ME 336 EXAM 1,
FEBRUARY 19, 2007
C. BORGNAKKE, ME
Problem 1 (30 Points)
Superheated steam at 400 kPa, 250
o
C is flowing at 2 kg/min into a desuperheater
chamber where a flow of saturated liquid water at 400 kPa is added in
another line so the
output flow is exactly saturated water vapor at 400 kPa.
a) Find the flow rate of the saturated liquid flow
b) Find the
total
entropy generation rate in the process.
Problem 2 (30 Points)
A refrigerator receives 600 W of electrical power to the compressor driving the cycle
flow. The refrigerator has a COP of
3.0 operating with an average high temperature of
45
o
C and a low temperature of of 5
o
C.
a) Find the rate of heat transfer out of the cold space
b) Find the rate of heat transfer into the warm space
c) Find the rate of exergy destruction in the refrigeration cycle
Problem 3 (30 Points)
A harbor fire and rescue boat has a water cannon on deck. The smallest exit hole in the
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 Fall '09
 Borgnakke
 Energy, Entropy, Heat, Heat Transfer, Sgen

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