Question
In: Mechanical Engineering
0.75 kg of refrigerant-134a at 120 kPa and 20°C initially fills a piston-cylinder device. Heat is...
0.75 kg of refrigerant-134a at 120 kPa and 20°C initially fills a piston-cylinder device. Heat is now transferred to the refrigerant from a source at 150°C, and the piston which is resting on a set of stops, starts moving when the pressure inside reaches 140 kPa. Heat transfer continues until the temperature reaches 90°C. Assuming the surrounding to be at 25°C and 100 kPa, determine (a) the work done, (b) the heat transfer, (c) the exergy destroyed, and (d) the second law efficiency of this process.
Solutions
samet mamat answered 1 month agoRelated Solutions
A piston–cylinder device contains 0.85 kg of refrigerant-134a at -10°C. The piston that is free to...
A piston–cylinder device contains 0.85 kg of refrigerant-134a at
-10°C. The piston that is free to move has a mass of 12 kg and a
diameter of 25 cm. The local atmospheric pressure is 88 kPa. Now,
heat is transferred to refrigerant-134a until the temperature is
10°C. Determine (a) the final pressure, (b) the change in the
volume of the cylinder, and (c) the change in the enthalpy of the
refrigerant-134a.
A mass of 0.3 kg of saturated refrigerant-134a is contained in a piston-cylinder device at 240...
A mass of 0.3 kg of saturated refrigerant-134a is
contained in a piston-cylinder device at 240 kPa.
Initially, 70 percent of the mass is in the liquid phase. Now heat
is transferred to the refrigerant at
constant pressure until the cylinder contains vapor only.
(a) show the process on a P-v and T-v diagrams with respect to
saturation lines. Determine;
(b) the volume occupied by the refrigerant initially,
(c) the work done, and
(d) the total heat transfer.
A mass of 0.3 kg of saturated refrigerant-134a is contained in a piston-cylinder device at 240...
A mass of 0.3 kg of saturated refrigerant-134a is
contained in a piston-cylinder device at 240 kPa.
Initially, 70 percent of the mass is in the liquid phase. Now heat
is transferred to the refrigerant at
constant pressure until the cylinder contains vapor only.
(a) show the process on a P-v and T-v diagrams with respect to
saturation lines. Determine;
(b) the volume occupied by the refrigerant initially,
(c) the work done, and
(d) the total heat transfer.
Refrigerant 134a in a cylinder-piston assembly is at 240 kPa with a quality 15% and then...
Refrigerant 134a in a cylinder-piston assembly is at 240 kPa with a quality 15% and then as a result of heat added the quality increases to 45%, what is the change in volume per one unit of mass (m3/kg)? The piston is assumed to move freely but it is sealed tight that does not allow mass exchange.
A piston?cylinder device initially contains 1.5?kg saturated liquid water at 120°C. Now heat is transferred to...
A piston?cylinder device initially contains 1.5?kg saturated
liquid water at 120°C. Now heat is transferred to the water until
the volume increases 100 times.
Determine:
a. Initial Volume of the water.
b. Final volume of water.
c. Final state of water.
d. Amount of heat added to the water
e. Draw the T?s diagram
100 kg of R-134a at 320 kPa are contained in a piston-cylinder device whose volume is...
100 kg of R-134a at 320 kPa are contained in a piston-cylinder
device whose volume is 7.530 m3. The piston is now moved
until the volume is one-half its original size. This is done such
that the pressure of the R-134a does not change. Determine the
final temperature and the change in the total internal energy of
the R-134a. (Round the final answers to two decimal places.)
100 kg of R-134a at 200 kPa are contained in a piston–cylinder device whose volume is...
100 kg of R-134a at 200 kPa are contained in a piston–cylinder
device whose volume is 12.766 m3. The piston is now
moved until the volume is one-half its original size. This is done
such that the pressure of the R-134a does not change. Determine the
final temperature and the change in the total internal energy of
R-134a. Use data from the steam tables.
The final temperature is °C.
The total change in internal energy is kJ/kg.
2 kilogram of R-134a fills a 0.14-m3 weighted piston–cylinder device at a temperature of –26.4°C. The...
2 kilogram of R-134a fills a 0.14-m3 weighted
piston–cylinder device at a temperature of –26.4°C. The container
is now heated until the temperature is 100°C. Determine the final
volume of the R-134a.
One kilogram of Refrigerant 134a vapor initially at 2 bar and 20°C fills a rigid vessel....
One kilogram of Refrigerant 134a vapor initially at 2 bar and
20°C fills a rigid vessel. The vapor is cooled until the
temperature becomes -24°C. There is no work during the
process.
Let To = 20°C, po = 0.1 MPa and ignore the
effects of motion and gravity.
2. For the refrigerant, determine the change in exergy, in
kJ.
Note: for part 1: q=-98.086kj please find part two- the change
in exergy in kj
Air of 0.5 kg mass is compressed in a piston-cylinder device from 300 K, 120 kPa...
Air of 0.5 kg mass is compressed in a piston-cylinder device
from 300 K, 120 kPa to 500K, 940 kPa. (a) Determine the entropy
change in kJ/K using (i) approximate analysis and (ii) exact
analysis. (b) Determine the direction of heat transfer (into the
device or out of the device).
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