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Unformatted text preview: lly at
10°C is heated by the radiator of a steam heating system. The
radiator has a volume of 15 L and is filled with superheated vapor at 200 kPa and 200°C. At this moment both the inlet and
the exit valves to the radiator are closed. A 120-W fan is used
to distribute the air in the room. The pressure of the steam is
observed to drop to 100 kPa after 30 min as a result of heat
transfer to the room. Assuming constant specific heats for air at
room temperature, determine (a) the average temperature of air
in 30 min, (b) the entropy change of the steam, (c) the entropy
change of the air in the room, and (d ) the entropy generated
during this process, in kJ/K. Assume the air pressure in the
room remains constant at 100 kPa at all times. FIGURE P7–168
7–169 A 4-m 5-m 7-m well-sealed room is to be heated
by 1500 kg of liquid water contained in a tank that is placed in
the room. The room is losing heat to the outside air at 5°C at an
average rate of 10,000 kJ/h. The room is initially at 20°C and
100 kPa a...
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This document was uploaded on 11/28/2012.
- Spring '09