Unformatted text preview: eratures of 20°C
and 5°C, respectively. If the rate of heat transfer through the
wall is 1035 W, determine the rate of entropy generation within
7–126 For heat transfer purposes, a standing man can be
modeled as a 30-cm-diameter, 170-cm-long vertical cylinder
with both the top and bottom surfaces insulated and with the
side surface at an average temperature of 34°C. If the rate of
heat loss from this man to the environment at 20°C is 336 W,
determine the rate of entropy transfer from the body of this person accompanying heat transfer, in W/K.
7–127 A 1000-W iron is left on the ironing board with its
base exposed to the air at 20°C. If the surface temperature is
400°C, determine the rate of entropy generation during this
process in steady operation. How much of this entropy generation occurs within the iron?
7–128E A frictionless piston-cylinder device contains saturated liquid water at 20-psia pressure. Now 600 Btu of heat
is transferred to water from a source at 900°F, and part of
the liquid vaporizes at constant pressure. D...
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