TITLE.PM5

722 ENGINEERING THERMODYNAMICS

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\M-therm\Th14-1.pm5

T=

• 5 + 273 = 268 K

3 T=

1000 + 273 = 1273 K

1

T=

25 + 273 = 298 K

4 T=

25 + 273 = 298 K

2

W = (Q – Q )

= (Q – Q )

12

43

Heat pump

Q 3

Q 4

Q 1

Q 2

Heat engine

Fig. 14.3

975

1273

=

30

298

4

1

×Q

Q

∴ Q

Q

4

1

=^975

1273

298

30

× = 7.608. (Ans.)

14.2.3. Reversed Brayton cycle

Fig. 14.4 shows a schematic diagram of an air refrigeration system working on reversed
Brayton cycle. Elements of this systems are :

1. Compressor 2.Cooler (Heat exchanger)


2. Expander 4. Refrigerator.

T

T

T

T

Air

Cooling water cooler

Cold air

Very cold

air

Expander

Refrigerator

Hot air

Warm air

Compressor

Fig. 14.4. Air refrigeration system.