# Questions tagged [carnot-cycle]

A theoretical ideal thermodynamic cycle which provides an upper limit on the efficiency that any classical thermodynamic engine can achieve during the conversion of heat into work, or conversely, the efficiency of a refrigeration system in creating a temperature difference by the application of work to the system.

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### What stops entropy from forming if you extract 100% of heat flow and use it for work?

In a carnot engine you convert 100% of heat put inside the system during the isothermal phase into work. This is the basis of maximum efficiency and makes sure that it is reversible. If you don't ...
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### Does the Carnot efficiency apply to photoelectric conversion?

If you consider a black body as energy source and photoelectric conversion at room temperature as the energy receiver. Wouldn't it be possible to: use an ideal prism/diffraction grating to separate ...
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### How to justify that Carnot loop for ideal gas is closed on two sides by adiabatic curves?

I'm trying to figure out how to show that the orange curves connecting the two green curves are infact adiabatic: The set up is that I have an ideal gas, and I am searching for the loop when it's ...
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### How was adiabatic expansion conceived from the caloric theory perspective? [closed]

Nowadays we say that during the adiabatic expansion stage of the Carnot Cycle the internal energy due to the temperature of the gas gets transformed into work, but Carnot himself supported the caloric ...
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### How is a Carnot engine in quasi-equilibrium?

If the reversible isothermal expansion and adiabatic expansion both yield positive work (as the pv diagram indicates), it means that the gas inside the cylinder was compressed before those stages ...
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### Entropy change in each step of Carnot Cycle

How to go about calculating the entropy change in each step of a Carnot Cycle given only $T_{h}$, $T_{l}$, and the work performed per cycle?
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### How to prove the efficiency of Carnot engine is bigger than Otto engine [closed]

I know the Carnot engine has maximum efficiency among all engines from Clausius statement, but how to prove the relationship of these two engines in equation? Thanks. More specifically, the ...
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### What is the energy loss in the first process?

Suppose we have two objects with different temperatures. If we make them contact each other, they will reach the same temperature. However, if we set up a Carnot engine between them, they will also ...
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### Entropy change in a Carnot cycle

The Carnot cycle is a reversible cycle, which means that by the end of the cycle the system is in it's initial state, which is characterized by the same entropy value. Therefore we can say that for a ...
1 vote
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### The Work Done by an Irreversible Carnot Cycle

This is a question from the book, Understanding Non-Equilibrium Thermodynamics by Lebon and Jou. Show that the work performed by an engine during an irreversible cycle operating between two thermal ...
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### Comparing a gas turbine (Joule cycle) to the Carnot cycle?

My understanding of gas turbines is as follows: When you spin an impeller, you can compress air (this requires work) and when compressed air is expanded, it can be used to spin a turbine (this ...
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### Why are the pressures in the Joule-Thompson effect the same before and after?

I understand the Joule-Thompson effect and the mathematics behind it that results in the Enthalpy, $H$, remaining constant. However, one thing I conceptually fail to grasp is why the pressure on gases ...
1 vote
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### Why adiabatic expansion happens in Carnot cycle

$A \rightarrow B$: Isothermal expansion happens. Since the internal energy purely depends on the temperature ($E_{int} = knRT$, $k = \frac{3}{2},\frac{5}{2},3$), then $\Delta E_{int}=0$ in an ...