This preview shows page 1. Sign up to view the full content.
Unformatted text preview: inuously
3. The performance of engineering systems is degraded by the presence of
irreversibilities, and entropy generation is a measure of the magnitudes
of the irreversibilities present during that process. The greater the extent
of irreversibilities, the greater the entropy generation. Therefore, entropy
generation can be used as a quantitative measure of irreversibilities
associated with a process. It is also used to establish criteria for the
performance of engineering devices. This point is illustrated further in
800 K Source
800 K EXAMPLE 7–2 Entropy Generation during Heat Transfer Processes A heat source at 800 K loses 2000 kJ of heat to a sink at (a) 500 K and
(b) 750 K. Determine which heat transfer process is more irreversible. 2000 kJ Sink A
500 K Sink B
750 K (a) (b) FIGURE 7–9
Schematic for Example 7–2. SOLUTION A sketch of the reservoirs is shown in Fig. 7–9. Both cases involve
heat transfer through a finite temperature difference, and there...
View Full Document
This document was uploaded on 11/28/2012.
- Spring '09