
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.
10-1

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FIGURE 10-2
Schematic of a
Carnot refrigerator
and T-s diagram of
the reversed
Carnot cycle.
10-2

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

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FIGURE 10-4
An ordinary household
refrigerator.
10-4

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

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FIGURE 10-7
Schematic and T-s
diagram for the actual
vapor-compression
refrigeration cycle.
10-6

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FIGURE 10-9
A heat pump can be
used to heat a
house in winter and
to cool it in
summer.
10-7

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FIGURE 10-10
A two-stage
cascade
refrigeration
system with the
same refrigerant in
both stages.
10-8

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FIGURE 10-12
A two-stage compression
refrigeration system with a
flash chamber.
10-9

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

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FIGURE 10-15
Linde-Hampson
system for
liquefying gases.
10-11

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FIGURE 10-16
Simple gas
refrigeration cycle.
10-12

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FIGURE 10-17
A reversed Carnot
cycle produces more
refrigeration (area
under B1) with less
work input (area
1A3B).
10-13

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FIGURE 10-18
An open-cycle aircraft
cooling system.
10-14

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FIGURE 10-19
Gas refrigeration
cycle with
regeneration.
10-15

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FIGURE 10-21
Ammonia absorption refrigeration
cycle.
10-16

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FIGURE 10-22
Determining the maximum
COP of an absorption
refrigeration system.
10-17

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FIGURE 10-23
When one of the junctions of
two dissimilar metals is
heated, a current I flows
through the closed circuit.
10-18

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FIGURE 10-24
When a thermoelectric circuit
is broken, a potential
difference is generated.
10-19

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FIGURE 10-25
Schematic of a simple
thermoelectric power
generator.
10-20

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FIGURE 10-26
A thermoelectric power
generator.
10-21

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FIGURE 10-27
When a current is passed
through the junction of two
dissimilar materials, the
junction is cooled.
10-22

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FIGURE 10-28
A thermoelectric refrigerator.
10-23