Advanced Thermodynamics for Engineers, 2nd Edition

2.7 REPRESENTATION OF HEAT ENGINES

A heat engine which operates in a cyclical manner can be represented diagrammatically as shown in

Fig. 2.1.

The direct heat engine, Fig. 2.1(a), receives heat (energy) from the high temperature reservoir at

temperature, T

1

, and rejects it to the low temperature reservoir at temperature, T

2

. The reversed heat

engine, Fig. 2.1(b), receives heat from the low temperat ure reservoir at T

2

, and pumps it to the high

temperature reservoir at T

1

.

2.7.1 EFFICIENCY OF A HEAT ENGINE

The efficiency of a direct heat engine, often referred to as the thermal efficiency, h

th

, is defined as the

ratio of useful work to the heat supplied. ...