Question

It is desired to reverse the cycle and use it as a refrigerator. In this case the process would begin with PV1.36 = constant process from an initial state of 293 K and a pressure of 10 Bars. The gas is allowed to expand to a volume 3.5 times the volume of state 1. It then follows a constant volume process in which the temperature is raised to 323 K. A constant temperature is followed back to volume 1. A constant volume process then returns it to the initial state.

a) Calculate the work input for this cycle, the heat input to the cycle that could be used to cool a space at 293 K and its coefficient of performance.

b) How much total heat is removed from the system during the cycle?

c) How much total heat input is added to the system and what fraction could be used for cooling a space that is maintained at 277K?

Answer #1

Calculate the entropy production for the
piston-cylinder power producing cycle you analyzed in,
problem 1.
Problem 1: A piston cylinder device has a
volume of 0.04 m3 and initially contains air at 293 K
and 1 bar. This device is used to perform a cycle in which the gas
is heated at a constant volume until the temperature reaches 1000
K. The air is allowed to expand following an isothermal process
until the volume is 3.5 times the original volume....

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The mole number is 4.
The Cycle starts at the upper left corner A at a
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Your new engine design consists of a piston cylinder
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