Unformatted text preview: ts a state of ultimate molecular order LOAD FIGURE 7–21
Disorganized energy does not create
much useful effect, no matter
how large it is.
Wsh WEIGHT FIGURE 7–22
In the absence of friction, raising a
weight by a rotating shaft does not
create any disorder (entropy), and
thus energy is not degraded
during this process.
T FIGURE 7–23
The paddle-wheel work
done on a gas increases the level of
disorder (entropy) of the gas, and thus
energy is degraded during this process. HOT BODY Heat COLD BODY 80°C 20°C (Entropy
increases) FIGURE 7–24
During a heat transfer process, the net
entropy increases. (The increase in
the entropy of the cold body more
than offsets the decrease in the
entropy of the hot body.) cen54261_ch07.qxd 11/18/03 9:57 AM Page 290 290
FUNDAMENTALS OF THERMAL-FLUID SCIENCES Pure crystal
Entropy = 0 FIGURE 7–25
A pure substance at absolute zero
temperature is in perfect order, and its
entropy is zero (the third law of
thermodynamics). (and minimum...
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This document was uploaded on 11/28/2012.
- Spring '09